碳基钨涂层在退火过程中的组织和结构变化

Microstructure and Texture Changes of Tungsten-Coated Carbon/Carbon Fiber Composite During Annealing

用真空等离子体喷涂 (VPS)技术在C/C复合材料基体上制备了厚度为 0 5mm的钨 (W )涂层 ,涂层的表面通过物理气相沉积 (PVD)预沉积钨、铼 (Re)多层作为碳 (C)的扩散势垒。涂层经过 12 0 0℃～ 2 0 0 0℃的电子束退火 ,其微观结构和化学构成发生变化。经测量涂层的再结晶温度约为 14 0 0℃ ,再结晶的活性能为6 3kJ/mol。当退火温度高于 130 0℃时 ,涂层表面的多层W、Re结构将由于W、Re和C之间的相互扩散而发生改变 ,并在 16 0 0℃以上退火 1h后由于脆性碳化钨在界面的形成而完全失效 ,碳化钨层的厚度将随着退火温度的升高和退火时间的延长而迅速增加。

The 0.5 mm thickness tungsten coating on CFC(CX-2002U)with multi-layer interface of tungsten(W)and rhenium(Re)pre-deposited by physical vapor deposition(PVD)was prepared by vacuum plasma spraying(VPS) and its microstructure and texture changes were examined by 1200℃～2000℃ annealing in an electron beam thermal load facility.It is showed that the recrystallization temperature of VPS-W coating is about 1400℃ and the corresponding activation energy of recrystallization is estimated as 63 kJ/mol.The structure of the multi-layers of W and Re is varied with the mutual diffusion of W,Re and C above 1300℃.Due the diffusion barrier consisted of these W and Re multi-layers became failure after annealing over 1600℃ for one hour to the formation of brittle tungsten carbides at the interface.Furthermore,the thickness of tungsten carbides increase rapidly with increasing annealing temperature and time.