【作者】 张效华；

【导师】 李晓池；

【作者基本信息】 西安科技大学 ， 矿物加工工程， 2006， 硕士

【摘要】 传统工艺条件下生产的碳化硅电热元件存在着电阻离散性大、成品率低、强度低、使用温度低、致密度差等问题。这些难题长期以来制约着碳化硅电热元件行业的技术进步、产业升级、节能降耗、经济效益提高和出口创汇。因此摸索碳化硅电热元件的新型制备工艺与探讨其结晶性能，对于改善其使用性能、提高成品率、使用温度以及发展新型碳化硅电热元件都是非常必要的。近年来由于环保的需要，传统煤烧、油烧窑炉、逐渐向气烧和电烧转变，加之建筑材料、耐火材料、电子陶瓷产品的更新换代，大部分电子陶瓷产品、高级建筑材料、高级耐火材料都开始使用电热窑炉烧成，随着我国工业窑炉和高温技术的发展，对碳化硅电热元件的使用温度和使用寿命也提出了更高要求。本文的主要研究内容包括： (1) 通过优化素烧和烧成窑中的保温料配方，改善保温料的导热和保温性能，扩大并均匀温场，以提高成品率、扩大产量。 (2) 用现代测温技术、控温技术，严格控制烧成曲线，解决素坯温度梯度大造成的素烧变形问题，以达到提高成品率的目的。 (3) 利用单热源和双热源碳化硅合成炉，进行碳化硅电热元件的烧成试验。解决碳化硅电热元件热端烧成中窑内温差大、温度不能精确控制，制品过烧和生烧造成的单体结晶性能差异大、电阻离散性大、力学性能差、成品率低的问题。 (4) 使用X-射线粉末衍射仪对制品的物相进行分析，使用电子扫描显微镜对制品表面形貌、孔道结构与分布、晶体结构进行分析。 通过对制备工艺的研究和制品性能的测试，找出最佳的素烧温度和最佳素烧填充料，并对比了单热源烧成和多热源烧成的温度场的特点，找出了烧成的最佳温度区域。通过对制品的物相分析和结构表征，进一步探讨烧成机理：碳化硅电热元件的再结晶反应，就是在高温还原气氛中，棒体中次生碳化硅晶粒生成、长大、原碳化硅长大，而后相互接触成为紧密堆积的聚集体的过程。探讨了碳化硅电热元件高温失效的主要原因，更多还原

【Abstract】 Silicon carbide electro-heating element under conventional production technology have some disadvantages of big resistance discreteness, the low rate of finished products, low intensity, low usage temperature and bad density. These problems restrict the technology development and upgrade of silicon carbide electro-heating element industry. So those are necessary to grope new preparation technology and probe into crystal property for improving application properties and increasing the rate of finished products and developing new style electro-heating element. Currently, because of environment’s problem, the furnace using coal and oil gradually converts using gas and electricity. Architectural material, fire-resistant material, electronic ceramics begin to renovate, the most of these products need to be sintered in the electro-heating furnace. With the development of Chinese industry furnace and high temperature technology, the usage temperature and life of silicon carbide electro-heating element need to be heightened. The article mainly researching content including:(1) By optimizing the heat preservation materials compounding of the biscuit firing and sintering furnace, the heat conduction and preservation characteristics are improved. Temperature field is enlarged and uniformed for increasing the rate of finished products and increasing yield.(2)Applying modern measuring and controlling temperature technology, sintering curve is strictly controlled. The biscuit deformation brought by big temperature gradient is solved.(3) Applying single thermal source and double thermal sources SiC synthesizing technology, Silicon carbide electro-heating element sintering are experimented. Because there are big temperature difference in furnace and temperature can’t be controlled accurately, the heating rod are sintered excessively or greenly, which brings different crystal properties and big resistance discreteness and low intensity, these problems are solved.更多还原