Oxidation resistance of SiO_2 bonded coating formed on Ti-Al-Zr alloy

摘要

Methyl hydrogen silicone converted SiO_2 bonded composite coatings with high infrared emissivity additives of Cr_2O_3 and Al_2O_3 were prepared on Ti-6AI-2Zr-1Mo-1V titanium alloy by a dipping and then pyrolysing process. The phase composition and microstructure of the coating were characterised by X-ray diffraction and scanning electron microscopy. The results show that after exposing the samples to an oxidative atmosphere at 600°C for 100 h, the coated samples pyrolysed at 600 and 800°C exhibit a significantly lower weight gain (0.11 mg cm~(-2)) compared with that of the titanium substrate (0.54 mg crrT2). The weight gain for both coated samples oxidised at 800°C increases up to 1.4 mg cm~(-2), while the titanium substrate damages by oxide scale peeling. The coating pyrolysed at 800°C has a high infrared emissivity value of above 0.85, which is slightly higher than that of the coating pyrolysed at 600°C.