【作者】 徐祥久；

【导师】 田修波；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2008， 硕士

【摘要】 灯丝放电等离子体源具有设备结构简单、可在低气压上产生高密度的等离子体等优点,在真空等离子体工艺中有着广泛的应用。然而等离子体分布的不均匀性一直是制约灯丝放电等离子体继续向前发展的一个重要因素,在现代产业化和工业化的过程中,往往又要求等离子体源能够产生高密度、大面积均匀性好的等离子体,以实现降低产品成本和批量生产的目标。本文主要对单端灯丝放电等离子体均匀性进行了系统的研究。采用Langmuir探针对不同阳极形式条件下,灯丝放电产生的等离子体特性进行了诊断,研究了离子密度在轴向和径向分布的均匀性,分析了气压、阳极电流以及挡板对离子密度变化规律的影响。并采用该等离子体源在不锈钢表面进行氮离子注入,对注入后不锈钢表面的摩擦学性能和电化学腐蚀性能进行了评价,分别讨论了工作气压、阳极电流和注入电压对离子注入改性层性能均匀性的影响。研究结果表明,灯丝放电产生的等离子体密度均在1×10¹⁰cm^-3以上,阳极形式对离子密度分布的均匀性有很大的影响。真空室为阳极时,等离子体密度较低,离子密度分布的轴向不均匀度可达65%以上;使用平板阳极可以提高离子密度及其轴向分布的均匀性,但却使离子密度径向分布的均匀性变差;圆弧状阳极既可以提高离子密度和密度轴向分布的均匀性,同时又克服了使用平板阳极时离子密度径向分布的不均匀性,可以获得大面积高密度均匀的等离子体,离子密度分布的轴向和径向不均匀度分别在40%和10%以下。利用灯丝放电等离子体源对不锈钢表面进行氮等离子体浸没离子注入,研究表明,处理后的试样,其表面耐磨性得到了很大的提高,但由于离子的轰击导致表面缺陷的增多,氮离子注入后,不锈钢表面的耐腐蚀性能变差。随着工作气压的升高,轴向和径向位置的试样的耐磨、耐蚀性能均匀性逐渐变差。增大阳极电流会使试样的耐磨、耐蚀性能的均匀性变好,而注入电压对不同位的试样耐磨、耐蚀性能的均匀性的影响不大。更多还原

【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 the corrosion resistance decreases because of defects caused by ion bombardment in the process of nitrogen ion implantation.With the increase of pressure, the uniformity of tribological properties of the modified layers and electrochemical corrosion properties of samples at the different position gradually decreases. With the increase of anode current, the uniformity of tribological properties of the modified layers and electrochemical corrosion properties of samples at the different position would increase. But implantation voltage does little effect on the uniformity of tribological properties of the modified layers and electrochemical corrosion properties of samples at the different position.更多还原