The effects of phosphoric acid chemical treatment and composite SiO2 coating on oxidation resistance of Ti-6Al-4V alloy were investigated.Results show that,the average oxidation rate of the Ti-6Al-4V alloy treated by phosphoric acid decreases nearly by 75％ in comparison with the blank samples at 600℃ after 24h oxidation in air.The oxidation rate of composite SiO2 coating sample reduces one order of magnitude in comparison with the blank sample oxidation for 100h at the same condition.The composite SiO2 coating has better anti-oxidation ability than phosphoric acid treatment.The compactness of the oxide scale of the composite SiO2 coating and the phosphoric acid treatment samples increases,and a good adhesion with the substrate is shown,the volume fractions of TiO2 in oxidation films reduce both phosphoric acid chemical treatment and composite SiO2 coating samples.The in-diffusion of O and out-diffusion of Ti are restrained because of the formation of TiP2O7 phase and deposit SiO2 coating.%研究磷酸表面处理和复合SiO2涂层对Ti-6Al-4V合金600℃下空气中抗氧化性能的影响.结果表明:600℃氧化24h后,磷酸表面处理使Ti-6Al-4V合金平均氧化速率下降了近75％,复合非晶SiO2涂层样品600℃等温氧化100h后,平均氧化速率比空白样品降低一个数量级,抗氧化性能与单独的磷酸处理比较进一步提高.磷酸表面处理和复合SiO2涂层样品的氧化膜致密性增强且与基体的黏附性良好,二者氧化膜中TiO2的体积分数均低于空白样品.磷酸表面处理形成的TiP2O7层与SiO2涂层共同抑制了O的内扩散和Ti的外扩散.
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