C/SiC复合材料抗热震涂层制备及失效机制研究

Preparation of Thermal Shock Resistance Coatings on C/SiC Composites and Failure Mechanisms

在C/SiC材料上制备环境障碍涂层是对C/SiC高温防护的有效解决办法。利用化学共沉积法制备BaO-SrO-Al_2O_3-SiO_2(BSAS),ZrO_2-Y_2O_3(YSZ),Sc_2O_3-ZrO_2-Y_2O_3(ScYSZ)粉末材料,然后采取相同的等离子喷涂工艺参数在C/SiC复合材料表面制备3种抗热震(水淬)涂层。本文主要涉及到抗水淬涂层结构设计、0.2mm厚涂层的抗水淬性能、4种不同厚度涂层的抗水淬能力、涂层失效机制等研究内容。研究结果表明:C/SiC复合材料上0.2mm厚的抗水淬涂层,在1600℃下其抗水淬能力强弱为ScYSZ(24次)>YSZ(22次)>BSAS(21次)。0.2,0.3,0.5及0.6mm4种不同厚度对涂层的抗水淬能力影响规律表明:厚度为0.2mm时涂层具有最优的抗水淬性能。并探讨了涂层的失效机制:BSAS,YSZ,ScYSZ3种涂层,其YSZ相稳定性最差,BSAS作为单一的抗热震层其应力最大。BSAS+ScYSZ复合涂层应力最小、相稳定、抗水淬能力最强。

Preparing environment barrier coatings was an effective method to protect C/SiC composites under high temperature. In this study, BaO-SrO-A12 03-SiO2 （ BSAS）, ZrO2-Y2 03 （YSZ） , Sc2 03-zrO2-Y2 03 （ SeYSZ ） powders were prepared with chemical co- deposition method, and then three different thermal shock （water quenching） resistance coatings were sprayed on C/SiC composites u- sing the same air plasma spray parameters. The design of coatings, water quenching resistance of 0.2 mm coatings, water quenching resistance of four kinds of thickness and failure mechanisms were investigated. The results indicated that the water quenching resistance of the 0.2 mm thickness coating was in order of ScYSZ （24 cycles） 〉 YSZ （22 cycles） 〉 BSAS （21 cycles） at 1600℃. At the same time, the effects of thickness （including 0.2, 0.3, 0.5 and 0.6 ram） on water quenching resistance were investigated. The results proved that coatings with 0. 2 mm thickness had the best water quenching resistance ability. At the same time, the failure mechanisms were explored. And the results indicated that YSZ coatings had the poorest phase stability and BSAS coatings had the largest inner stress. However, BSAS ＋ ScYSZ composite coatings had the smallest inner stress, excellent phase stability and the best water quench- ing resistance property.