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高温氮化硅材料正在发展成为一种热机和其它高温工程材料,在材料制备中为了得到充分致密的材料需要加入少量添加剂。然而由于添加剂的存在,在制成材料晶界处形成玻璃相,因而氮化硅材料的高温强度、断裂机理和蠕变等力学性能将受到玻璃相影响。虽对有玻璃相存在的氮化硅材料的氧化过程和蠕变及晶界滑移等问题进行了若干研究,但对经高温持久试验后材料中玻璃相变化情况的研究颇少。在文献[1]中已提到掺稀土氧化物的氮化硅的力学性能的影响,并阐明在该材料中添加Al_2O_3与不添加Al_2O_3后对高温强度的影响。
High-temperature silicon nitride materials are evolving into heat engines and other high-temperature engineering materials that require the addition of small amounts of additives in order to obtain a sufficiently dense material during material preparation. However, due to the presence of additives, a glass phase is formed at the grain boundary of the prepared material, so the mechanical properties such as high temperature strength, fracture mechanism and creep of the silicon nitride material will be affected by the glass phase. Although some studies have been made on the oxidation process, creep and grain boundary slip of silicon nitride materials with glassy phase, the research on the glass phase change after long-term high temperature test has been studied. The effect of the mechanical properties of silicon nitride doped with rare earth oxides has been mentioned in [1], and the effect of Al 2 O 3 addition on the high temperature strength without adding Al 2 O 3 has been clarified.