TiAl基合金表面低真空制备SiO_2涂层的工艺研究

A Study in Preparation of SiO_2 Coating on the Surface of Ti Al Based Alloy in Low Vacuum

为解决Ti Al基合金在750℃以上的抗高温氧化性能不足的问题,提出了采用溶胶凝胶法在其表面进行低真空制备SiO_2涂层的工艺方法。本文研究了涂膜次数对涂层表面形貌的影响,并对涂层厚度,涂层结合力,热处理后Ti Al基体抗高温氧化性等方面进行了研究,从而确定了低真空制备SiO_2涂层的可行性工艺方案。涂膜次数三层时,在Ti Al表面可以获得良好附着力和致密性高的SiO_2薄膜;在800℃高温氧化测试中,未涂膜试样氧化8h后增重2.333mg/cm2,三层涂膜试样氧化504h氧化增重仅为0.2143mg/cm2且表面没有出现剥落现象,大大提高了基体的抗高温氧化性能。

In order to solve the problem of insufficient oxidation resistance of TiA1 based alloy in high temperature, a process for preparing SiO2 coating on the surface of alloy by sol-gel method in low vacuum environment was put forward. This paper studies the impact of coating times on the coating surface morphology. Also the coating thickness, coating adhesion, the high temperature oxidation resistance of TiAl matrix after heat treatment were studied in order to find a feasible low vacuum process for the preparation of SiO2 coating. It is found that the SiO2 film with good adhesion and high density can be obtained on the surface of TiAl alloy when the coat- ing time is three. In addition, the mass gain of the film was 2. 333 mg/cm2 after the high temperature oxidation test at 800 C for 8h. Contrast to that, mass gain of the three times coated one was only 0. 6071mg/cm2 and the surface is not peeling off. This greatly improves the oxidation resistance of the alloy matrix.