陶瓷矿物改性MoSi2发热元件的组织结构和性能

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.

Microstructure and properties of an MoSi2 heating element modified by ceramic compound

An MoSi_2 heating element was prepared by powder metallurgy with MoSi_2 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 MoSi_2 was the major phase accompanied by small fraction of Mo_5Si_3 and ceramic compound. Adding ceramic compound could obviously activate the sintering of MoSi_2 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 SiO_2 and less MgO, CaO, Na_2O, Al_2O_3 was produced by oxidation at high temperature of electric current.