MANUFACTURING OF AN OXYGEN PLSMA TRI-ARC FURNACE FOR OXIDE CERAMICS

1. 购买了三套氧等离子体火炬和动力单元，并制造了一个控制单元，该控制单元可以使火炬操作从传递模式瞬时过渡到非传递模式。为了初步的熔炼实验，我们制造了一个带有固定火炬的简易炉，通过这个实验，我们寻找合适的熔炼条件和制造最终炉所需要的数据。通过在预炉上对氧化锆合金的熔化实验，得到了以下结果：(1)氧化钇掺杂的氧化锆在氧等离子弧下可以不还原熔化。(2)虽然铈掺杂的氧化锆在凝固过程中产生了枝晶结构，但这可以通过低于熔化温度的均质加热来消除。(3)对于10mm以上的试样，由于氧等离子体电弧较细，加热不均匀。在此基础上，研制了具有上下运动的旋转炉膛的加热炉。

1. Three sets of oxygen plasma torches and power units were purchased and a control unit which enables instantaneous transition from a transfer mode to a nontrnasfer mode of a torch operation were manufactured.2. A simple furnace with fixed torches were manufactured for preliminary melting experiments through which suitable conditions for melting were sought and data necessary for manufacturing a final furnace.3. Through the melting experiments of zirconia alloys using the preliminary furnace, the following results were obtained : (1) Yttria doped zirconia could be melted without reduction under the oxygen plasma arc. (2) Although ceria doped zirconia resulted in dendrite structure through the solidification, this could be removed by homogenizing heating just below the melting temperature. (3) Because of the thin arc of the oxygen plasma, heating of a spcimen above 10mm size could not be heated uniformly.4. Based on these data, a furnace with a rotating hearth with up-down motion was manufactured.