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The thermal protection layer of cathode plasmaelectrolytic deposition on platinum particles was prepared on Al-Si alloy.The microstructure and the heat insulation performance, fracture toughness and bending strengthof the coating were investigated by SEM, XRD, the heat insulation test device and tensile testing machine. The distribution of platinum particles in the ceramic layer is uniform, which can effectively fill the micropores of plasma discharge. The ceramic layer is mainly composed ofα-Al2O3 and t-ZrO2, and there is the formation of high temperature stable phase Zr3Y4O12in the ceramic layer. With the increase of platinum particles, the heat insulation temperature, fracture toughness and bending strength gradually increase.After thermal shock, no obvious cracks were found on the surface of the coating, which indicated that the coating had good thermal shock resistance.

Cathode plasma electrolytic deposition ceramic coating modified by carbon nanotubes was prepared on Al-Si alloy. The microstructure and the heat insulation performance, fracture toughness and bending strength of the coating were investigated by SEM, XRD, the heat insulation test device and tensile testing machine. Carbon nanotubes(CNTs) are staggered in the ceramic layer and partially filled with plasma discharge micropores. To some extent, CNTs can promote the cathode plasma discharge and improve the film formation rate. The content of α-Al2O3 and t-ZrO2 phases increased with the increase of CNTs concentration. A certain amount of carbon nanotubes can effectively improve the insulation temperature of ceramic layer. With the increase of the content of carbon nanotubes, the fracture toughness and bending strength gradually increase.