95氧化铝陶瓷直流击穿强度影响因素的研究

发布时间：2017-12-27 03:15

本文关键词：95氧化铝陶瓷直流击穿强度影响因素的研究　出处：《华南理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着我国西电东送以及高铁网络的跨越式发展,超高压真空管壳的需求量大幅提升,但是我国真空管壳的性能与国外的先进水平差距较大,主要体现在两方面:一是直流击穿强度较低,国内先进水平达到32.9kV/mm左右,而国外先进水平可达45kV/mm以上;二是烧成温度偏高,国内真空管壳生产主要是在空气气氛下烧成,烧成温度一般在1680℃,能耗较高,国外先进的企业已经开始尝试结合配方的创新,并采用特种烧结方式,烧成温度可降低150℃左右。上述两个原因导致了我国电真空管壳使用量的30%以上需要进口,其中超高压管壳全部依赖进口。超高压真空管壳是一种95氧化铝陶瓷材料,为了提高超高压真空管壳的直流击强度,降低其烧结温度,本文分两部分进行实验研究。第一部分是研究液相烧结助剂、烧成温度和氧化铝种类对95氧化铝陶瓷结构和性能的影响,通过正交实验分析法得出液相烧结助剂的最优水平为CaCO3+SiO2。为了进一步提高95氧化铝陶瓷的直流击穿强度,本文第二部分实验以CaCO3+SiO2作为液相烧结助剂,通过正交实验的方法研究了固相烧结助剂掺杂对95氧化铝陶瓷结构和性能的影响,结果发现以工业Al2O3为原料,掺杂质量分数分别为4.90%,0.77%,0.45%,0.30%和0.75%的SiO2,CaCO3,MgO,ZrO2和CeO2,并在1630℃下烧成出来的95氧化铝陶瓷的直流击穿强度达到57.6kV/mm,高于国外先进水平。通过对实验结果分析发现晶粒粒径(包括晶粒平均粒径和大晶粒粒径)决定陶瓷的击穿方式,体积密度、介电损耗和击穿方式共同影响直流击穿强度的大小。击穿方式仅为热击穿的陶瓷样品击穿强度较大。为了形成热击穿,晶粒平均粒径和大晶粒粒径均不能太大。为了提高击穿方式为热击穿的陶瓷的直流击穿强度,在其体积密度达到一定时,应优先降低其介电损耗。
[Abstract]:Along with our country from west to East and leap type development of high-speed rail network, demand for ultra high vacuum tubes increased significantly, but the performance of China and the international advanced level of vacuum tubes of the larger gap, mainly reflected in two aspects: one is the DC breakdown strength is low, the domestic advanced level and reach about 32.9kV/mm. The advanced level is up to 45kV/mm; two burning temperature is high, the domestic production of vacuum tube shell is sintered in air atmosphere, sintering temperature at 1680 DEG C, higher energy consumption, advanced foreign enterprises have begun to try to combine innovation with the party, and the special sintering, the sintering temperature can be reduced by 150 deg. The above two reasons lead to the import of more than 30% of the use of electric vacuum tube and shell in China, of which the ultra high pressure pipe shell all depends on the import. The ultra-high pressure vacuum shell is a 95 alumina ceramic material. In order to improve the DC impact strength and reduce the sintering temperature of the ultra-high pressure vacuum shell, this paper is divided into two parts for experimental research. The first part is the study of liquid phase sintering additives, sintering temperature and the effect of alumina species on the structure and properties of 95 alumina ceramics, through the analysis of orthogonal test method of optimal level of liquid phase sintering additives for CaCO3+SiO2. In order to further improve the DC breakdown strength of 95 alumina ceramics, the second part of this experiment using CaCO3+SiO2 as a liquid phase sintering aid, through the method of orthogonal experiment on the effect of solid phase sintering aids doped on structure and properties of 95 alumina ceramics, found in industrial Al2O3 as raw materials. The doping concentration was 4.90%, respectively, 0.77%, 0.45%, SiO2 0.30% and 0.75%, CaCO3, MgO, ZrO2 and CeO2, DC breakdown strength and firing out at 1630 DEG C of 95 alumina ceramics reached 57.6kV/mm, higher than the international advanced level. Through the analysis of the experimental results, it is found that grain size (including the average grain size and large grain size) determines the way of ceramic breakdown, and the volume density, dielectric loss and breakdown mode affect the DC breakdown strength. The breakdown strength of ceramic samples with a breakdown only for thermal breakdown is larger. In order to form thermal breakdown, the average grain size and grain size of the grain can not be too large. In order to improve the DC breakdown strength of the ceramic with the breakdown mode for thermal breakdown, the dielectric loss should be reduced first when the volume density reaches a certain extent.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ174.1

【相似文献】