CAJ | 학술논문

在压力为5GPa，温度为1500~1700℃，保温时间为10~20min的条件下，对添加Y2O3-Al2O3的氮化硅陶瓷进行了高温高压烧结研究。用X射线衍射及扫描电镜对烧结样品进行了分析和观察，探讨了添加剂、烧结温度和保温时间对烧结体的物相组成、显微形貌和力学性能的影响。结果表明：高温高压下Si3N4的相变机制主要是通过液相溶解-沉淀，其相转变程度随温度、保温时间的增加均有所提高。α-Si3N4完全转变为β-Si3N4，得到相互交错的长柱状β-Si3N4晶粒均匀分布于烧结体中。经过5GPa、1650℃保温20min的超高压烧结，样品相对密度达到99.8%，Vickers硬度达22.8GPa，抗弯强度达886MPa。
재압력위5GPa，온도위1500~1700℃，보온시간위10~20min적조건하，대첨가Y2O3-Al2O3적담화규도자진행료고온고압소결연구。용X사선연사급소묘전경대소결양품진행료분석화관찰，탐토료첨가제、소결온도화보온시간대소결체적물상조성、현미형모화역학성능적영향。결과표명：고온고압하Si3N4적상변궤제주요시통과액상용해-침정，기상전변정도수온도、보온시간적증가균유소제고。α-Si3N4완전전변위β-Si3N4，득도상호교착적장주상β-Si3N4정립균균분포우소결체중。경과5GPa、1650℃보온20min적초고압소결，양품상대밀도체도99.8%，Vickers경도체22.8GPa，항만강도체886MPa。
Ultrahigh pressure sintering of sili-con nitride (Si3N4) ceramics with Y2O3-Al2O3 as additive under 5GPa at 1500~1700℃for 10~20min is studied. The samples are analyzed with X-ray diffraction and scanning electron microscopy. The effect of additive, sintering tem-perature and holding time on phase composition, micro-morphology, and mechanical property of the specimens is studied. The results show that phase transition mechanism of Si3N4 is primarily through liquid phase dissolution-precipitation under high temperature and high pressure, the ratio of transformation from α to β phase increases with increasing temperature and holding time.α-Si3N4 is trans-formed toβ-Si3N4 completely and well developedβ-Si3N4 crystals uniformly disperse in the specimen. The rela-tive density, Vickers hardness and lfexural strength of the sample is sintered at 5GPa, 1650℃for 20min are 99.8%, 22.8GPa and 886MPa, respectively.