不同显微结构Yb_(2)Si_(2)O_(7)环境障涂层的抗热震性能研究  

Research on Thermal Shock Resistance of Yb_(2)Si_(2)O_(7) Environmental Barrier Coatings with Different Microstructures

作　　者：张朋贵 冀晓鹃 侯伟骜 卢晓亮 Zhang Penggui;Ji Xiaojuan;Hou Weiao;Lu Xiaoliang(BGRIMM Technology Group,Beijing 100160;Beijing Engineering Technology Research Center of Surface Strengthening and Repairing of Industry Parts,Beijing 102206;Beijing Key Laboratory of Special Coating Materials and Technology,Beijing 102206;BGRIMM Advanced Materials Science&Technology Co.,Ltd)

机构地区：[1]矿冶科技集团有限公司,北京100160 [2]北京市工业部件表面强化与修复工程技术研究中心,北京102206 [3]特种涂层材料与技术北京市重点实验室,北京102206 [4]北矿新材科技有限公司,北京102206

出　　处：《热喷涂技术》2021年第4期23-34,共12页Thermal Spray Technology

基　　金：国家科技重大专项(2017-VI-0020-0093)。

摘　　要：采用低压等离子喷涂工艺(LPPS)在SiC_(f)/SiC复合材料表面依次制备了Si底层、Mullite中间层和Yb_(2)Si_(2)O_(7)面层的环境障涂层。通过不同的喷涂参数分别制备出层状结构和层柱混合结构的Yb_(2)Si_(2)O_(7)面层,并考察面层结构对环境障涂层抗热震性能的影响。结果表明,所制备的两种面层涂层均具有孔隙率低、界面结合紧密的特点,层柱混合结构的面层中柱状结构为Yb_(2)Si_(2)O_(7)气化所形成,而层状结构为液相沉积所形成。X射线衍射分析结果显示,层状涂层结晶良好,而层柱混合结构涂层中存在大量的非晶态。对非晶态进行热处理可得到结晶完全的层柱混合结构涂层。热震实验结果表明,层状涂层经355次热震后脱落面积很小,表现出良好的抗热震性能。相比之下,非晶态层柱混合结构涂层经热震3次后即出现脱落,经155次热震后脱落面积达到5%,抗热震性能较差。晶态的层柱混合结构涂层经热震20次后出现脱落,随后脱落速度减缓,但到第40次热震时,涂层大块脱落加速失效。The environmental barrier coatings of Si(bottom layer),Mullite(middle layer),and Yb_(2)Si_(2)O_(7)(surface layer)were sequentially prepared on the surface of SiC_(f)/SiC composites by low-pressure plasma spraying process(LPPS).Two types of Yb_(2)Si_(2)O_(7)surface layers with layered structure and layer-column mixed structure were deposited via adjusting spraying parameters.The effects of Yb_(2)Si_(2)O_(7)microstructure on thermal shock resistance of the environmental barrier coatings were investigated.The results showed that both the Yb_(2)Si_(2)O_(7)coatings prepared by LPPS exhibited low porosity and tight interface bonding.The columnar structure in the surface layer of the layer-column mixed structure is formed by Yb_(2)Si_(2)O_(7)gasification,and the layered structure is formed by liquid deposition.X-ray diffraction analysis results showed that the layered coating had good crystallization,while a large amount of amorphous state existed in the layer-column mixed structure coating,which can be heat-treated to obtain a fully crystalline coating.The thermal shock test results showed that the layered coating has a small shedding area after 355 thermal shocks,showing good thermal shock resistance.In contrast,the amorphous layer-column hybrid structure coating appeared to fall off after 3 thermal shocks,and the fall-off area reached 5%after 155 thermal shocks,which meant that the thermal shock resistance was poor.The crystalline layer-column hybrid structure coating appeared to fall off after 20 thermal shocks,and then the rate of fall off slowed down,but by the 40th thermal shock,the coating fell off in large chunks and accelerated to failure.

关 键 词：环境障涂层 低压等离子喷涂 硅酸镱 层状结构 抗热震性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]