"Study on Development of High Temperature Multipurpose-Furnace with High Energy and High Power Plasma Heat Sources"

为了开发一种新型的高温等离子体炉，并将其应用于材料的高温试验、新合金的生产和表面改性等多项技术中，本研究开发了气体隧道式等离子体射流高温等离子体炉，并对这种新型等离子体炉的性能进行了研究。利用这种高温等离子体炉在氮气气氛中进行了钛材料的低压表面氮化。结果表明：(1)在P=20kW时，该等离子体炉的热效率超过80%。在氮气气氛中，该等离子体炉的热效率超过80%。(2)对于20kW的Ar等离子体，当炉压低于40hPa时，其中心温度约为3000K，而在氮气等离子体中，中心温度高得多，达到3500K，且等离子体体积比Ar等离子体的CACE小得多。随着焊枪与衬底之间距离的减小，衬底表面温度升高。在1=100 mm时，TiN薄膜的维氏硬度为Hv=1500。(4)阐明了TiN薄膜的维氏硬度与衬底温度的关系。结果表明，当衬底温度大于1000K时，TiN薄膜的维氏硬度较高。

This study was carried out in order to develop a new type of high temperature plasma furnace and to apply of this plasma to various technologies, for example.high temperature test of materials, production of new alloys and surface modifications.In this study, the high temperature plasma furnace with gas tunnel type plasma jet has been developed and the performance of this new type plasma furnace was investigated.And, the surface nitridation of titanium materials was carried out at low pressure in nitrogen atmosphere by using this high temperature plasma furnace.The results obtained are as follows :(1) The thermal efficiency of this plasma furnace is more than 80% at P=20kW.In the case of nitrogen plasma, the efficiency becomes a little larger.(2) The temperature at center of the furnace is about 3000 K for argon plasma at 20 kW,when the pressure of the furnace is less than an 40 hPa.In the case of nitrogen plasma, much higher temperatureof 3500K was obtained and the the volume of plasma was smaller than the cace of argon plasma.(3) The TiN film in thickness of 10 mum was formed in the furnace. The surface temperature of the substrate was increased as the distance between torch and substrate was decreased. The Vickers hardness of TiN film was Hv=1500 at 1=100mm.(4) The relation between Vickers hardness of the TiN film and substrate temperature was clarified. It was proved that Vickers hardness of the TiN film was much higher when the substrate temperature was more than 1000 K.