Handbook on Electroplating with Manufacture of Electrochemicals ( New Arrival ) ( ) ( ) ( ) ( )
Author Dr. H. Panda ISBN 9788178331706
Code ENI300 Format Paperback
Price: Rs 1975   1975 US$ 48   48
Pages: 484 Published 2024
Publisher Asia Pacific Business Press Inc.
Usually Ships within 5 days

 

Handbook on

Electroplating

with

Manufacture of Electrochemicals

(Electroplating of Aluminium, Cadmium, Chromium, Cobalt, Copper, Gold, Iron, Lead, Nickel, Bright Nickel, Silver, Alloy, Platinum, Palladium, Rhodium, Bright Zinc, Tin, Plastics, Barrel, Electroless Plating, Metal Treatment with Formulation, Machinery, Equipment Details and Factory Layout)

About the Book

Electroplating and Electrochemicals, industries shimmering with growth and profitability potential, are truly riveting. Electroplating, an intricate process, involves the electrodeposition of a svelte metallic stratum onto diverse substrates utilizing electric currents. This technique entails submerging the intended object, the substrate, into an electrolytic bath brimming with metal ions and, through the application of an electric current, achieves a homogeneous metallic veneer.

Conversely, Electrochemicals are birthed from electrochemical reactions. These intricate reactions are characterized by the transference of electrons among distinct compounds within an electrolytic milieu. Through the deliberate orchestration of electron flow, a plethora of chemical reactions are catalyzed, culminating in the synthesis of targeted chemicals. This methodology finds its application across a spectrum of industries, encompassing pharmaceuticals, agriculture, and energy storage sectors.

 The global electroplating market is expected to grow at a CAGR of 5.5%. The growth in the market can be attributed to the increasing demand for electroplated products from various end-use industries, such as automotive, electrical & electronics, aerospace & defense, Jewellery and machinery parts & components. In addition, the growing awareness about corrosion protection and decorative finishes is also propelling the growth of this market.

This book contains in-depth information about Electrochemical Processing, Metal Surface Treatment, Electroless Plating, Electroplating, Electroplating of Aluminium, Cadmium, Chromium, Cobalt, Copper, Gold, Iron, Lead, Nickel, Bright Nickel, Silver, Alloy, Platinum, Palladium, Rhodium, Bright Zinc, Tin, Plastics, Barrel, Zinc Electroplating Brightener, Metal Treatments, Electrodeposition of Precious Metals, Electropolishing of Stainless Steel, Case Hardening, Electroless Coating of (Gold, Silver), Buffing and Industrial Metal Polishing Compounds, Aluminium, Gold and Its Compounds, Complex Salts of (Copper, Silver and Gold), Hydrides of Silicon, Chemical and Electrochemical Conversion Treatments, Electrostatic Sealing.

This book is an invaluable resource that comprehensively addresses all the essential topics in Electroplating and Electrochemicals. It is poised to become a standard reference for professionals and entrepreneurs interested in this field, offering a comprehensive understanding of Electroplating. Additionally, it will prove highly beneficial to consultants, new entrepreneurs, technocrats, research scholars, libraries, and existing businesses. The book offers a detailed roadmap that guides readers from the initial concept to the machinery acquisition phase.

 

 

                                      Contents                                                

   1.   Electrochemical Processing                                                         1-24

         INTRODUCTION                                                                                        

         THE ELECTROCHEMICAL CELL                                                              

         INORGANIC                                                                                                

         Hardware for Electrochemical Processing                                         

         Production Conditions                                                                   

         Electrolysis of Chloride Solutions                                                       

         Organic                                                                                                        

         Hardware for Electro-Organic Processing                        

         Cells                                                                                                             

         Electrodes                                                                                                  

         Electrolytes                                                                                               

         Diaphragms                                                                                                

         Cell Designs                                                                                               

         Scale-Up-Consideration                                                                          

  2.   Metal Surface Treatments                                                         25-40

         CLEANING, PICKLING, AND RELATED PROCESSES                         

         Cleaning                                                                                                      

         Solvent Cleaning                                                                                       

         Wiping                                                                                                        

         Emulsifiable Solvents                                                                             

         Emulsion Cleaning                                                                                   

         Diphasic Chlorinated Solvents                                                              

         Vapour Degreasing                                                                                   

         Ultrasonic                                                                                                  

         Alkaline                                                                                                       

         Immersion                                                                                                 

         Spray                                                                                                           

         Ultrasonic Alkaline                                                                                  

         Steam                                                                                                          

         Electrocleaning                                                                                         

         Pickling                                                                                                       

         (a) Chemical for Pickling                                                                         

         Sulphuric Acid:                                                                                         

         Hydrochloric Acid:                                                                                   

         Nitric Acid:                                                                                                

         Phosphoric Acid:                                                                                      

         Chromic Acid:                                                                                            

         Hydrofluoric Acid:                                                                                   

         Other Pickling Acid:                                                                                 

         The practice of Electrolytic Pickling:                                                  

         Chemical and Electrolytic Pickling Compared                 

         Anodic Cathodic Pickling Compared:                                                  

         Tin and Lead Additions:                                                                          

         Regeneration of Pickling Solutions                                                     

         Pickling Before Electroplating                                                              

  3.   Electrolytic machinery methods                                              41-54

         PRINCIPLES OF THE ECM PROCESS                                                     

         The Solution Gap                                                                                      

         Electrolytes                                                                                               

         Temperature Effects                                                                                

         Corrosion products                                                                                  

         Pressure Effects                                                                                        

         TYPES OF ECM OPERATIONS                                                                 

         MODERN DEVELOPMENT OF THE ECM PROCESS                             

         Electrolyte Development                                                                        

         Fundamental Investigation                                                                   

         Innovations in ECM Operation                                                              

         Static Fixture Finishing and Sizing                                                     

         Embossing                                                                                                 

         Broaching                                                                                                   

         Uses                                                                                                             

  4.   Electroless Plating                                                                       55-86

         THEORY                                                                                                       

         Equipment                                                                                               

         Plating Tanks                                                                                             

         Rack Design and Loading Factors                                                         

         Safety and Waste Disposal                                                                     

         Plating on Metals                                                                                     

         Preparation of the Substrate                                                                 

         Plating on Nonconductors                                                                     

         Plating of Plastics                                                                                    

         Process Details                                                                                          

         Printed Circuits                                                                                         

         Printed-Circuit Etchants                                                                         

         Emerging Printed-Circuit Technologies                                             

         Plating on Glass                                                                                        

         Architectural Glass                                                                                  

         Ceramic Plating                                                                                         

         Composite Plating                                                                                    

         ELECTROLESS COMPOSITE COATINGS                                                

         USES AND APPLICATIONS:                                                                    

         Nonelectrolytic Plating Processes                                                       

         Immersion Plating                                                                                   

         Autocatalytic Plating                                                                              

         Postplating Treatments                                                                

         Specification and Tests                                                                  

         Thickness                                                                                                   

         Corrosion Resistance                                                                               

         Adhesion                                                                                                     

         Applications                                                                                          

         Decorative Plating                                                                                    

         Plating for Protection                                                                             

         Special Surface Effects                                                                           

         Engineering Applications                                                                       

         Electroforming                                                                                         

  5.   Electroplating                                                                             87-107

         THE SUBSTRATE IN ELECTROPLATING                                              

         Preparation of the Substrate                                                     

         Cleaning                                                                                                      

         Rinsing                                                                                                        

         Acid Dipping                                                                                              

         Drag-Out and Drag-In                                                                              

         Special Preparation Cycles                                                                     

         Aluminium and Magnesium                                                                   

         Zinc-Base Die Castings                                                                            

         Refractory Metals                                                                                    

         Other Metals                                                                                              

         Nonconductors                                                                                         

         The Electroplating Process                                                                    

         Continuous Plating                                                                                  

         Materials of Construction                                                                      

         Economics                                                                                                  

         Safety                                                                                                          

         Waste Disposal and Metal Recovery                                                    

         Plating Solutions                                                                              

         Current Density Range                                                                            

         Throwing Power                                                                                       

         Acidity                                                                                                        

         Anodes                                                                                                        

         Temperature                                                                                              

         Purity                                                                                                          

         Bright Plating                                                                                            

         Maintenance of Plating Baths                                                                

         Individual Plating Baths                                                              

  6.   Electroplating plant                                                                108-114

         Plant Requirements                                                                         

         Buildings                                                                                                    

         Supporting the Work to be Plated                                                        

         Tanks                                                                                                           

         Filtration                                                                                                    

         Air Agitation                                                                                              

         Water Supply                                                                                             

         Heaters                                                                                                        

         Maintenance of the Solution                                                                 

         Effluent                                                                                                       

         Electroplating Plant                                                                      

  7.   Electroplating of aluminium                                                115-120

         Surface Roughening                                                                                 

         Anodising                                                                                                   

         Zincating                                                                                                    

         Note :                                                                                                           

         Alstan Process                                                                                           

         Plating Process                                                                                         

         Silver-Tin Plating                                                                                     

         Alstan Process                                                                                           

  8.   Electroplating of cadmium                                                   121-128

         The Solution                                                                                              

         Additions to the Solution                                                                       

         Anodes                                                                                                        

         Thickness of Deposit                                                                               

         Operating Conditions                                                                              

         Anti-Corrosion Properties of Cadmium                                              

         Nickel on Cadmium                                                                                  

         Heat Treatment of Cadmium Deposits                                                

         Cadmium and Food Stuffs                                                                      

         Bright Cadmium Plating                                                                         

         Applications of the Cadmium-Plating                                                 

  9.   Electroplating of chromium                                                 129-136

         The Electrolyte                                                                                          

         Chromium Plating Process                                                                     

         Regeneration of Chrome Plating Solutions                                        

         Coloured Chromium Plating                                                                  

         Chromium Plating on Aluminium                                                        

10.   Electroplating of cobalt                                                          137-141

         Principles                                                                                                   

         Functions of Constituents of Bath                                                       

         Operating Conditions                                                                              

         Maintenance and Controls                                                                      

         Preparation of Basis Metals and Finishing of Deposits              

         Tests of Deposits                                                                                      

11.   Electroplating of copper                                                        142-144

         Copper Sulphate Plating Bath                                                     

         Operating Condition                                                                                

         Bright Plating                                                                                     

         Cyanide Bath                                                                                          

         Composition                                                                                              

         Sodium Formulation                                                                        

         Operating Condition                                                                                

         Potassium Formulations                                                               

12.   Electroplating of gold                                                             145-160

         Stripping Gold                                                                                      

         Gold Baths                                                                                              

         Bath for Gold Gilding                                                                               

         Current-Density, 0.15 Ampere                                                              

         Gold Baths For Hot Gilding                                                           

         Tanks for Gold Baths                                                                               

         Execution of Gold-Plating                                                                      

         For Gold-Plating in The Cold Bath the Process

         is as Follows :                                                                                      

         Re-Gilding                                                                                                  

         Application of Gold-Deposition                                                            

         Gold Thread                                                                                           

         Process                                                                                                        

         Gold Plating of Stainless Steel Ornament                         

         Methods of Plating Stainless Steel                                                      

         Plating Procedures                                                                                   

13.   Electroplating of iron                                                              161-165

         Principles                                                                                                   

         The Iron Chloride Bath                                                                   

         The Iron Sulphate Bath                                                                   

         The Fluoborate Bath                                                                         

14.   Electroplating of lead                                                             166-169

         Analysis of Lead Solution                                                             

         Free Acid                                                                                                     

         Applications of Lead Plating                                                       

15.   Electroplating of nickel                                                          170-176

         Types of Ni Solutions                                                                       

         Engineering Application                                                                         

         Ni And Ur Plating Butterworths                                              

         Electroplating Baths used                                                                      

         Watts Nickel Bath                                                                                    

         Hard Watts Bath                                                                                       

         Nickel Sulphate Bath                                                                               

         Nickel Sulphonate Bath                                                                           

         Nickel Fluoborate Bath                                                                           

         Barrel Nickel Plating                                                                                

         Black Nickel :                                                                                             

         Black Ni Plating Processes                                                                     

         Types of Nickel Plating Solutions Used                                

16.   Electroplating of bright nickel                                            177-178

         Carriers                                                                                                   

         Nickel Electroplating Brighteners                                        

17.   Electroplating of silver                                                          179-188

         Silver (Atomic weight=107.88) and Its Properties :                       

         Silver Bath for a Heavy Deposit of Silver (Silvering by Weight):

         Preparation of Bath I, With Silver Chloride                      

         Preparation of Bath II with Silver Cyanide                        

         Silver Bath for Ordinary Electroplating                            

         Tanks for Silver Baths                                                                             

         Execution of Silver-Plating                                                        

         Silver Plating by Weight                                                                        

         Bright Silver Plating                                                                      

         Source of Brightening in Carbon Disulphide Electrolytes              

18.   Electroplating of alloy                                                            189-193

         Electrodeposition of Zinc-Iron Alloy                                                  

         Lead-Tin Plating                                                                                       

         Speculum Plating                                                                                     

         Gold Alloy Plating                                                                                    

         Bright Alloy Plating                                                                                 

         Ni-Alloy Plating                                                                                        

         Bronze Plating                                                                                           

         Copper Solution                                                                                        

19.   Electroplating of platinum                                                    194-197

         (1) Keital and Zschiegner Process                                             

         (2) Powell and Scott Process                                                       

         Conditions of Operation                                                                

         Maintenance of Electrolyte                                                        

20.   Electroplating of palladium                                                 198-200

         (A) Soluble Anode Process                                                             

         Condition of Operation                                                                           

         Properties of the Deposit                                                                       

         (B) Diaphragm Process                                                                     

         Condition of Operation                                                                           

21.   Electroplating of rhodium                                                   201-208

         Predeposition                                                                                       

         Palladium Plating                                                                                     

         Solution Agitation                                                                           

         Raw material used for Palladium Plating                                           

         Equipment                                                                                                  

         Rhodium Plating                                                                                 

         Tank                                                                                                             

         Tank Installation                                                                                      

         Solution Heating                                                                                      

         Rectifier                                                                                                      

         Rectifier Control                                                                                       

         Current Control                                                                                         

         Temperature Control                                                                               

         Making of Rhodium Plating Bath                                                         

         Rhodium                                                                                                   

         Method A—Colorimetric                                                                         

         Discussion of the Method                                                                      

         Method B                                                                                                    

         Discussion of the Method                                                                      

         Method C—Hydrazine Reduction                                                          

         Discussion of the Method                                                                      

         Sulphate                                                                                                      

         Applications of the Precious Metals                                      

22.   Electroplating of bright zinc                                               209-212

         Bright Zinc-plating Processes                                                    

         Chemical Control                                                                                      

         Electrolytic Impurities                                                                           

         Anodes                                                                                                        

         Advantages of Bright Zinc Plating                                          

23.   Electroplating of tin                                                               213-215

         INTRODUCTION                                                                                        

24.   Electroplating of plastics                                                       216-221

         The Plating of Plastics and Non-metallic Materials   

         1.   Polishing with Plumbago                                                                  

         2.  Metallising with Copper Bronze Powder                                       

         3. Metallisation by Molten Metal Spraying                                      

         4. Metal Surfacing of Ceramics by “Firing”                                       

         5. Vacuum Evaporation and Electrical Sputtering                           

         6. Silver Mirror Process as Applied to Plastics                                 

         Removal of Glaze                                                                                      

         Cleaning                                                                                                      

         “Sensitising”—The next step is to                                                       

         Silvering                                                                                                     

         Coppering                                                                                                   

         Silver Recovery                                                                                         

25.   Electroplating of barrel                                                         222-232

         Barrel Nickel-Plating                                                                     

         Barrel Coppering                                                                                       

         Brass Barrelling                                                                                         

         Barrel Cadmium                                                                                        

         Barrel Zinc                                                                                                  

         Barrel Silver                                                                                               

         Electro-Galvanising Tray                                                                        

         Barrel Polishing                                                                                        

         Barrel Tin                                                                                                    

         Applications                                                                                          

26.   Zinc electroplating brightener                                            233-236

         Uses and Applications                                                                     

         Properties of the Brightener                                                      

         Formulations                                                                                       

         Operating Conditions                                                                      

         Temperature                                                                                              

         Current Efficiencies                                                                                 

         Throwing Power                                                                                       

         Conductivity and polarization                                                              

         Manufacturing Process                                                                 

         Formulation                                                                                         

27.   Colouring of metals                                                                 237-245

         1.  Direct Coloration of Iron and Steel by Cupric Selenite :              

         2.  Coloration of Copper and Brass with Cupric Selenite :                

         Metal Browning by Oxidation                                                     

         Copper Colouring                                                                               

         (a) Blacking Copper                                                                                  

         (b) Red Colour to Copper                                                                        

         Coloring of Brass                                                                               

         Brass Colouring                                                                                         

         Coloring Brass                                                                                           

         Bronzing                                                                                                  

         Art Bronzes :                                                                                              

         Antique Bronzes                                                                                        

         Vert Antique                                                                                              

         Brass Bronzing                                                                                          

         Copper Bronzing                                                                                       

         Bronzing of Cast Iron                                                                      

         Liquid for Bronze Powder                                                                       

         Bronzing of Cannon                                                                                  

         Green Bronzing                                                                                          

         Bronzing of Steel                                                                               

         Tin Bronzing                                                                                          

         Zinc Bronzing                                                                                       

28.   Metal treatments                                                                    246-270

         Mechanical Treatments                                                                 

         Workability Testing                                                                                

         Plastic Deformation                                                                                 

         Hot Working                                                                                              

         Cold working                                                                                             

         Primary Forming Processes                                                                   

         Secondary Forming Processes                                                              

         Thermal Treatments                                                                        

         Annealing                                                                                                   

         Heat Treatment of Steel                                                                          

         Homogenization                                                                                       

         Thermo mechanical Processing                                                            

         Recent Development and Outlook                                             

         Powder Metallurgy of Superalloys                                                      

29.   Electrodeposition of precious metals                                271-272

         Physical Properties                                                                                  

30.   Electropolishing of stainless steel                                     273-286

         Application                                                                                                

         Baths                                                                                                         

         Experimental                                                                                        

         Bath Composition                                                                                     

         Hull Cell Studies                                                                                       

         Rates of Dissolution                                                                                

         Effect of Polishing Time                                                                         

         Life of the Bath                                                                                         

         Practice of Electropolishing                                                      

         (i) Sequence of Operations                                                                     

         (iii)                                                                                 Electropolishing               

         (iv)                                                  Treatments After Electropolishing               

         (v) Equipment for Electropolishing                                                      

         (vi)                                                     Technical and Economic Aspects               

         Applications of Electropolishing                                            

         1.   Decorative Finishing                                                                          

         2.   Polishing of Parts Exposed to Friction                                           

         3.   Electropolishing Cutting Tools                                                        

         Drills and Taps                                                                                          

         Wood Working Tools                                                                              

         Solutions Employed                                                                                

         4.   Polishing of Measuring Instruments                                             

31.   Case hardening                                                                        287-301

         Processes                                                                                                

         Carburizing                                                                                                

         Gas                                                                                                               

         Liquid                                                                                                          

         Pack                                                                                                             

         Carbonitriding                                                                                           

         Gas                                                                                                               

         Cyaniding                                                                                                   

         Nitriding                                                                                                     

         Gas                                                                                                               

         Liquid                                                                                                          

         Microcasing                                                                                               

         Ionitriding                                                                                                 

         Siliconizing                                                                                                

         Boronizing                                                                                                  

         Tufftriding                                                                                                 

         Triniding                                                                                                     

         Applied Energy                                                                                          

         Induction Hardening                                                                               

         Flame Hardening                                                                                      

         Other                                                                                                            

         Hardening                                                                                                   

32.   Electroless coating of gold, silver                                     302-321

         Methods for Mirroring                                                                            

         Electroless Process                                                                          

         Equipment                                                                                                  

         Silver Colouring for Mirror (Silver Coating)                  

         Formulation-1                                                                                           

         Preparation                                                                                                

         Formulation-2                                                                                           

         Preparation                                                                                                

         Process of Manufacture                                                                

         1. Selection of glass sheet                                                                       

         2. Cleaning of glass sheet                                                                       

         3. Sensitizing                                                                                            

         4. Silvering on glass                                                                                 

         Plating Procedure                                                                             

         Silvering of Glass                                                                             

         Chemical Silvering                                                                                   

         To prepare the bath                                                                                  

         Cleaning                                                                                                      

         Gold Colouring for Mirror (Gold Coating)                         

         Formulations for Electroless Gold Bath                            

         Manufacturing Process for Gold Plating                           

         Blue Silvering on Glass with Copper Coating                    

         Formulation of Blue Silvering on Mirror                          

         Manufacturing Process                                                                 

         Copper Coating                                                                                     

         Plating Bath Formulation                                                            

         Bath Constituents                                                                                     

         The Operation of Electroless Copper Baths                        

         Red Mirror by Electroless Dipping Method                                       

         Electroless Copper Plating of Plain Glass to Manufacture Red Mirror        

         Manufacture Process of Red Mirror                                      

         Test for Electroless Plated Red Mirror Adhesion          

         Baking Test                                                                                                

         Burnishing Test                                                                                         

         Test for Continuity                                                                           

         Ferroxy Test                                                                                              

         Marking                                                                                                   

33.   Buffing and industrial metal polishing compounds   322-329

         Abrasives for Buffing                                                                              

         1. Tripoli                                                                                                     

         2. Vienna Lime                                                                                           

         3. Aluminium Oxide (Sophire)                                                               

         4. Rouge                                                                                                      

         5. Amorphous Crystalline Silica                                                            

         6. Emery                                                                                                      

         Buffing & Polishing Compositions                                                       

         Manufacturing Method of Buffing Compounds               

         Carborundum for Polishing                                                        

34.   Tin and its compounds                                                           330-337

         Discovery                                                                                                   

         Mineralogy                                                                                                 

         Extraction                                                                                                  

         Metallurgy                                                                                                 

         Refining of Crude Tin                                                                              

         Properties of Tin                                                                                       

         General Account of Tin and its Compounds                                       

35.   Lead and its compounds                                                        338-347

         Discovery                                                                                                   

         Mineralogy                                                                                            

         Smelting in a Blast Furnace                                                                   

         Purification of Lead                                                                                 

         Properties of Lead                                                                                    

         Chemical                                                                                                     

         Technology                                                                                                

         White Lead, Pb (OH)2 . 2PbCO3                                                            

         Super-sublimed White Lead                                                                  

36.   Manufacture of phosphorus                                                348-352

         Modern Electric Process                                                                         

         Manufacture in India                                                                               

         Purification                                                                                                

         Smithel’s Cold Flame                                                                               

         Luminescence                                                                                            

         Manufacture of Red Phosophorous                                                      

37.   Hydrides of phosphorus                                                        353-360

         Phosphorous Trihydride, or Phosphine PH3                                      

         Properties                                                                                                   

         Phosphonium Iodide, PH4I                                                                    

         Hydrogen Hemiphosphide, P2H4                                                         

         Hydrogen Diphosphide, P12H6                                                             

         Other Hydrides of Phosphorous                                                           

38.   Chemistry of sodium                                                               361-367

         Mineralogy                                                                                                 

         Metallurgy                                                                                                 

         Down’s Process—Electrolysis of Sodium Chloride                          

         Castner’s Process ( From fused sodium hydroxide)                        

         Properties                                                                                                   

         Technology                                                                                                

         Caustic Soda Industry in India                                                              

39.   Copper and its compounds                                                    368-376

         Mineralogy                                                                                                 

         Extraction                                                                                                  

         Extraction from sulphide ores                                                              

         Concentration                                                                                            

         Metallurgy furnace for Smelting Copper                                            

         Extraction from Non-Sulphide Ores                                                    

         Properties                                                                                                   

         Chemical                                                                                                     

         Technology                                                                                                

         Cupric Sulphate, CuSO4 5H2O                                                               

         Properties                                                                                                   

40.   Silver and its compounds                                                      377-385

         Mineralogy                                                                                                 

         Metallurgy                                                                                                 

         Purification                                                                                                

         Properties                                                                                                   

         Chemical                                                                                                     

         Technology                                                                                                

         Silver Nitrate                                                                                             

         Industrial Applications                                                                           

         Photography                                                                                              

41.   Gold and its compounds                                                        386-393

         Mineralogy                                                                                                 

         Metallurgy                                                                                                 

         Cyanide Process                                                                                        

         Purification                                                                                                

         Properties                                                                                                   

         Chemical                                                                                                     

         Technology                                                                                                

         Electroplating                                                                                           

42.   Complex salts of copper, silver and gold                          394-398

         Complex compounds of Silver                                                              

         Complex Salts of Gold                                                                             

43.   Aluminium and its compounds                                            399-410

         Mineralogy                                                                                                 

         Extraction                                                                                                  

         Metallurgy                                                                                                 

         Properties                                                                                                   

         Chemical                                                                                                     

         Technology                                                                                                

         Aluminium Chloride, AlCl3                                                                    

         Properties                                                                                                   

         Potash Alum, K2SO4. AI2(SO4)3. 24H2O                                           

         Amalgam Metallurgy                                                                               

44.   Hydrides of silicon                                                                    411-419

         Silicon Tetrahydride, Silicane, or Monosilane, SiH4                       

         Preparation                                                                                                

         Properties                                                                                                   

         Silicoethane, Disilicane,Disilane, Si2H6                                            

         Properties                                                                                                   

         Silicopropane, Trisilicane or Trisilane, Si3H3                                  

         Preparation                                                                                                

         Properties                                                                                                   

         Silicobutane, Tetrasilicane or Tetrasilane, Si4H10                          

         Silicopentane, Si5H12 and Silicohexane, Si6H14                             

         Silico-acetylene, (Si2H2)n                                                                     

         Structural Considerations                                                                      

         Short Note on Silicones                                                                          

45.   Chemical and Electrochemical conversion treatments 420-431

         PHOSPHATING                                                                                          

         Coating Formation                                                                                   

         Process Parameters                                                                                  

         Uses                                                                                                             

         ANODIZING                                                                                                

         METAL COLOURING                                                                                 

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Electrochemical Processing

INTRODUCTION

Electrochemical processes involve the interconversion of electrical and chemical energy by means of a reaction at an electrode. Electrical charge may be fed to an electrolysis cell to induce chemical reactions (synthesis, metal winning or refining, etc), or chemical reactions may be run in a cell to generate electricity (batteries, accumulators, fuel cells) (see Batteries). Since the electrode reaction occurs at a surface, electrochemical techniques may also be used for surface treatment (electroplating (qv), electropolishing, anodizing) (see Metal surface treatments) or machining (see Electrolytic machining methods).

        Electrosynthesis was first carried out by Davy in 1807 for the production of sodium and potassium, and in 1833 by Faraday who performed the first known example of the Kolbe reaction. Today this reaction remains one of the most useful in organic electrosynthesis. Generally speaking, all chemical reactions may be performed electrochemically and there are often great advantages to be obtained in doing so: electrochemical reactions allow control of selectivity and reaction rate through the electrode potential; are inherently pollution-free; have high thermodynamic efficiency; make possible reactions at ambient temperature; can often reduce the number of reaction steps; can often use cheaper starting materials; by means of electrolytic regeneration can use catalytic quantities of chemical oxidizing or reducing agents; and can often perform a synthesis electro generatively.

                However, disadvantages are: electrochemical engineering and technology are far less developed than chemical engineering; many reaction variables may be involved with complex interdependences; long term stability of process components is often poor; and workup of product is often costly.

THE ELECTROCHEMICAL CELL

        An electrochemical cell consists of at least two electrodes (anode and cathode) that dip into an electrolyte contained in a cell or reactor housing. The cell may be constructed so that the electrolytes at the anode and cathode are separated (anolyte and catholyte). One of the first cells studied was the Daniell cell and it is used as the basis of many introductions to the thermodynamics of electrochemical processes (2). It consists of a zinc anode and copper cathode dipped into solutions of their sulfates. A porous separator prevents mixing of the two solutions. Symbolically the cell is written :

Cu|Cu2+|Zn2 =|Zn

INORGANIC

        Electrochemical process involve the transfer of electrons between an electrode and a substrate in solution. The energy required is in the range 0-3.5 h eV, and depends on the electrode material and the substrate. This is a moderate energy input in comparison to photochemical or radiation activation methods. Nevertheless, it is sufficient to produce the strongest oxidizing and reducing agents known, i.e. F2  and solvated electrons, respectively. It would indeed be difficult to develop manufacturing processes for chlorine, sodium, and fluorine that improve on the electrochemical ones (products; Chemicals from brine; Fluorine).

        The importance of the electrochemical processing of inorganic chemicals for the production of either elements or compounds is easily appreciated from the fact that in the U.S. they consume 6% of all the electricity generated or about 16% of the electricity used by industry. Table 1 lists the most important processes that are now practiced, however, other industrial operations that involve an electrode reaction, e.g., metal refining, (see Aluminium; Extractive metallurgy), energy sources (batteries, fuel cells, electroplating (qv), electropolishing, anodizing, electrochemical machining are not discussed in this article.

Hardware for Electrochemical Processing

        The distinguishing feature of an electrochemical process is t