磷酸盐涂层对Ti65合金抗高温氧化性能的影响研究

Effect of Phosphate Coating on Anti-temperature Oxidation Properties of Ti65 Alloy

本文通过在Ti65钛合金表面制备Al/AlPO_(4)和Al+AlPO_(4)/SiC+AlPO_(4)两种磷酸盐涂层改善钛合金的抗高温氧化性能。通过对比研究Ti65钛合金和两种涂层样品高温氧化行为,结合SEM/EDS对涂层氧化前后组织形貌、微区成分等表征分析以及显微硬度测试,分析氧化对Ti65及涂层样品氧扩散深度的影响。650℃准等温氧化实验表明,两种磷酸盐涂层准等温氧化动力学曲线均符合抛物线规律,Ti65合金氧化增重为1.04 mg/cm^(2),Al/AlPO_(4)氧化增重为0.36 mg/cm^(2),Al+AlPO_(4)/SiC+AlPO_(4)氧化增重为0.25 mg/cm^(2),氧化增重显著降低,且Al/AlPO_(4)+SiC/AlPO_(4)复合涂层的抗高温氧化性能最好。涂层与基体之间由机械结合变成冶金结合,改善了高温钛合金的抗氧化性,防止高温钛合金基体氧化造成的硬度升高现象。磷酸盐涂层明显改善了Ti65合金的抗高温氧化性能。

In this paper,two kinds of phosphate coatings,Al/AlPO_(4) and Al+AlPO_(4)/SiC+AlPO_(4),are prepared on the surface of Ti65 titanium alloy to improve the resistance to high-temperature oxidation of titanium alloy.By comparing the high-temperature oxidation behaviour of Ti65 titanium alloy and the two coating samples,the effect of oxidation on the oxygen diffusion depth of Ti65 and the coating samples was analysed by combining SEM/EDS characterisation of the tissue morphology and micro-region compositions of the coatings before and after oxidation,as well as micro-hardness tests.The quasi-isothermal oxidation experiments at 650℃showed that the quasi-isothermal oxidation kinetic curves of the two phosphate coatings were in accordance with the parabolic law.The oxidation weight gain of Ti65 alloy is 1.04 mg/cm^(2),the oxidation weight gain of Al/AlPO_(4) is 0.36 mg/cm^(2),and the oxidation weight gain of Al+AlPO_(4)/SiC+AlPO_(4) is 0.25 mg/cm^(2),the oxidation weight gain is significantly reduced,and the composite coating of Al/AlPO_(4)+SiC/AlPO_(4) has the best resistance to high temperature oxidation.The mechanical bond between the coating and the substrate becomes metallurgical bond,which improves the oxidation resistance of high temperature titanium alloy and prevents the phenomenon of hardness increase caused by oxidation of high temperature titanium alloy substrate.The phosphate coating significantly improved the anti-temperature oxidation performance of Ti65 alloy.