为了提高C/SiC复合材料的超高温抗烧蚀性能,以锆粉、硼粉和酚醛树脂为原料,通过泥浆涂刷后高温烧结的方法在C/SiC表面制备了ZrB2涂层,研究了涂层的烧结反应过程,并对其组成、结构和抗烧蚀性能进行了表征.结果表明:1200℃前Zr先与碳反应生成ZrC,然后在1400~1600℃时ZrC与B反应生成ZrB2.浆料配比为n(Zr):n(B):n(C)=1.0:1.5:1.0时,1600℃制备的涂层由ZrB2、少量的ZrC及ZrO2组成.氧乙炔焰烧蚀60s后,由于ZrB2氧化形成了ZrO2熔融层,涂层后的C/SiC复合材料的线烧蚀率几乎为零,而未涂层的C/SiC复合材料的线烧蚀率为0.064mm/s.
In order to improve the ablation property of C/SiC composite at ultra high temperatures,ZrB2 coatings upon C/SiC composite were prepared by pasting the slurry of zirconium powder,boron powder and phenolic resin,followed by high temperature sintering.The reactions in the sintering process were investigated,and the component,microstructure and ablation property of the coatings were characterized.The results show that zirconium powder reacts firstly with pyro-lytic carbon to form ZrC till 1200℃,and then ZrC reacts with boron to form ZrB2 during 1400℃-1600℃.When the mole ratio of Zr/B/C is 1.0/1.5/1.0,the coating sintered at 1600℃ is composed of mainly ZrB2,small amount of ZrC and ZrO2.After ablation for 60 s in oxyacetylene torch environment,the C/SiC composite with ZrB2 coating shows a linear reces-sion rate of zero,due to the ZrO2 formation from ZrB2 oxidation,while the C/SiC composite without coating shows a lin-ear recession ratio of 0.064mm/s.