抄録
The strength of adhesion of Cr layer electrodeposited on zinc-clad Al and Al alloys was compared, respecting to the different methods of treatment as follows: (1) Heat treatment at 380°C for 20min, in vacuum or in cracked town gas atmosphere was done after Zn intermediate electrodeposit was formed from cyanide bath on substrata which had been previously etched with some one of six kinds of acidic or alkaline solution. (2) Heat treatment was not done.
The results were: (1) On pure Al plate, adhesion was found to be pretty firm regardless of the heat treatment and the kind of etching reagent. (2) On Al Alloys of D (17S), SD (24S) and ESD (75S), heating in vacuum was effective for the stronger adhesion independently of the kind of etching reagent, though in the case of absence of heat treatment, the exfoliation was occasionally found preceding the fracture of substratum in bending test. (3) Heating in cracked town gas gave considerable improvement in regard to the adhesion, but the effect was not so remarkable as that of heating in vacuum.
