39 



Öt'versigt af Kons;!. Vetenskaps-Akademiens Förhandlingar 1894. N:o 2 



Stockholm. 



Electrolytically deposited metals. 

 By G. E. Cassel. 



[Coramnnicated 1894, Febniary 14 by P. Ki.ason.] 



In the arts of eleotrometallurgi and electroplating it is na- 

 turally of great importance that the metals be deposited in a 

 härd, firra and coherant condition. The receipes given in the 

 texthooks on this subject difFer with every metal, and it is very 

 diffieult to foresay under which conditions a metal can be obtained 

 in a desirable form. The foUowing investigations have been made 

 in order to throw some light on this coraplicated subject. 



We will then first endeavour to pro ve that in nearly all 

 known practical processes the deposited metal is a secundary 

 product; then we shall demonstrate, that it is convenient to divide 

 the metals in two classes, which differ from each other in respect 

 to the circumstances, under which they are deposited in a firm 

 condition. 



If a salt dissolved in water be decomposed electrolytically, not 

 only the positive ion of the salt appears at the cathode; it is 

 accompained by hydrogen. The presence of this gas is ac- 

 counted for, partly by a minute decomposition of the water and 

 partly by the decomposition of the acid present in the salt. Even 

 though the water and the salt be fuUy neutral the latter when 

 dissolved is partly dissociated; besides this free acid in the irae- 

 diate presence of the cathode is always generated during electro- 



