摘要：本文以UBE氮化硅、国产氮化硅为原料，Y2O3和MgO为烧结助剂，利用放电等离子烧结（SPS）技术制备氮化硅陶瓷。通过排水法测密度，扫描电镜对试样的物象组成和显微结构进行分析，研究了烧结温度对氮化硅陶瓷力学性能和显微结构的影响。并对试样的热导率进行测定。发现了采用SPS烧结技术可以获得致密度较高，力学性能较好的氮化硅陶瓷。随着温度的提高，样品的致密度、抗弯强度、断裂韧性均随之增大。在1650度时，致密度达到最高3.22g/cm3。在1700℃时，其抗弯强度和断裂韧性分别达到910.64MPa和9.04MPa·m1/2。采用SPS烧结的氮化硅陶瓷在高温下显微结构均匀，晶粒发育良好、呈长柱状，晶间紧密相连，晶间气孔较少。71098

毕业论文关键词：放电等离子烧结；氮化硅；烧结温度；力学性能；热导率；显微结构。

High thermal conductivity Silicon Nitride Ceramics by Spark Plasma Sintering

Abstract：The high-performance silicon nitride ceramics were prepared via spark plasma sintering (SPS) with UBE powder of silicon nitride as a raw material and Y2O3 、MgO as a sintering aid. The density is measured by drainage，The phase constitution and microstructure of specimenswere analyzed by X-ray diffraction and scanning electronic microscopy. The effect of sintering temperature on the microstructure and mechanical properties of silicon nitride ceramics were investigated. The results show that β-phase silicon nitride ceramic with a high

density and good mechanical properties can be obtained at a lower sintering temperature by SPS. The density, flexural strength and fracture toughness of the samples improve with the increase of the sintering temperature. The flexural strength and fracture toughness of the samples sintered at 1700 ℃ are 910.64MPa and 9.04 MPa·m1/2, respectively. According to the phase composition and microstructure analysis, the β-phase content of silicon nitride ceramics is 98%. The elongated columnar silicon nitride grains are uniform and well-developed. The compact connection between the grains results in the less pores of grain boundaries. 

目录

1 绪论 1

1.1 Si3N4简介 1

1.1.1 Si3N4的结构及性能 1

1.1.2 Si3N4的热导率 3

1.1.3 Si3N4的粉体制备方法 3

1.1.4 Si3N4的烧结方法 4

（1） 反应烧结 4

（2） 热压烧结 4

（3） 常压烧结 4

（4） 气压烧结 5

1.2 放电等离子烧结技术（SPS） 5

1.2.1 SPS简介 5

1.2.2 SPS装置构成 5

1.2.3 SPS烧结原理 5

1.2.4 SPS烧结的工艺优势 5

1.2.5 SPS烧结技术在国内外的发展及应用 6

1.2.6 结语 7

1.3 选题意义及主要研究内容 7

2实验制备工艺 9

2.1 实验材料 9

2.1.1 主要原材料 9

2.1.2 材料配比 10

2.2 实验设备 10

2.3 实验方法 10