In the paper, a novel metal surface nitriding method is presented by using an atmospheric pressure non-thermal transferred arc plasma technique. In the N2/H2 plasma nitriding process, the surface of stainless-steel is treated by the arc root, which shows an irregular movement in a circle-like zone with about 5 mm diameter observed by high speed camera. The discharge has characteristics of high voltage and low current, and the gas temperature of the arc column plasma is only about 2900 K determined by the diatomic molecule N2+(B2Σu+→X2Σg+) fitting method. It is found that the NH radical production in plasma plays an important role in the nitriding process. The thickness of nitrided layer can reach 60 μm after processing of 120 min under the optimal experimental conditions. The surface hardness of stainless-steel increased from 220 to about 1200 HV0.1 (Vickers hardness under the force of 0.1 kg) after plasma treatment. The treating saturation time for stainless-steel surface hardness reaching to 1200 HV0.1 is around 9 min.

中文翻译：

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不锈钢在常压下的 N2/H2 非热转移电弧等离子氮化处理

本文提出了一种采用常压非热转移电弧等离子体技术的新型金属表面氮化方法。在N2/H2等离子渗氮工艺中，不锈钢表面经过弧根处理，高速相机观察到的直径约5mm的圆形区域呈不规则运动。放电具有高电压、低电流的特点，通过双原子分子N2+(B2Σu+→X2Σg+)拟合方法确定的弧柱等离子体气体温度仅为2900 K左右。发现等离子体中NH自由基的产生在渗氮过程中起着重要作用。在最佳实验条件下，经过120 min的处理，氮化层厚度可达60 μm。不锈钢的表面硬度从220 HV0提高到1200 HV0左右。1（在0.1公斤力下的维氏硬度）经过等离子处理。不锈钢表面硬度达到 1200 HV0.1 的处理饱和时间约为 9 分钟。