Effect of Mild Oxidation on Ablation Properties of ZrSiO4Coating Prepared by Supersonic Atmospheric Plasma Spraying on Carbon/Carbon Composites

To eliminate the thermal expansion mismatch and improve the bonding strength between ZrSiO(4)coating prepared by supersonic atmospheric plasma spraying and C/C composites, a layer with porous structure was produced on the substrate by a preliminary air oxidation treatment. The morphology and microstructure of the ZrSiO(4)coating were characterized by SEM and XRD. The results showed the coating prepared under the condition of mild oxidation treatment exhibited good bonding strength and outstanding anti-ablation ability. After ablation for 120 s, the linear and mass ablation rates of the samples with mild oxidation were - 1.5 x 10(-4) mm/s and 0.88 x 10(-3) g/s, respectively, which were lower than those without oxidation treatment. The bonding strength of the samples with mild oxidation reached 7.9 MPa, which was 97.4% higher than those without mild oxidation. The excellent ablation resistance is attributed to the fact that oxidation treatment could make the surface rougher and enhance the bonding strength to decrease the thermal stress between the coating and substrate.