Research on a functional inverter discharge plasma and a deposition of low frictional thin films for metal mechanical parts

本文介绍了一种用旋转泵获得中等本底气压（10^1 ~ 10^3 Pa）的直流辉光放电系统的逆变器直接驱动技术。由于所开发的系统产生的等离子体具有与直流等离子体基本上相似的性质，我们可以利用简单的放电电极，如平行板，这将被扩展为大面积处理，在一个低成本。另外，由逆变电路产生的双极性脉冲驱动的等离子体具有电荷抵消功能，有利于隔离表面处理。本研究获得了以下结果：1.在一对平行板电极之间产生了气压为100 Pa的Ar等离子体。等离子体峰值密度为1 ×10 ~（-6）<10>cm ~ 2<-1>，峰值温度为2 × 10 ~（-6）eV，可用于实际的表面处理和薄膜沉积。2.采用异步高压交变脉冲方式，在中等以上气压范围内改善了溅射薄膜的附着性能。在100 ~ 600 Pa（甲烷）压力下，以1.5μm/h的沉积速率在SUS 304和Si（100）衬底上沉积了DLC膜。通过膜厚测量、显微维氏硬度测试、原子力显微镜、傅立叶变换红外光谱和拉曼散射光谱等手段对DLC膜的基本特性进行了评价。作为滑动试验的实际结果，我们还观察到涂覆有DLC膜的金属部件之间的动摩擦系数的降低。

An inverter-direct-driving technique has been introduced to a dc glow discharge system in a middle background pressure resion (10^1〜10^3 Pa) obtained with rotary pumps. Because the plasma produced with the developed system has the similar properties as those of dc plasmas basically, we can utilize simple discharge electrodes such as parallel plates that would be extended for large area processing in a low cost. In addition, the plasma driven by the bipolar pulses from the inverter circuit has a charge-up cancellation function that is advantageous to isolated surface treatments.We have obtained the following results from this research.1.We produced an Ar plasma at a pressure of 100 Pa between a pair of parallel-plate electrodes. The peak plasma density and temperature were 1〜6×10^<10> cm^<-1> and 2〜6 eV, which indicates that this discharge can be applicable to practical surface treatment and film deposition.2.Using an asynchronous high-voltage alternating pulsing mode, we have improved the adhesion property of a sputtering thin film under the above middle pressure region.Next, a diamond-like carbon (DLC) film deposition experiment has been performed. The DLC films have deposited on SUS304 and Si (100) substrates under a pressure of 100〜600Pa (methane) at a deposition rate of 1.5μm/h. The basic characteristics of the DLC films have been estimated with film thickness measurement, micro Vickers hardness test, AFM, FTIR, and Raman Scattering Spectroscopy. As a practical result of a sliding test, we have also observed the decrease of the kinetic friction coefficient between metal parts coated with the DLC films.