Rapid Nitriding of Aluminum Using Nitrogen Glow Plasma

采用氮射频辉光等离子体对铝进行了快速氮化处理。结果总结如下。以铝粉为原料，在1000℃下快速氮化10min，转化率达94%。射频源的最佳极板功率为1.85kW。直径1微米的氮化铝纤维。被密集地包裹在氮化样品中。这种快速低温氮化尚未见报道，可能是由活性氮N、N^+和N_2^+引起的。此外，其他形状的铝也实现了快速低温氮化；颗粒（phi6.2mm*5.5mm），板材（0.5*10.0*10.0mm），立方体（l0.0*l0.0*4.0mm），直径2mm的颗粒。采用Ar或H_2等离子体进行预处理。在Ar或Ar/H_2等离子体中没有发现这种效应。而采用H_2等离子体对铝板进行预处理，铝板的转化率提高到97%。并对氮化过程进行了中断反应的研究。当使用由雾化粉末制备的球团时，可以清楚地观察到反应过程。在这种情况下，氮发光等离子体在铝体表面进行氮化。边界处的铝被反应热蒸发，与活性氮反应，在表面沉积A1N枝晶。内部的铝移动到边界，在样品底部形成一个洞穴。

The bulk of aluminum was rapidly nitrided using nitrogen r.f. glow plasma. The results were summarized below.A pellet formed from aluminum powder was rapidly nitrided at 1000ﾟC for 10min with a conversion of 94%. The optimum plate power of r.f. source was 1.85kW.Aluminum nitride fibers with 1mum in dia. were densely packed in the nitrided sample. This nitriding may be caused by activated nitrogen species N, N^+ and N_2^+, because such rapid and low-temperature nitriding has not been reported. Furthermore, the rapid and low-temperature nitridings were also achieved in the aluminums with other shapes ; grain(phi6.2mm*5.5mm), plate(0.5*10.0*10.0mm, cube(l0.0*l0.0*4.0mm) and grains with 2mm in dia.Pretreatment was done by Ar or H_2 plasma. The effect was not recognized in Ar or Ar/H_2 plasma. However, when H_2 plasma was used for the pretreatment of Al plate, the conversion of Al plate was increased to 97%.Furthermore, the nitriding process was studied by the interruption of the reaction. When the pellets prepared from atomized powder were used, the reaction process was clearly observed. In this case, the nitriding by the nitrogen glow plasma proceeds on the surface of the aluminum bulk. The aluminum at the boundary is evaporated by the reaction heat to react with the activated nitrogen, depositing A1N dendrites on the surface. The aluminum inside moves to the boundary to make a cave at the bottom of the sample.