用于燃煤磁流体发电通道的Sialon绝缘材料的研究

Study on Sialon Insulation Materials for Channel in Coal—Fired MHD Generator

本文研究了Sialon陶瓷的组成和工艺条件;制备了用作燃煤磁流体发电通道绝缘材料的Sialon试样;测定了Sialon陶瓷的电绝缘性、抗热震性、抗溶渣腐蚀性、电场强度、导热性和热膨胀系数等项性能。结果表明,Sialon陶瓷有良好的抗热震性、抗熔渣腐蚀性、电绝缘性、电场强度和其它物理—力学性能。Sialon陶瓷的良好性能已在静态试验和动态试验(累计试验时间分别多为85、202和85小时)中得到证实。动态试验先后于1988、1989和1990年在中国科学院电工研究所进行。静态腐蚀和动态试验结果分析表明,钾和熔渣中其它有害物质并扩散到材料内部而只聚集在试样表面。熔渣和试样之间的反应很微弱,在壁面温度很低时这种作用甚至可以忽略。电弧和熔渣粒子冲刷也会造成试样损伤。研究结果表明,Sialon陶瓷是一种很有希望的燃煤磁流体发电通道绝缘材料。

The composition and processing condition of sialon were investigated. Sialon blocks for channel insulation in coal-fired MHD generation were fabricated. Measurements on insulation resistivity, thermal shock resistance, slag corrosion resistance, electrical field intensity, thermal conductivity and thermal expansion coefficient etc for sialon blocks were conducted. The results indicated that sialon ceramics has very good thermal shock resistance,slag corrosion resistance, insulation resistivity, electrical field intensity and other physical-mechanical properties. Excellent performance of sialon blocks in static tests as well as in dynamic tests (accumulated test time be 85,202 and 256 hours respectively) have been demonstrated on the channel coal-fired MHD generator. The dynamic tests were done in 1988,1989 and 1990 by the Electrical Engineering Institute of Chinese Academy of Sciences. Results of both static corrosion tests and dynamic tests have shown that the k and other harmful materials in the slag did not diffuse into the samples and only accumulated on the surface of the samples. No serious reaction between slag and samples has been observed,and the effects could even be neglected where the surface temperature was low. Arc and slag particles scoring also caused the damage of samples. The results indicated that sialon is a promising insulation materials for channel in coal-fired MHD generation.