单端灯丝放电等离子体空间分布及离子注入均匀性研究-材料加工工程专业论文.docxVIP

哈尔滨工业大学工学硕士学位论文 哈尔滨工业大学工学硕士学位论文 - - II - Abstract Filament discharge plasma source has gained more interests due to easily obtaining high-density plasma at low gas pressure. However, the non-uniformity of the plasma density distribution has been restricting the further development of filament discharge plasma in the process of modern industrialization. In this thesis, the uniformity of single filament discharge plasma was systematically studied. The plasma characteristics of filament discharge in different anode shapes were diagnosed by Langmuir probe. The uniformity of ion density in the axial and radial direction was monitored and the influence of the pressure and anode current on plasma behavior has been discussed. Nitrogen plasma ion implantation into stainless steel substrate was performed using this technique. Tribological and electrochemical properties of treated surface were evaluated, respectively. The effects of the pressure, anode current and pulse bias voltage on the uniformity as for surface properties were focused on. The results show that the plasma densities induced by filament discharge are all above 1×1010 cm-3, and anode configuration has an important effect on the uniformity of plasma density distribution. When vacuum chamber acts as anode, the ion density is somewhat low and the uniformity of ion density along axial distribution is poor (non-uniformity is up to 65%). Flat-panel anode can increase ion density and the uniformity of ion density along axial distribution, but the uniformity of ion density along radial distribution is deteriorated. Arc-shaped anode can improve the ion density and uniformity of ion density along axial distribution, but also overcome the shortcoming of flat-panel anode. Thus available large area uniform and high-density plasma is obtained, and the non-uniformity of plasma density along axial and radial is 40% and 10%, respectively. The wear resistance of treated stainless steel samples has been greatly improved. But th