Abstract
Nickel was plated on steel and tin plated on top of that. The alloy films formed at the Sn-Ni interface were then analyzed by glow discharge emission spectrometry (GDS) and the effects of heat-treatment on X-ray diffraction patterns and anodic polarization curves were investigated.
The GDS results showed that interdiffusion between tin and nickel layers proceeded and a diffusion layer was formed by heat-treatment at 200°C for 4-24 hours, the thickness of which increased with increasing thickness of the tin layer and the heat-treatment time. X-ray diffraction measurements confirmed the formation of intermetallic tin-nickel compounds.
The rest potential for tin/nickel double plating films in 0.1N HCl solution shifted to a more noble potential and current values on anodic polarization curves were suppressed by heat-treatment at 200°C, while current values decreased with increasing heat-treatment time, indicating that corrosion resistance of tin/nickel double plating films was improved by heat-treatment at 200°C.
