Green preparation of silver coating on AISI 304 stainless steel surface by Ag nanocrystalline in-situ growth and the wear resistance

Ag nanocrystallines were prepared by a wet chemical technique and used as precoating materials on an AISI 304 stainless steel surface. Silver coating with a metal-like appearance was obtained via Ag nanocrystalline in-situ growth in a hydrogen atmosphere at 450 °C for 6 h. Results indicate that the Ag nanocrystalline has good dispersion and wettability due to the addition of PVP, which can affect the shape, size, and defect structure of the nanoparticles through preferential adsorption to certain crystal faces in the growth step. Bonding strength between the silver coating and substrate reached up to 40 N during the scratch test. The friction coefficient of Ag coating ranged from 0.11 to 0.13 under different degrees of loading. The in-situ growth mechanism of Ag nanocrystalline is also discussed. Compared with silver plating, the Ag nanocrystalline in-situ growth and consolidation can enhance the bonding strength of silver coating and provide a new means of preparing Ag coating without environmental pollution.