钛合金表面大气压等离子体枪制备类金刚石薄膜

Diamond-like Carbon Thin Films Deposited on Ti6Al4V Alloy Surface by Plasma Gun at Atmospheric Pressure

摘要:

在大气下，采用大气压介质阻挡放电（DBD）等离子体枪在低温下（<350 ℃），以甲烷为单体，氩气为工作气体，在Ti6Al4V钛合金表面制备一层类金刚石薄膜（DLC），以期改善钛合金表面摩擦学性能。利用激光拉曼（Raman）光谱和X射线光电子能谱（XPS）分析了所制备DLC薄膜的结构；利用扫描电子显微镜（SEM）观察DLC薄膜的表面形貌；利用划痕仪测量了DLC薄膜与基体的结合力；利用球-盘摩擦磨损实验仪对DLC薄膜的耐磨性能进行了研究。结果表明：在本实验工艺条件下沉积的类金刚石薄膜厚度约为1.0 μm，薄膜均匀且致密，表面粗糙度Ra为13.23 nm。类金刚石薄膜与基体结合力的临界载荷达到31.0 N。DLC薄膜具有优良的减摩性，Ti6Al4V表面沉积DLC薄膜后摩擦系数为0.15，较Ti6Al4V基体的摩擦系数0.50明显减小，耐磨性能得到提高。

Abstract:

At atmospheric pressure, diamond-like carbon (DLC) thin films were deposited on the Ti6Al4V alloy surface by a DBD plasma gun at low temperature (<350 oC), with CH4 as a precursor and Ar as dilution gas. The structure of the DLC thin film was analyzed by Laser Raman spectroscope and X-ray photoelectron spectroscopy. The surface morphology was observed through scanning electron microscopy. The adhesion between the DLC thin film and the substrate was investigated with the scribe testing. The friction and wear behavior of the DLC thin films under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results show that it is feasible to prepare a DLC thin film of 1.0 μm thickness by a plasma gun. The film is uniform and dense and the surface roughness Ra is about 13.23 nm. The critical load of adhesion force between the DLC thin film and the substrate is 31.0 N. It has been found that the DLC thin film has excellent friction- and wear-resistant behavior. The friction coefficient of the Ti6Al4V substrate is about 0.50 under dry sliding against steel, while the DLC thin film experiences much abated friction coefficient to 0.15 under the same testing condition.