Effect of heat treatment to Ni-20wt.Al coating diffusion

摘要

Ni-20wt.%Al coating was fabricated on the 6061-T6 aluminum alloy substrate in twin wire arc spraying technology. Heat treatment temperature was 400°C, 480°C and 550°C, and each heat treatment time was 4 h, 24 h and 48 h. Reaction mechanism and diffusion behavior of elements of coating/substrate interface were discussed. The XRD results showed that NiAl and Ni_3Al phases were diminished and the nickel solid solution was gradually improved in volume. And some oxide phases existed, such as two types of alumina and nickel oxides. The SEM and EDS analysis showed, there was no obvious diffusion. At the low temperature condition, the diffusion phenomenon was existed in the interface.