In this study, we have examined the effects of the zincate pretreatment and heat aftertreatment on adhesion of electroless Ni–P coating onto aluminum alloy substrate.
The precipitation state of zinc was differs with the number of zincate treatment, and the double zincate treatment markedly improved the adhesion between aluminum alloy substrate and Ni–P coating. This adherent improvement can be attributed to metallurgical bond occurred by the diffusion between aluminum alloy substrate and Ni–P coating under the plating temperature (363 K×7.2 ks).
