The dynamics of deposit formation in thermal-spray processes

In thermal spraying, coatings are formed by particles flattening and piling up on the substrate. At impact, the sudden deceleration of the particle causes a pressure buildup at the particle-surface interface; the high pressure inside the particle forces melted material to flow laterally and ductile material to deform. The particle spreads outward from the point of impact and forms a `splat.' The principal techniques and models used to investigate splat formation are described, as well as the principal results regarding the effects of particle parameters at impact and of substrate parameters on the flattening and solidification of particles on the substrate. The particle-layering and stress-generation phenomena are also described briefly.