Thermal Spray Of Ceramic Coating On Epoxy Polymer Matrix Composite

In order to overcome the poor wear resistance and thermal resistance of epoxy polymer matrix composite (EPMC), ceramic protecting coat was produced by thermal spray technology in this thesis. Optical microscope and SEM were applied to observe microstructure. EDS was applied for composition analysis.The properties, including shear bond strength, resistance to thermal shock, resistance to impact, heat insulation property and friction coefficient were tested.The results show that ceramic protecting coat can be produced by thermal spray successfully. Microstructures of the coat is compact and the coat is well-bonded to the substrate. Properties of the coat can meet the requirements. When Al₂O₃ composite ceramic was plasma sprayed directly on the substrate, the substrate was burned out. So a bond coat should be produced on the substrate firstly. Plasma sprayed A bond coat distached from substrate. Arc sprayed B, C bond coats, were not impact, and had cracks in the coats. Plasma sprayed B and arc sprayed C bond coats were impact and well-bonded to the substrate. Al₂O₃ composite ceramic coat was plasma sprayed on the bond coat, and the microstructures were impact with only a few holes. The white area was composed mostly of Al₂O₃, and the gray area was composed mostly of TiO₂.Testing of the coat's properties showed that the coat which consisting of arc sprayed D bond coat and plasma sprayed Al₂O₃ composite ceramic coat had the highest shear bond strength, 8.02 MPa. In the testing of resistance to thermal shock and resistance to impact, no crack and delamination were found in the coats, and they met the requiements. The coat had good heat insulation property. Thickness of coat had impact on the properties. As the thickness of bond coat increased, the shear bond strength, resistance to thermal shock and resistance to impact decreased. As the thickness of ceramic coat increaseed, the properties of resistance to thermal shock and resistance to impact decreased, but it's heat insulation property increased.The optimized process for thermally sprayed ceramic protecting coat on the EPMC substrate is as follows: D bond coat is arc sprayed, and Al₂O₃ composite ceramic coat is then plasma sprayed. Thickness of the bond coat is 100μm and that of the ceremic coat is 300μm.