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采用聚碳硅烷(PCS)作为先驱体,通过浸渍裂解法制备C/C-SiC材料,分别经过1 400、1 500、1 600℃高温处理,研究了不同处理温度对SiC基体的微晶形态及C/C-SiC材料力学性能和抗氧化性能的影响。结果表明,3种处理温度下,SiC的晶型主要为β-SiC。温度升高,晶粒尺寸增大,1 500℃以后生长速度减缓;SiC微晶优先沿着(111)晶面生长,(220)和(311)晶面的生长取向逐渐增加。处理温度升高,C/C-SiC材料的弯曲强度和剪切强度不断下降。1 400℃处理后,C/C-SiC材料的断裂方式呈现出非常明显的韧性断裂。C/C-SiC材料在1 500℃静态空气中的氧化失重率随高温处理温度的升高而逐渐增大,氧化程度越来越严重,断面典型区域的氧化形貌由“尖笋状”成为“梭形”。
Polycrystalline silicon carbide (PCS) was used as precursor to prepare C / C-SiC material by immersion pyrolysis. The microstructure of SiC matrix was investigated by high temperature treatment of 1400, 500 and 600 ℃ respectively. Effect of C / C-SiC on mechanical properties and oxidation resistance. The results show that the crystalline forms of SiC are mainly β-SiC at the three treatment temperatures. With the increase of temperature, the grain size increases and the growth rate slows down after 1 500 ℃. The SiC crystallites preferentially grow along the (111) crystal plane and the growth orientations of (220) and (311) crystal planes increase gradually. With the increase of the treatment temperature, the bending strength and shear strength of C / C-SiC material decrease continuously. After the treatment at 1400 ℃, the fracture mode of C / C-SiC material shows very obvious ductile fracture. The weight loss of C / C-SiC in static air at 1 500 ℃ increased gradually with the increase of the temperature, and the oxidation degree became more and more serious. The oxidation morphology of the C / Becomes “spindle”.