放电等离子烧结SiC／BN复相陶瓷的制备及力学性能  

Preparation and Mechanical Properties of SiC/BN Multiphase Ceramics via Spark Plasma Sintering

作　　者：翟凤瑞[1,2] 单科[2] 谢志鹏[3] 孙加林[1] 易中周[2] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]红河学院理学院,云南蒙自661199 [3]清华大学,新型陶瓷与精细工艺国家重点实验室,北京100084

出　　处：《硅酸盐学报》2016年第6期866-871,共6页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(51362011和51562009)资助

摘　　要：以高纯h-BN和SiC纳米粉体为原料、B_2O_3为烧结助剂,利用放电等离子烧结技术(SPS)快速烧结制备了h-BN–25%SiC复相陶瓷。用X射线衍射和扫描电子显微镜对试样的物相组成和显微结构进行分析,研究了h-BN–SiC复相陶瓷的SPS低温烧结行为及烧结温度对烧结试样的致密度、微观结构及力学性能的影响。结果表明:采用SPS烧结技术,在较低温度下即可获得致密度较高的烧结样品,烧结温度的升高,促进了h-BN晶粒的方向性排列,提高了烧结样品的相对密度。随着烧结温度的提高,晶粒尺寸增大,抗弯强度、断裂韧性和弹性模量增大,并具有相同的变化趋势。样品晶粒细小均匀,不同烧结温度样品的断裂方式相同,主要为沿晶断裂,细小SiC颗粒的钉扎效应、晶粒拔出和裂纹偏转提高了复相陶瓷的断裂强度和断裂韧性。在1 600℃烧结所得试样的综合性能较好,其抗弯强度、断裂韧性和弹性模量分别为289.2 MPa、3.45 MPa·m1/2和150.9 GPa。The h-BN-25%SiC multiphase ceramics were prepared via spark plasma sintering （SPS） using h-BN and SiC nanopowders as raw materials and B203 as a sintering aid. The phase composition and microstructure were characterized by X-ray diffraction and scanning electronic microscopy. Furthermore, the sintering behavior and the effect of sintering temperature on the densification, microstrueture and mechanical properties of h-BN-SiC multiphase ceramics were investigated. The results show that the high density of the ceramics can be reached at a relatively low temperature in the SPS Process. The directional arrangement of h-BN grains promotes, and the density, grain size and mechanical properties （i.e., flexural strength, fracture toughness and elastic modulus） increase with increasing the sintering temperature. The increased fracture toughness is attributed to the intergranular fracture mode and h-BN grains, which cause crack deflection, grain pullout and the pinning effect of fine SiC particles. The flexural strength, fracture toughness and elastic modulus of the sample sintered at 1 600 ℃ are 289.2 MPa, 3.45 MPa.min and 150.9 GPa, respectively, which are better than those of other samples.

关 键 词：六方氮化硼 碳化硅 放电等离子烧结 烧结行为 致密化 力学性能 

分 类 号：TQ174.75[化学工程—陶瓷工业]