以自蔓延高温合成的MoSi2和陶瓷矿物为原料,通过粉末冶金工艺制备了MoSi2发热元件,采用XRD,SEM和EDS等技术分析了MoSi2发热元件的微观组织结构和性能.结果表明:MoSi2发热元件的主要成分为MoSi2,Mo5Si3和陶瓷矿物.加入陶瓷矿物明显活化了MoSi2的烧结,降低了MoSi2的烧结温度,阻止了MoSi2晶粒的过度长大,使得发热元件具有比较均匀的组织结构以及较高硬度和断裂韧性.通电氧化可以使MoSi2发热元件表面生成一层以SiO2为主的含有少量MgO,CaO,Na2O,Al2O3等物质的玻璃相,提高了元件表面保护膜的稳定性.
An MoSi2 heating element was prepared by powder metallurgy with MoSi2 powder synthesized by self-propagating high temperature synthesis (SHS) and ceramic compound as the starting materials. Its microstructure and properties were tested by XRD and SEM with EDS. The results indicated that MoSi2 was the major phase accompanied by small fraction of Mo5Si3 and ceramic compound. Adding ceramic compound could obviously activate the sintering of MoSi2 and reduce its sintering temperature and retard the over growth of grains. The hardness and fracture toughness were also improved. A glass scale with high content SiO2 and less MgO, CaO, Na2O, Al2O3 was produced by oxidation at high temperature of electric current.