FABRICATION AND PROPERTIES OF OXIDATION RESISTANCE OF C/C COMPOSITE USING BORIDE CERAMICS LAYER

空间技术的进步需要空间应用耐久的材料。因此，可用的陶瓷材料根据特性受到限制，使用条件也被细分。硅的氧化物、碳化物和氮化物的化合物是有用的工业材料。SiB_4、SiB_6、SiB_6+x、SiB_6-x、<14>SiB_4、Si_8. <44>B_<305.51>和Si B_<31>，以前曾报道过。其中，六硼化硅（SiB_6）由于其优异的化学稳定性而被证明是一种潜在的有用材料。碳纤维增强碳复合材料（C/C复合材料）在1750 K以上的高温下具有优异的比强度。它的材料已经显示出应用于由碳组成的C/C复合材料中的纤维和基体，这使得其材料在氧化气氛存在下在800 K以上的温度下具有强烈的抗氧化性。本研究通过在C/C复合材料表面包覆SiB_6制备C/C复合材料，研究了SiB_6粉末、SiB_6烧结体和SiB_6包覆C/C复合材料的高温氧化行为，以确定其高温实用性。研究了硼化物覆盖C/C复合材料的抗高温氧化性能，以确定该复合材料在高温工程应用中的适用性。采用浸渍法将SiB_6粉末分散到三甘醇中，对C/C复合材料进行表面包覆，以提高其抗氧化性能。以相当于总质量的约2%至4%的附加质量获得C/C复合材料样品，并且其样品的表面未经其处理而涂覆有C/C复合材料。C/C复合材料的高温抗氧化性能显著提高。

Materials endurable for space applications will be required for space advancements. Therefore, the useful ceramic materials is limited in compliance with the characteristic and the conditions of the use are also subdivided. Silicon chemical compound of oxide, carbide and nitride is the useful industrial materials. Several silicon boride phases such as SiB_4, SiB_6, SiB_6+x, SiB_6-x, SiB_<14>, Si_8._<44>B_<305.51> and SiB_<31>, were previously reported. Among them, silicon hexaboride (SiB_6) has proved to be a potentially useful material because of its excellent chemical stability. The carbon fiber reinforced carbon composite (C/C composite) has excellent specific strength at high temperature over 1750 K. Its material has shown use for the application to the fiber and matrix in the C/C composite consists of carbon, which causes its material to oxidation resistance intensely under the presence of oxidation atmosphere at temperature of more than 800 K. We made C/C composite that SiB_6 covered the surface of C/C composite.In this study, the oxidation behavior at high temperature of the SiB_6 powder, SiB_6 sintered body and SiB_6 covered C/C composite were investigated in order to determine its high-temperature utility. The temperature oxidation resistance of the boride covered C/C composite was investigated in order to determine the suitability of this composite for high temperature engineering applications. The aim of this study was to give the resistance oxidation performance to the surface of C/C composite covered with SiB_6 powder were dispersed to a triethyleneglicol using the dipping process in order to coat this sample. The C/C composite samples were obtained with additional mass equal to about 2 to 4 % of the total mass, and surface of its sample was coated with the C/C composite material without its process. The high temperature oxidation resistance of C/C composite drastically improved by covered boride films.