Effect of relative humidity on the tribological properties of hydrogenated diamond-like carbon films in a nitrogen environment
Effect of relative humidity on the tribological properties of hydrogenated diamond-like carbon films in a nitrogen environment
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DOI：
10.1088/0022-3727/38/1/011
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发表时间：
2005-01
期刊：
影响因子：
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通讯作者：
Hongxuan Li;T. Xu;Chengbing Wang;Jianmin Chen;Hui-di Zhou;Huiwen Liu
中科院分区：
文献类型：
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作者：
Hongxuan Li;T. Xu;Chengbing Wang;Jianmin Chen;Hui-di Zhou;Huiwen Liu
采用等离子体增强化学气相沉积（PECVD）技术，以CH 4 + Ar为原料，在Si（100）基片上沉积了氢化类金刚石（DLC）薄膜。在氮气环境中，以Si 3 N4球为摩擦副，采用球-盘摩擦磨损试验机测试了不同相对湿度（5%~ 100%）下薄膜的摩擦磨损性能。用扫描电子显微镜对薄膜和氮化硅球的摩擦表面进行了观察，并用X射线光电子能谱进行了研究。结果表明：相对湿度从5%增加到100%时，摩擦系数从0.025增加到0.09，磨损率急剧下降，在相对湿度为40%时达到最小值，然后随着相对湿度的进一步增加而增加。Si 3 N4球上的富碳层的中断，以及在较高的相对湿度下的膜的摩擦诱导氧化被认为是摩擦系数增加的主要原因。此外，Si_3N_4球在较高相对湿度下的氧化和水解，导致在摩擦表面上形成主要由硅胶组成的摩擦化学膜，也被认为影响氢化DLC膜的摩擦和磨损行为。
Hydrogenated diamond-like carbon (DLC) films were deposited on Si (100) wafers by a plasma enhanced chemical vapour deposition technique using CH4 plus Ar as the feedstock. The friction and wear properties of the resulting films under different relative humidities, ranging from 5% to 100%, in a nitrogen environment, were measured using a ball-on-disc tribometer, with Si3N4 balls as the counterparts. The friction surfaces of the films and Si3N4 balls were observed on a scanning electron microscope, and investigated by x-ray photoelectron spectroscopy. The results showed that the friction coefficient increased continuously from 0.025 to 0.09 with increase in relative humidity from 5% to 100%, while the wear rate of the films sharply decreased and reached a minimum at a relative humidity of 40%, then it increased with further increase of the relative humidity. The interruption of the transferred carbon-rich layer on the Si3N4 ball, and the friction-induced oxidation of the films at higher relative humidity were proposed as the main reasons for the increase in the friction coefficient. Moreover, the oxidation and hydrolysis of the Si3N4 ball at higher relative humidity, leading to the formation of a tribochemical film, which mainly consists of silica gel, on the friction surface, are also thought to influence the friction and wear behaviour of the hydrogenated DLC films.