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1、 密级:内部硅粉粒度对反应烧结氮化硅陶瓷显硅粉粒度对反应烧结氮化硅陶瓷显微结构的影响微结构的影响InfluenceInfluence ofof SiliconSilicon powderpowder sizesize onon microstructuremicrostructure ofof Reaction-bondedReaction-bonded SiliconSilicon NitrideNitride CeramicsCeramics 学 院:材料科学与工程学院专 业 班 级:无机非金属材料工程 1002 班学 号:学 生 姓 名: 指 导 教 师:(副教授) 2014 年 6 月
2、I摘 要氮化硅陶瓷是一种满足耐热、透波、承载,综合性能十分理想的功能陶瓷材料,机械强度高、热稳定性好、密度低、比重小、化学性能稳定,氮化硅雷达天线罩可以在高马赫数飞行器上使用,氮化硅陶瓷透波性能好,介电常数低,比重小(反应烧结为 2.22.6gcm3,常压烧结约为 3.0gcm3),易加工至精密尺寸,其介电性能随温度变化小,抗热震和抗腐蚀性也好,这些性能都是作为高速飞行器雷达天线罩所必备的。本文主要原料为硅粉(Si)、氮气(N2),PVA 溶液作为粘结剂,采用反应烧结的方法,以 Si 粉为原料, 通过氮化反应生成 Si3N4。由于陶瓷材料的性能取决于粉料的组分设计、成型及烧结工艺等制备过程,起
3、始粉料颗粒的大小对陶瓷材料的烧结特性和制品性能起着尤为重要的作用,因此此次实验主要研究硅粉粒度对反应烧结氮化硅陶瓷显微结构的影响,经过计算、配料、成型、烧结和腐蚀,对样品进行扫描,并对扫描结果进行观察、对比和分析,从而得出不同粉料粒度所得样品的颗粒大小、气孔率及致密度等的差别。本次实验得出以下结论:不同粒度硅粉所制得的氮化硅陶瓷中,800 目时硬度最好,其次为500 目、1000 目、1250 目;1250 目时耐腐蚀性能最好,500 目时最差。关键词:氮化硅陶瓷;硅粉粒度;关键词:氮化硅陶瓷;硅粉粒度;烧结烧结;腐蚀;腐蚀IIAbstractSilicon nitride ceramics
4、is a very good Functional ceramic materials that can meet heat wave transparent, bearing, it has high mechanical strength, good thermal stability, low density, specific gravity, chemical stability. Silicon nitride Radar natural cover can be used on the aircraft at high Mach numbers, silicon nitride
5、ceramics through waves of good performance, low dielectric constant, The proportion of small (reaction sintering of 2.2-2.6g/cm3, no pressure sintering about 3.0g/cm3), easy processing to precision dimensions, and its dielectric properties with temperature change is small, Thermal shock and corrosio
6、n resistance is good, these properties are used as high-speed aircraft natural cover are essential.This is the main raw material silicon powder (Si), nitrogen (N2), using PVA as a binder ,Using reaction sintering method, based on the reaction sintering of Si3N4 Si as raw materials, generated Si3N4 b
7、y Nitriding reaction. Since the quality of ceramic materials depends upon the performance of the process of preparation of powder component design , molding and sintering process, etc. ,the particle size of the starting powder and the sintering characteristics of the material properties of the ceram
8、ic article plays a particularly important role, and therefore the main purpose of this paper is researching the influence of Silicon powder size on microstructure of Reaction-bonded Silicon Nitride Ceramics. After calculation , ingredients, molding, sintering and etching , the sample is scanned and
9、observed ,and then compare and analyze the scan results to summary the differences in particle size results obtained samples of different powder particle size , porosity and density , etc. The experiment drew the following conclusions: In the different size of silicon powder, the best hardness is 80
10、0 mesh, and followed by 500 mesh, 1000mesh, 1250 mesh; For the corrosion resistance, 1250 mesh is the best one and 500 mesh is the worst.Keywords: Silicon nitride ceramic; Silicon powder size; Sintering; CorrosionIII目录摘 要.I Abstract.II 第 1 章 前 言 .1 1.1 氮化硅陶瓷 .1 1.1.1 简介 .1 1.1.2 基本性能 .1 1.1.3 应用 .2 1.1.4 成型方法 .3 1.1.5 烧结 .5 1.2 反应烧结氮化硅陶瓷.8 1.2.1 烧结机理 .8 1.2.2 中外研究发展近况.9 1.3 课题研究内容及目的.11 第 2 章 实验 .12 2.1 实验原料及制备过程.12 2.1.1 原料 .12 2.1.2 原料制备 .12 2.1.3 称量及混料 .12 2.1.4 陈腐 .