烧结温度对气压烧结氮化硅铁显微结构及性能的影响  

Effect of Sintering Temperature on Microstructure and Properties of Gas Pressure Sintered Ferrosilicon Nitride

作　　者：管甲锁 成来飞[1] 王耀辉[1,3] 李明星 张立同 

机构地区：[1]西北工业大学,超高温结构复合材料国防科技重点实验室,西安710072 [2]西安澳秦新材料有限公司,西安710032 [3]内蒙合成化工研究所,呼和浩特010010

出　　处：《硅酸盐学报》2017年第12期1818-1824,共7页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金重点项目(51632007)资助

摘　　要：以微米级氮化硅铁为原料、Al_2O_3–Y_2O_3为烧结助剂,采用气压烧结制备氮化硅铁复相陶瓷。通过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了表征,研究了烧结温度对氮化硅铁复相陶瓷成分、显微结构和力学性能的影响。结果表明:烧结温度对于氮化硅铁陶瓷的显微结构和力学性能具有显著影响。随着烧结温度的升高,样品致密度、抗弯强度、断裂韧性先增大后降低,在1 770℃时均达到最大值,密度、抗弯强度和断裂韧性分别达到3.31 g/cm^3、435 MPa和6.97 MPa?m^(1/2)。在1 770℃以下时,陶瓷样品中主晶相为长柱状的β-Si3N4,晶粒彼此间结合紧密,陶瓷气孔率较低。温度继续升高,含铁相和氮化硅发生反应,气孔率增大,抗弯强度和断裂韧性开始下降。如果进一步提高硅铁的氮化率,采用游离硅低、铁含量低及纯度较高的氮化硅铁粉末制备氮化硅铁陶瓷,材料的性能有望得到进一步的提高。Ferrosilicon nitride ceramics were fabricated via gas pressure sintering（GPS） using micron sized ferrosilicon nitride as a raw material and Al2O3–Y2O3 as sintering aids. The phase composition and microstructure of the specimens were analyzed by X-ray diffraction and scanning electronic microscopy, and the effect of sintering temperature on the microstructure and mechanical properties of ferrosilicon nitride ceramics was investigated. The results show that β-phase ferrosilicon nitride ceramic with a high density and good mechanical properties can be obtained by GPS. The density, flexural strength and fracture toughness of the samples firstly increase and then decrease with increasing the sintering temperature. The highest density, flexural strength and fracture toughness of the samples sintered at 1 770 ℃ are 3.31 g/cm^3, 435 MPa and 6.97 MPa？m^（1/2）, respectively. Below 1 770 ℃, the main crystal phase is elongated columnar β-Si3N4, which is uniform and well-developed. The compact connection between the grains results in the less pores of grain boundaries. The reactions of iron containing phase and silicon nitride occur as sintering temperature further increases, leading to the increase of porosity and the decrease of flexural strength and fracture toughness. The non-nitrided iron-rich particles exist in the sintered bodies, which could be removed for the further increase of the mechanical properties of Fe-Si3N4 ceramic.

关 键 词：氮化硅铁 气压烧结 显微结构 力学性能 

分 类 号：TQ174[化学工程—陶瓷工业]