Method of electroplating aluminum and its alloys

Abstract

Abstract Aluminum or an alloy thereof is electroplated upon electrically conductive substrates by immersing the substrate as a cathode in a novel stable electrolyte, made as follows: A. reacting aluminum with a hydrogen halide such as HCl, HBr, or HI (but preferably hydrogen bromide) or reacting aluminum with a halogen such as Cl 2 , Br 2 , or I 2 (but preferably bromine), in the absence of water, but in one of the following single organic, non-Lewis base solvents or mixtures thereof: benzene, toluene, carbon disulfide, cyclohexane, dimethyl sulfide, tetrahydrofuran, diiodoethane, toluene-cyclohexane (1:1), benzene-cyclohexane (1:1), tetrahydrofuran (THF): benzene (4:1) and toluene-CS 2 (3:1) to form an intermediate aluminum halide cation in solution, the concentration of the aluminum cation and the concentration of hydrogen ion, in solution being respectively, below about 7.5 M and 0.5 M and preferably being, respectively, below about 4.2 M and 0.1 M; and B. then adding a restricted amount, preferably less than about 16 mole % relative to the initial quantity of aluminum added, of a metal halide, MX where M=Li, Na, or K and X=Cl, Br, or I; or where MX is a special halide such as beryllium bromide, magnesium bromide, or quaternary ammonium bromide to form a different, stable aluminum-cationic plating species. The novel electrolyte is then directed to a plating chamber, utilized in the plating chamber until it is aluminum ion poor, transferred to a regeneration chamber, filtered and returned to the plating chamber for further plating operations.

Inventors

• 👤 Jack Yea Wong

Bibliographic Details