论文总字数：20590字

摘 要

SiC-AlN复相材料是重要的微波衰减陶瓷。一般情况下要想制得致密的复相材料均采用热压烧结。但是由于热压烧结工艺流程复杂，生产效率低，生产出的制品形状简单，因此限制了其应用，所以无压烧结逐渐成为研究的重点。

本文主要阐述了SiC和AlN的性质、SiC-AlN复相陶瓷的烧结工艺以及SiC基复相陶瓷的研究进展。本课题旨在采用掺入助烧剂的方式来降低无压烧结的温度，以烧制出致密化的SiC-AlN复相陶瓷；并对于助剂的种类及含量对材料的烧结性能、物相组成、断面显微结构、导热性能以及抗弯强度所产生的影响进行分析。

本文通过实验测试，发现在氩气氛围中，1850 ℃下保温1 h，烧制出的SiC-AlN(质量比为1:1)复相陶瓷中，Y₂O₃-SiO₂助剂(摩尔比为2.9:7.1)对复相材料致密性的改善比Y₂O₃-SiO₂-Al₂O₃助剂(质量比为3.19:2.13:4.68)的效果更好；而且当烧结助剂含量逐渐增加的时候，复相材料的致密性和抗弯强度均得到提高和改善，而导热性能呈现出先上升后下降的趋势。当助剂Y₂O₃-SiO₂的含量达到12 wt%时，材料的各项性能均达到最好。可以烧制出体积密度为3.21 g/cm³，显气孔率为0.15%，晶粒大小均匀，抗弯强度为354.57 MPa以及热导率为42.96 W·m^-1·K^-1的SiC-AlN复相材料。

关键词：SiC-AlN 无压烧结 致密性 导热性能 抗弯强度

ABSTRACT

SiC-AlN composites was an important microwave attenuation materials. Producing fully dense composite materials were used hot pressing sintering under normal circumstances. But the widespread use of the hot-pressing sintering technique had been restricted due to the complex process, the simple shape of the products and the low production efficiency. So pressureless sintering technique has gradually become a hot spot in current research.

This paper mainly expounded SiC and AlN properties, the sintering processes of SiC-AlN composite ceramics, the research progress of SiC matrix composite ceramics. This subject was aimed at reducing the pressureless sintering temperature of the compact SiC-AlN composite ceramics by adding sintering additives. It was studied on the fluence of types and contents of sintering additives to sintering properties, phase composition, microscopic structure of the cross section, thermal conductivity and bending strength of SiC-AlN composite ceramics.

This paper through experimental tests had found that Y₂O₃-SiO₂ (which mole ratio was 7.1:2.9) additives was better than Y₂O₃-Al₂O₃-SiO₂ (which mass ratio was 3.19: 2.13: 4.68) additives for SiC-AlN (which mass ratio was 1: 1) multiphase ceramics composites, under the condition of Argon atmosphere, 1850 ℃, 1 hour holding time. And with the increase of sintering additives content, complex phase densification and flexural strength were obtained to improve, and thermal conductivity had showed a trend that increased first and then decreased. When the content of Y₂O₃-SiO₂ additives was 12 wt%, the properties of the materials were all up to the baet. Can burn out the SiC-AlN multiphase ceramics materials which bulk density was 3.205 g/cm³, apparent porosity was 0.15%, uniform grain size , the bending strength was 354.57 MPa and the thermal conductance rate was 4.296 W·m^-1·K^-1 .

Key Words: SiC；AlN；Pressureless sintering；Densification；Thermal conductivity；Bending strength

目 录

摘要 Ⅰ

ABSTRACT Ⅱ

第一章 绪论 1

1.1 引言 1

1.2 SiC陶瓷的性能特点及烧结制备 1

1.2.1 SiC的性能特点及其应用 1

1.2.2 SiC陶瓷的烧结制备 1

1.3 AlN陶瓷的性能特点 2

1.3.1 AlN的性能特点及其应用 2

1.4 SiC-AlN复相陶瓷的研究现状及烧结制备 2

1.4.1 SiC-AlN复相陶瓷的研究现状 2

1.4.2 SiC-AlN复相陶瓷的烧结制备 3

1.5 本课题的研究内容和研究意义 3

1.5.1 研究意义 3

1.5.2 研究内容 3

第二章 实验方法与性能表征 4

2.1 实验原料 4

2.2 实验仪器 4

2.3 陶瓷样品的制备工艺 5

2.4 测试与表征方法 6

2.4.1 显气孔率和体积密度的测试 6

2.4.2 物相组成分析 6

2.4.3 显微结构分析 6

2.4.4 导热性能测试 6

2.4.5 抗弯强度的测试 7

第三章 实验内容与分析 9

3.1 不同含量的Y₂O₃-SiO₂-Al₂O₃助剂对各项性能的影响 9

3.1.1 烧结性能 9

3.1.2 物相分析 11

3.1.3 显微形貌 11

3.1.4 导热性能 12

3.1.5 抗弯强度 13

3.2 不同含量的Y₂O₃-SiO₂助剂对各项性能的影响 14

3.2.1 烧结性能 14

3.2.2 物相分析 16

3.2.3 显微形貌 16

3.2.4 导热性能 17

3.2.5 抗弯强度 18

3.3 本章小结 18

第四章 结论与展望 20

4.1 主要结论 20

4.2 展望 20

参考文献 22

致 谢 24

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