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| 摘要: |
| 高温低能高电流密度离子注入技术，已表明可以显著改善各种材料的摩擦学性能。本文综述了此领域中一些研究结果，并在奥氏体不锈钢和工具钢材料上对该技术与离子氮化和在相同条件下高能离子注入技术作了比较。显微结构分析及摩擦学性能评价表明，三种技术可以产生差不多相同的显微结构，但低能离子注入层由于具有较高的氮浓度和较深的扩散层而显示了较高的耐磨性。本文提出了一个物理模型来表示这种现象的机理。高电流密度是形成较深氮化层的主要原因，而离子能量具有次要作用，只要它能克服表面障碍，去除原有的氧化层，防止表面氧化，井在表面上建立起较高的氮浓度就可促进随后的快速扩散。对该技术的应用与限制也进行了论述。 |
| 关键词: 工具钢 离子氮化 奥氏体不锈钢 氮化层 扩散层 表面 显微结构分析 高电流密度 高温 去除 |
| DOI： |
| 分类号:TG174 TQ114.262 |
| 基金项目: |
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| Low Energy, High Current Density Ion Implantation of Materials at Elevated Temperatures for Tribological Applications |
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R. Wei
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| Abstract: |
| Low energy, high current density ion implantation at elevated temperatures has been shown to improve significantly the tribological properties of various materials. This paper summarizes the results published previously in this research area and presents some new results. Comparisons of this technique are made with ion nitriding and high energy ion implantation conducted under similar conditions (treatment temperature, treatment time and so on ) on austenitic stainless steel and tool steel materials. The microstructures analyses and tribological evaluations presented here show that all three techniques generate almost identical microstructures on each metal studied, but low energy ion implantation produces treated layers with higher nitrogen concentrations and deeper diffusion, leading to higher wear resistance. A physical model is proposed to explore the mechanisms for these advantageous phenomena. The analysis shows that a high culrent density is the primary mechanism responsible for the formation of deep nitrogen-containing layers. The ion energy is of secondary imPortance, as long as it is sufficiently high to overcome certain surface barrier potentials, to allow the removal of native oxide layers, to prevent surface oxidation and to allow the build-up of a high concentration of atomic nitrogen on the top of the treated surface to facilitate subsequent fast diffusion. Some applications and limitations of this technique are also addressed. It seems evident that low energy implantation (slightly higher than for ion nitriding, but much lower than for high energy ion implantation) at high current densities (much higher than those used in both ion nitriding and high energy implantation) generates superior nitrogen-containing layers on many materials, and hence the superior tribological performance compared to the other two techniques. |
| Key words: Low energy implantation, Ion nitriding, Steels, Elevated temperatures |
