The effect of pre-heating on the morphology of the lamellae of different steel compositions sprayed by ASP

Resistance to corrosion or to wear are examples of thermally sprayed coatings purposes and these coating properties are dependent of its morphology and mainly of the lamellae properties. Lamellae are made from the impact of molten material droplets against the substrate and their solidification. To the arc spray process, the heat source is the arc electric obtained from the difference of potential between two consumable metallic wires and the transportation gas is the compressed air. The properties of the substrate surface shall be responsible for the lamellae geometric aspects, which can be irregular, splashing the material, or circular, called pankaque. The modification of the substrate temperature by pre-heating technique resulted in different geometries of the lamellae. The different materials sprayed - AISI 309L, AISI 410NiMo, AWS A5.18 E70S-6 and an experimental alloy, Fe-Mn-Cr-Si-Ni - on the substrate - glass - presented different transition temperature; below that, splashes were observed and pankaques were observed, above that.