SECTIONAL TRANSACTIONS.— B. 339 



Mr. E. A. Ollard. — Non-tarnishable finishes (11. 10). 



Mr. C. F. J. Francis-Carter. — Advances in industrial electroplating 

 (ii-35).- 



Dr. H. J. T. Ellingham. — The future of electrodeposition (12.0). 



In the more restricted sense of the term, ' electroplating ' consists in the 

 production of a thin coating of a metal over the surface of a metallic object 

 by passing a direct electric current through a solution of a salt of the metal 

 to be deposited, the article to be plated being immersed in the solution and 

 forming the negative electrode or cathode. This type of process is very 

 closely related, however, to a number of others involving the electro- 

 deposition of metals — the production of relatively very thick, strongly ad- 

 herent deposits for ' building up ' worn or undersized machine parts ; the 

 formation of an oxide coating on aluminium or its alloys by using the metal 

 object as the positive electrode or anode in a suitable solution ; the produc- 

 tion of non-adherent deposits which, on detachment from the surface on 

 which they are formed, reproduce faithfully details of surface structure 

 (electrotyping) or the complete shape of an object (electroforming) — and 

 the term ' electroplating ' is sometimes used to include some or all of these 

 cognate electrodeposition processes. 



Although most of these various applications of electrodeposition were 

 devised nearly a century ago, developments during the last twenty years 

 have been so important that the scope and status of the industry have been 

 completely changed. The papers presented at this meeting furnish a 

 survey of the more important of these comparatively recent developments. 



The range of metals electroplated has been extended by the important 

 addition of chromium and recently of rhodium ; ' anodising ' of aluminium 

 and its alloys has been introduced ; and progress has been made in the 

 simultaneous deposition of two metals to give alloy coatings. The electro- 

 deposition of the ' base ' metals, zinc and cadmium, essentially for the 

 protection of iron and steel against corrosion, has become an important 

 commercial process ; and electrodeposited coatings of tin and, in special 

 circumstances, of lead, have also been applied for this purpose. The scale 

 of nickel plating has been enormously expanded, partly on its own account 

 but chiefly because of the importance of nickel as an ' undercoat ' for 

 chromium ; and the particular need for ensuring the deposition of firmly 

 adherent, regular, non-porous nickel coatings for this latter purpose has 

 greatly stimulated investigation of the factors which determine these pro- 

 perties, and has led to outstanding improvement in the quality and reliability 

 of nickel coatings. The non-tarnishable finish imparted by a thin ' flash ' 

 of electrodeposited chromium to many classes of metal ware has received 

 widespread application and has served to arouse a new interest on the part 

 of manufacturers and members of the public in electroplating in general. 

 The recent introduction of rhodium plating to furnish a non-tarnishable 

 coating on silver ware bids fair to extend this interest. In the meantime, 

 the old-established processes of plating copper, silver and gold have main- 

 tained their positions in their respective fields. 



In all these developments important parts have been played by the 

 metallurgist, the physicist, and especially the chemist. The importance of 

 close co-operation between the research laboratory and the plating shop 

 became fully recognised during the war, and is now accepted as the necessary 

 basis for progress. 



As a result of studies of the functions of various ingredients in plating 



