CAJ | 학술논문

将粒径为30～35 nm的β-SiC粉，加入亚微米尺寸的α-Al2O3粉料中，通过无压烧结工艺，制备出了Al2O3/SiC纳米复相陶瓷. 烧结体相对密度达到98.82%，抗弯强度和断裂韧性分别达到489 MPa和6.67 MPa*m1/2. SEM分析发现：纳米SiC颗粒镶嵌于氧化铝晶界，形成了由Al2O3-SiC-Al2O3晶粒间搭桥联结的界面与SiC-Al2O3之间牢固结合的相界组成的复合界面，改善了晶界结构，极大地提高强度和韧性. 同时发现纳米强化相中O2含量对烧结体密度和组织结构有重要影响. 用Si/C/N非晶复合粉作为强化相也进行了对比实验.
장립경위30～35 nm적β-SiC분，가입아미미척촌적α-Al2O3분료중，통과무압소결공예，제비출료Al2O3/SiC납미복상도자. 소결체상대밀도체도98.82%，항만강도화단렬인성분별체도489 MPa화6.67 MPa*m1/2. SEM분석발현：납미SiC과립양감우양화려정계，형성료유Al2O3-SiC-Al2O3정립간탑교련결적계면여SiC-Al2O3지간뢰고결합적상계조성적복합계면，개선료정계결구，겁대지제고강도화인성. 동시발현납미강화상중O2함량대소결체밀도화조직결구유중요영향. 용Si/C/N비정복합분작위강화상야진행료대비실험.
β-SiC nanometer powder with the mean particle size of 30～35 nm, as the strengthening phases, was added into α-Al2O3 powder with the mean particle size of 0.37 μm. The pressureless sintering technology was used to prepare the Al2O3/SiC nanocomposite ceramics. The experimental results show that the relative density of the sintered body can reach 98.82%, and the flexural strength and the fracture toughness reach 489 MPa and 6.67 MPa*m1/2 respectively. The microstructure was observed by means of SEM. It has been found that the grain boundary structure of alumina ceramics consists of both the bridge of“ Al2O3-SiC-Al2O3”and the phase boundary of “SiC-Al2O3”, forming firmly combined composite boundary. This composite boundary raises the strength of the grain boundary, and limits the crack producing and growing only within the grain. The fracture mode is transformed from brittle intergranular fracture to intragranular fracture. Both the sub_structure and nano SiC particles within the grain can slow down the growing speed of cracks and increase strength and toughness greatly. The amount of O2　existing in nanopowder can bring serious influence to the properties and microstructure of the sintered body. The contrast test that utilizing Si/C/N amorphous compound powder as the strengthening phases was done, too.