摘要
以MgO-Al2O3-SiO2体系作为烧结助剂,研究了氮化硅陶瓷的无压烧结。着重考察了烧结温度、保温时间以及烧结助剂用量等工艺因素对氮化硅陶瓷材料力学性能和显微结构的影响,通过工艺调整来设计材料微观结构以提高材料的力学性能。在烧结助剂质量分数为3.2％的情况下,经1 780℃,3 h无压烧结,氮化硅大都呈现长柱状β-Si3N4晶粒,具有较大的长径比,显微结构均匀。样品的相对密度达99%,抗弯强度为956.8 MPa,硬度HRA为93,断裂韧性为6.1 MPa·m1/3。具有较大长径比晶粒构成的显微结构是该材料表现较高力学性能的原因。
Pressless sintering of silicon nitride ceramics with MgO-A12O3-SiO2 as additives was studied. The effects of sintering temperature, soaking time and additives content on the mechanical properties and microstructure of silicon nitride ceramics were systematically investigated in order to obtain materials with desired microstructure and mechanical properties. Silicon nitride ceramics with 3.2% (in mass) additive sintered at 1780°C for 3 h is mainly composed of elongated β-Si3N4 grains with relative density of 99%, flexure strength of 956.8 MPa, hardness HRA of 93, and fracture toughness of 6.1 Mpa·m1/2. The promising mechanical properties of the sample are attributed to the HRA uniform microstructure of grains with bigger aspect ratio.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2004年第2期139-143,共5页
Journal of The Chinese Ceramic Society
基金
上海市科技攻关(0152nm031
015211068)
国家973基础研究(G2000067204-2)资助项目
关键词
氮化硅
力学性能
显微结构
无压烧结
Additives
Bending strength
Crystal microstructure
Fracture toughness
Hardness
Mechanical properties
Silicon nitride
Sintering
