纯氮离子渗氮工艺及机理研究

Research on Processes and Mechanism of Ion Nitriding in Pure Nitrogen

采用高电压低气压、闭炉保温的渗氮工艺对合金钢在纯氮气氛下进行离子渗氮 ,测定了渗氮层的硬度梯度、渗层深度和相组成。在相同的渗氮时间里 ,纯氮离子渗氮获得了比以氨气作为渗氮气源进行离子渗氮更好的效果。而且克服了氨气渗氮容易产生环境污染的缺点。通过对纯氮渗氮不同工艺的对比试验 ,发现只有在足够高的电压下才有明显的渗氮效果。分析了离子渗氮过程中阴极位降区离子的行为 ,也对渗氮电压如何影响活性氮原子的产生进行了定量的计算 ,探讨了纯氮离子渗氮的机理。

Alloy steel was nitrided under the atmosphere of pure nitrogen,using the ion nitriding process by high voltage,low air pressure and soaking in closed furnace.The hardness gradient,depth and phases of nitrided layers were measured.The result shows that under the same nitriding time,better experiment effects were achieved by using pure nitrogen than that by NH 3,and the former process overcomes the disadvantage of NH 3 which is inclined to produce environmental pollutions.After the comparison of various processes of pure nitrogen ion nitriding,it is found that obvious nitriding effects can be achieved only on the condition of sufficiently high voltage.The behavior of molecule or ion around cathode zone on the process of ion nitriding was analyzed,quantitative analysis of nitriding voltages effect on the production of active nitrogen atoms was made,and the mechanism of pure nitrogen ion nitriding was discussed.