Effect of carbon nanotubes on the microstructure and properties of CPED ceramic coating

Abstract

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.