大气等离子喷涂ZrB2/SiC/TaSi2超高温陶瓷涂层及其性能研究

Atmospheric Plasma Spray ZrB2/SiC/TaSi2 Ultra-high Temperature Ceramic Coating and its Properties

高超声速飞行器在飞行过程中面临强烈的气动加热,而C/C复合材料因其优异的高温热稳定性而受到了航天领域的广泛关注,但也存在高温抗氧化能力不足的问题。本文以硼化锆、碳化硅、二硅化钽为原料制备了复合粉体材料,通过大气等离子喷涂(APS)工艺在C/C基体表面制备了高温抗氧化陶瓷涂层;采用SEM、EDS等检测手段对喷雾干燥粉末和涂层的相和微观结构进行了表征,并选用氧乙炔火焰在1800℃下对涂层样品进行了300s烧蚀考核。研究结果表明,TaSi2的加入可以降低复合粉体的共熔温度,在喷涂时粉末可以产生更多的共熔共晶组织,提高粉末沉积效率;采用大气等离子喷涂制备得到的ZrB2/SiC/TaSi2复合陶瓷涂层表现出了优异的高温抗氧化性能,涂层无明显剥落破碎等现象;烧蚀过程中TaSi2可以促进稳定的共晶氧化物的形成以及补充挥发的玻璃相,涂层表面形成了致密的Zr-Ta-O共晶氧化物,起到阻氧屏障的作用,从而使涂层具有更好的抗烧蚀性能。

Hypersonic vehicles face intense aerodynamic heating during flight,and C/C composites have received widespread attention in the aerospace field because of their excellent high-temperature thermal stability,but there is also a problem of insufficient high-temperature oxidation resistance.In this paper,composite powder materials were prepared using zirconium boride,silicon carbide,and tantalum disilicide as raw materials.A high temperature anti-oxidation ceramic coating was prepared on the surface of the C/C substrate by atmospheric plasma spraying(APS)process.SEM,EDS and other tests were employed,the phase and microstructure of the spray-dried powder and coating were characterized,and the oxyacetylene flame was used to test the coating sample at 1800℃for 300 seconds.The research results show that the addition of TaSi2 can reduce the eutectic temperature of the composite powder and more eutectic structure has been formed during spraying.Meanwhile,the powder deposition efficiency has been improved.The ZrB2/SiC/TaSi2 ceramic composite coatings prepared by atmospheric plasma spraying shows excellent high-temperature oxidation resistance and no obvious flaking andbreaking can be observed. TaSi2 can promote the formation of stable eutectic oxide and supplement the volatilizedglass phase during the ablation process. The dense Zr-Ta-O eutectic oxide has been formed and plays a role as anoxygen barrier, thus leads to the better ablation resistance of the coatings.