论文部分内容阅读
在铁铬铝电热合金中加入0.038%镧铈混合稀土或0.49%钇与不加稀土金属的共三种试样,进行快速寿命和氧化动力学的对比试验,对氧化后试样氧化膜的形态和粘附性进行了金相观察。X射线衍射分析结果发现:含钇的试样在1200℃经350小时氧化后,在氧化膜的内层存在一个新相。初步鉴定这一新相是钇铝石榴石(Y_3Al_5O_(12)),它与氧化膜粘附性的明显改善有着直接的关系。铁铬铝合金在高温下长时间停留,晶粒迅速长大,力学性能急剧降低。稀土金属特别是钇的加入,有效地阻止晶粒长大,显著地减缓力学性能的降低,这可能是稀土元素能够大幅度提高铁铬铝电热丝快速寿命值的主要原因。
In iron-chromium-aluminum alloy, 0.038% lanthanum cerium mixed rare earth or 0.49% yttrium plus no rare earth metal was added to compare the fast life and oxidation kinetics. The morphology of oxide film And adhesion were observed metallographically. X-ray diffraction analysis showed that the yttrium-containing sample had a new phase in the inner layer of the oxide film after being oxidized at 1200 ° C for 350 hours. Preliminary identification of this new phase is yttrium aluminum garnet (Y_3Al_5O_ (12)), which is significantly improved with the adhesion of oxide film has a direct relationship. Iron-chromium aluminum alloy at a high temperature for a long time to stay, the rapid growth of grains, a sharp decrease in mechanical properties. The addition of rare earth metals, especially yttrium, can effectively prevent grain growth and significantly slow down the reduction of mechanical properties, which may be the main reason that rare earth elements can greatly improve the fast life of iron-chromium aluminum heating wire.