Mechanisms to develop bulk-like nickel-based alloy coatings by using novel plasma spray powders with post-spray shot-peening

It has been long a great challenge to deposit fully dense bulk-like alloy coatings by thermal spraying for effective corrosion and wear protections or replacement of electroplating or additive manufacturing. In this paper, a novel approach by plasma spraying of Mo-clad NiCr powder particles hybrid with post-spray shot peening was used to create a nickel-based coating mechanically and electrochemically with the same behaviors as the casted bulk counterpart. The molten spray particles with the ultra-high temperature of over 2620¡æ for Ni-based material generated by plasma spraying will be presented. The bonding state of the resultant splat up to 90% bonding ratio with stainless steel substrate is formed by the ultrahigh molten droplets. The post-spray peening was conducted to eliminate all possible pore-like defects in the coating. It was found that mechanically bulk-like coating without permitting permeation of aqueous solution is successfully developed. Moreover, the mechanisms for developing the dense coatings is examined.