High-rate Synthesis of Hybrid Coating Films by Plasma-Spraying Enhanced Chemical

本研究利用电弧辉光混合等离子体制备纳米结构的Ti-DLC薄膜。一种沉积装置，包括直流等离子体炬、衬底保持器和真空室。在火炬出口处安装一个直径为10 mm的小孔，可以在火炬和燃烧室之间产生压差。腔室由5，000 L/min的干式泵抽真空。即使火炬中的压力为1 atm，孔板和大型真空泵也可以将腔室中的压力保持在20-100 Pa。该喷枪采用钛空心阴极，通过电弧放电将钛蒸发，然后用等离子体射流喷涂到基体上。腔室中的压力足够低以产生缓慢放电。采用13.56MHz的射频电源与基片保持器连接，产生辉光放电等离子体，并在基片上施加负偏压，以C_2H_2和CH_4为反应气体，制备了Ti-DLC薄膜。典型的沉积条件为 ...更多信息 如下所示：直流电压和电流：13-15 V，30-150 A，氩气流量0.5-1.6 L/min，甲烷和乙炔流量0.02-1 L/min，射频功率100- 150 W，负偏压100- 400 V。SEM观察和EDAX分析结果表明，该膜不仅包括纳米尺寸（即1 - 50 nm）的Ti颗粒，而且还包括碳基体中的大液滴。通过拉曼光谱分析确定了碳基体为类金刚石。采用旋流发生器减少液滴，发现当C_2H_2与Ar一起在旋流中进入等离子体炬时，大部分液滴被消除。随着薄膜中Ti含量从0降低到30vol%，沉积薄膜的硬度从13增加到30 GPa。在1h的沉积时间内，薄膜的厚度约为5 μ m，与不锈钢球的摩擦系数为0.3。钛纳米颗粒的分散似乎降低了残余应力。这些结果表明，电弧辉光混合等离子体化学气相沉积法可以在高的生长速率下制备厚的Ti-DLC膜。少

This study presents fabrication of nano-structured Ti-DLC films using are-glow hybrid plasma. A deposition apparatus consists of a DC plasma torch, a substrate holder and a vacuum chamber. An orifice of 10mm diameter mounted at the exit of the torch can generate pressure difference between the torch and the chamber. The chamber is evacuated by a dry pump of 5,000 L/min. The orifice and the large-scale vacuum pump enable to keep the pressure in chamber at 20-100 Pa, even if the pressure in the torch is 1 atm. The torch employs hollow cathode made of Ti, the Ti is evaporated by the arc discharge, and then sprayed onto the substrate with a plasma jet. The pressure in chamber is low enough to generate a slow discharge. The 13.56MHz RF power supply is connected to the substrate holder to generate a glow discharge plasma as well as to add a negative bias on the substrate.Deposition of Ti-DLC films were performed using C_2H_2 and CH_4 as the reactant gases. Typical deposition condition was as … More follows : DC voltage and current : 13-15 V,30-150 A ; Ar for torch : 0.5-1.6 L/min ; CH_4 and C_2H_2 flow rate : 0.02-1 L/min ; RF power : 100-150W : negative biasing voltage : 100-400V. SEM observation and EDAX analysis results suggest that the film includes not only nano-size (I.e. l-50nm) Ti particles but also large droplets in carbon matrix. The carbon matrix was assured as DLC according to Raman spectrascopy. The swirl now generator was adopted to reduce the droplets, it was found that most of droplets were eliminated when C_2H_2, was supplied into the plasma torch together with Ar in the swirl flow. The hardness of the deposited film increased from 13 to 30GPa with decreasing the Ti content in the film from 0 to 30 vol.%. The thickness of the film was approximately 5 um in l h deposition and the friction coefficient was 0.3 against stainless steel ball. The residual stress seems to be decreased by the dispersed Ti nano-particle. These results lead to the conclusion that thick Ti-DLC film can be fabricated at high growth rate by the arc-glow hybrid plasma CVD. Less