Effect of Heat Treatment on LaTi₂Al₉O₁₉-Zr_0.92Y_0.08 O_1.96 Composite Coating Powders by Air Plasma Spraying

The nano/submicron scaled spraying powders of lanthanum titanium aluminum oxide LaTi2Al9O19 (LTA) toughened by yttria stabilized zirconia Zr0.92Y0.08O1.96 (YSZ) were prepared via spray drying and then calcined at different temperatures. The effect of heat treatment on the flowability, apparent density, and morphology of the spray-dried powders was investigated. Results show that the spray-dried powders have loose structure with the size of 40 similar to 80 mu m. The cohesion between LTA-YSZ particles becomes stronger after calcination. The spray-dried powders calcined at 1100 degrees C achieve the optimal spraying characteristics and morphology, and therefore are deposited via air plasma spraying (APS) to obtain LTA-YSZ coatings which show a good lamellar structure with defects.