Thermal spraying of light alloys

Thermal spray coatings have been widely applied to add functions such as wear resistance, corrosion resistance, bioactivity and dielectric properties to light metals. The characteristics of the deposition process, involving splat cooling and successive stacking of splats, create coatings of unique microstructure which are different from conventional materials. In this chapter the characteristics of the thermal spray processes, and factors influencing spray particle parameters are described. The metal alloy particle oxidation, splat formation (including solid-liquid two-phase droplet impact involved in cermet coating deposition) and features of the pores in the coating are reviewed. Additionally, characterization of the coating microstructure, the dominant effect of lamellar structure on coating properties, and reactions of spray particles with the light metal substrates are examined for control of cohesion, adhesion, and properties of the coatings.