氮化硼掺杂石墨材料的抗氧化性能研究

摘要

Using ultra-fine graphite powders and hexagonal structural BN powders as raw materials and SC coal pitch as a binder, graphite blocks doped with BN powders were prepared by a hot-pressing method. The influence of BN doping content on the oxidative weight loss of doped-graphite at 600℃, 900 ℃ and 1000 ℃ was investigated. The microstructure and morphology of oxidized surface of pure graphite and doped-graphite blocks were analyzed by scanning electron microscopy. The results show that pure graphite blocks possess poor anti-oxidation property, and the anti-oxidation performance of graphite blocks doped by BN powders is obviously improved. The oxidative weight loss of doped-graphite blocks greatly decreases, owing to form B2O3 anti-oxidation protective films with crystalline and glassy structure, which are derived from BN powders through oxidation at a high temperature.%以超细人造石墨粉和六方氮化硼(BN)粉为原料,SC煤沥青为粘接剂,采用热压成型法制备了BN掺杂石墨材料.研究了不同BN含量掺杂石墨材料在中温(600℃)和高温(900℃、1000℃)时的氧化失重行为,并对掺杂石墨材料氧化前后的微观形貌和结构进行了分析.结果表明,纯石墨材料的抗氧化性能较差,掺杂BN后其抗氧化性能得到明显提高,氧化失重大大降低,原因是BN在高温下氧化生成了晶态和玻璃态的氧化硼抗氧化保护膜.