Formation and structure of plasma sprayed manganese-cobalt spinel coatings on preheated metallic interconnector plates

In the present study, plasma spraying together with a substrate pre- and simultaneous heating was found to be an appropriate technique to control the formation and densification of the coating. When plasma spraying Mn-Co spinel powder for cold substrate, high cracking effect inside the splats and in the formed coating was noticed. When applying the molten drops to the substrate heated up to 450 °C amount of cracks in single splats and coatings could be mostly eliminated. The splats stayed in the liquid state longer, which effected for spreading properties and spinel structure could be better preserved by longer crystallize time.