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

为了研制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、新型合金的生产和表面改性等各种技术中，本研究开发了一种具有气体隧道式等离子体射流的高温等离子体炉，并对这种新型等离子体炉的性能进行了研究。利用该高温等离子体炉对钛材料进行了低压氮气氛下的表面氮化处理，结果表明：（1）在P= 20 kW时，该等离子体炉的热效率大于80%，在氮等离子体的情况下，热效率略有提高。(2)当炉内压强小于40 hPa时，20 kW氩等离子体的炉心温度约为3000 K，而氮等离子体的炉心温度远高于氩等离子体，可达3500 K，且等离子体体积小于氩等离子体。(3)在炉中形成厚度为10 μ m的TiN膜。基底表面温度随着喷枪与基底之间距离的减小而升高。TiN膜的维氏硬度在1= 100 mm处为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，当衬底温度高于1000 K时，TiN薄膜的维氏硬度明显提高。

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.