摘要
以α-Si3N4粉末为原料、Al2O3–RE2O3(RE=Lu,Y,Gd和La)为烧结助剂,在1 800℃压烧结制备氮化硅陶瓷,研究了不同烧结助剂对材料的相组成、微观结构和力学性能的影响。结果表明:样品中α-Si3N4完全转化为β-Si3N4,所形成的长柱状晶粒生长发育良好。随着稀土阳离子半径的增大,材料的相对密度和力学性能呈增加趋势,其中Si3N4–Al2O3–Gd2O3的抗弯强度和断裂韧性分别达到860 MPa和7.2 MPa·m^1/2。由于稀土离子对烧结液相黏度的影响,Si3N4–Al2O3–Lu2O3和Si3N4–Al2O3–Y2O3中出现了晶粒异常长大的现象,而Si3N4–Al2O3–La2O3的基体与柱状晶粒界面结合较大导致材料力学性能降低。
Silicon nitride ceramics were prepared via hot-pressing at a sintering temperature of 1800℃withα-silicon nitride as a raw material and Al2O3–RE2O3(RE=Lu,Y,Gd and La)as sintering additives.The effect of sintering additives on the phase composition,microstructure and mechanical properties of silicon nitride ceramics was investigated.The results show thatα-Si3N4 in the sample can completely convert toβ-Si3N4 with long columnar grains.The relative density and mechanical properties of the material increase with the increase of the rare-earth element ion radius,and the flexural strength and fracture toughness of Si3N4–Al2O3–Gd2O3 are 860MPa and 7.2 MPa m^1/2,respectively.Due to the effect of rare earth element ions on the viscosity of the sintered liquid phase,the growth of exaggerated grains occurs in the samples of Si3N4–Al2O3–Lu2O3 and Si3N4–Al2O3–Y2O3,and Si3N4–Al2O3–La2O3 has a strong grain interface bonding between the matrix and columnar grain,leading to the reduction of their mechanical properties.
作者
李天峰
陈拥军
李建保
余辉
李崴
徐智超
骆丽杰
LI Tianfeng;Chen Yongjun;LI Jianbao;LUO Lijie;YU Hui;LI Wei;XU Zhichao(State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering, Hainan University, Haikou 570228, China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2019年第6期796-802,共7页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金(51702072)
国家高技术研发发展计划(863计划)(2015AA034103)
关键词
氮化硅
稀土氧化物
微观结构
力学性能
silicon nitride
rare earth oxide
microstructure
mechanical properties
