烧结温度对热障涂层组织及性能的影响

Effect of sintering temperature on microstructure and properties of thermal barrier coating

因为热障涂层高温使用过程中不可避免会发生烧结现象,易引起涂层的失效。本文采用了等离子喷涂设备制备YSZ涂层,并对其分别在1000、1100、1200和1300℃下进行保温不同时间的高温烧结试验,研究其高温烧结过程中的微观结构及力学性能的变化规律。结果表明:高温烧结后涂层断面的抛光组织未见明显变化。涂层孔隙率呈整体下降趋势,在长时间烧结后,基本稳定在12%~14%范围中;涂层弹性模量和显微硬度在初期(0~50 h)的增长速率远高于后续烧结过程;且烧结温度越高,涂层硬度和弹性模量增长幅度越大,且快速增长阶段越短。

Because the sintering phenomenon of thermal barrier coating is hardly avoided in the service process at high temperature,the failure of the coating is easily happened. High temperature sintering test was carried out on the YSZ coating,which was prepared by plasma spraying,to study the evolution law of microstructure and mechanical properties at 1000,1100,1200 and 1300 ℃ for different time,respectively. The results show that the cross-sectional microstructures of YSZ coating after 500 h sintering treatment are similar to the assprayed one. The porosity is in the overall downward trend,and the early stage（ 0-50 h） decline rate is much higher than that of the subsequent heat preservation stage. As a whole,the porosity of coating deceases gradually,which ranging from 12% to 14% after sintering for a long time. The growth rate of elastic modulus and micro-hardness of coating in the early stages（ 0-50 h） are much higher than those of subsequent sintering process. And with the sintering temperature increasing,the extent of elastic modulus and micro-hardness of coating increasing is larger,and the rapidly increasing stage gets shorter.