【作者】 郭学平；

【导师】 高阳；

【作者基本信息】 大连海事大学 ， 载运工具运用工程， 2005， 硕士

【摘要】 氮化工艺自上个世纪产生以来,至今已有近百年的历史,已经取得了相当大的进展而且也获得了广泛的工业应用。尽管氮化技术已经历了长时间的发展,但仍存在许多不足,最显著的一点是氮化时间过长,通常都需要几小时甚至几十小时来完成氮化过程。如何通过新的工艺来降低氮化成本、缩短氮化时间一直以来都是广大渗氮研究工作者所关心的课题。 热等离子束作为热力学局部平衡等离子体,与低温非平衡等离子体相比,其离子、电子的密度高,不仅电子交换能量,部分重离子也参与能量传递,远比非平衡辉光等离子、电晕放电时高得多。热等离子束因其具有较高的能量及一定的粒子浓度,应该可以作为一种等离子体源对材料进行表面氮化,并且有可能大大缩短工艺时间、节约工艺成本并简化操作。 基于以上原因,我们开发出利用热离子束照射进行氮化实验的装置,并利用该装置对纯铁的氮化行为进行了相关研究,主要研究成果如下:1.渗氮炉可以满足实验要求,利用N₂-H₂气体产生的热等离子束照射纯铁进行氮 化实验,渗氮速度比传统辉光离子氮化大大提高,将热等离子束照射进行氮化 这一理论设想从转变为实际,验证了等离子束照射渗氮的可行性。2.温度参数对氮化过程影响很大。在照射温度较低的情况下,试样几乎不能形成 氮化层,随着照射温度的升高,试样获得不同组织的渗层。3.试样表面硬度与渗层中含氮量表现出一定的对应关系。4.在照射温度比较高的情况下,试样渗层获得了和传统离子氮化明显不同的组 织,试样表层与基体之间形成了过渡层,并且过渡层与表层及基体之间形成不 同程度裂缝状。更多还原

【Abstract】 Nitriding technology, achieved a great development in the last century, has become a very important technology in surface modification. This technology, however, still has some shortcomings of which the remarkable one is it costs a relative long time to accomplish nitriding process. Many researchers are contributing to find a new method to reduce nitriding time and enhance nitriding efficiency.Thermal plasma, unlike low temperature non-equilibrium plasma, is in the condition of local-thermal-equilibrium （LTE）. Ions and almost have same temperature with electrons of which up to 20,000K. The energy of ions is very high, which will benefit accelerating the reaction between N-ions and substrate and increasing nitriding speed.Because of the above reasons, we developed a new device which applied N₂-H₂ thermal plasma jet to nitriding on pure iron. Following results can be drawn:1. Compared with traditional nitriding process, thermal plasma nitriding had a much more increased reaction speed, which proved the feasibility of this technology.2. Temperature had a notable influence on formation of the nitrided layer. The nitrided layer shows different characters under different dispose temperature.3. Surface hardness of the nitrided sample and the N-content in nitrided layer show a certain relationship4. Compared with ion-bombardment nitriding method, different layers of the samples irradiated by thermal plasma can be obtained under a relative high processing temperature. A transform layer was formed between the compound layer and the ferrite iron.更多还原