金属载体表面玻璃涂层的表征及结合强度

Characterization and bonding strength of glass coating on metallic substrate

为解决由于热膨胀系数不同而引起的涂层脱落问题,采用溶胶-凝胶法制备玻璃涂层,涂覆于Ni-Cr-Fe金属载体表面。通过XRD和SEM表征载体和涂层的微观结构,超声振动、热冲击和拉伸实验,评价Ni-Cr-Fe金属载体与玻璃涂层的结合能力。实验结果表明,金属载体表面预处理可以提高载体的几何表面积,载体在900℃高温氧化5 h,出现成簇浮凸状形貌。制备的玻璃涂层均匀、致密,厚度约7.8μm,呈非晶态结构。在超声振动实验中脱落率小于20%,热冲击实验中脱落率小于10%,玻璃涂层具有较高的结合强度。

In order to solve peeling of coating due to the difference in thermal expansion coefficients between coating and substrate, a glass coating with and without oxide additive on Ni-Cr-Fe metallic substrate was prepared by sol-gel method. The microstructure of the substrate and glass coating were investigated by XRD and SEM, and the bonding strength between the coating and Ni-Cr-Fe metallic substrate was examined by means of ultrasonic vibration, thermal shock and tensile test. The results indicate that the metallic substrate surface pretreatment can increase the geometric surface area and surface relief structures form after the cleaned substrate is calieined at 900℃ for 5 h. The glass coating with a thickness of 7.8 μm prepared by sol-gel method on the pretreated metallic subsrate is dense and homogeneous, and the structure is amorphous. The weight loss of glass coating is less than 20% in the ultrasonic test and less than 10% in the thermal shock test, and the coating exhibits a good bonding strength to substrate.