Modification of nickel-plating electrolyte for deposition of coatings onto aluminum and its alloys

Abstract

Composition of an electrolyte for nickel-plating of anodized surface of aluminum and its alloys was developed. It is suggested to use ammonium sulfate having rather high buffer properties in acid electrolytes as a buffer additive. It is suggested to introduce fluorine-containing substances into the electrolyte in order to obtain nickel coatings with finely crystalline structure and to raise the cathodic current efficiency. To improve the operation of the nickel anode and stabilize the cathodic process, it is recommended to introduce into the electrolyte substances of the pyridine series belonging to the class of imides. The optimal working modes of the electrolyte of this kind were determined. The electroplated nickel coatings exhibit a high adhesion to the aluminum base without an additional thermal treatment, which makes shorter the technological process of deposition of multilayer coatings.