Abstract
To improve the uniformity and the content of HfB2 in HfB2-Si-based ceramic coating and alleviate the damage of substrate,and then enhance the high-temperature(1700℃)oxidation and cyclic ablation resistances of carbon/carbon composites,a close-knit double layer HfB2-SiC/SiC coatings with a mosaic structure and high content of HfB2 were prepared by a novel dipping-carbonization assisted pack cemen-tation methods(DPC-HS/S).In contrast,a HfB2-SiC/SiC coatings were also fabricated by pack cementa-tion(PC-HS/S).Results revealed that the oxidation and ablation protective performances of the DPC-HS/S coatings were superior to those of PC-HS/S coatings.After 30 thermal cycles between 1500℃and room temperature,the mass gain of the coated sample was 0.78％,and the mass loss was 1.65％after oxidation at 1700℃for 156 h.Moreover,under an oxyacetylene torch ablation for 180 s(3 cycles),the linear abla-tion rate of the DPC-HS/S coated specimen was 1.62 um/s,which was much lower than that of PC-HS/S coated specimen(3.08μm/s).
基金项目
国家自然科学基金(51872239)
国家自然科学基金(52061135102)
国家自然科学基金(52002321)
Creative Research Foundation of Science and Technology on Thermostructural Composite Materials Laboratory(5050200015)
Fundamental Research Funds for the Cen-tral Universities(G2020KY05125)
Xi'an Association for Science and Technology"Young Talent Support Project"(095920211338)
Analytical&Testing Center of Northwestern Polytechnical University(NWPU)()
NETL
NSTL
万方数据