WS_2/TiB_2固体润滑涂层的结构及摩擦性能

Microstructure and friction properties of WS2/TiB_2 solid self-lubricant coating

运用多靶磁控溅射技术,将软质相的WS_2靶与硬质相的TiB_2靶共溅射制备出WS_2/TiB_2固体自润滑复合涂层。运用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对涂层截面的形貌及结构进行表征,并用纳米压痕仪和摩擦磨损试验机测试了涂层的硬度和摩擦磨损性能。结果表明,WS_2/TiB_2复合涂层截面的组织结构为柱状晶,且呈现TiB_2(001)择优取向,当WS_2靶功率从20 W增加至50 W时,TiB_2(001)衍射峰强度逐渐减弱,半高宽变宽,导致涂层的平均晶粒尺寸变小。当WS_2的功率超过60 W时,涂层的相结构发生由晶态到非晶态的转变。WS_2/TiB_2涂层具有较高的硬度(>20 GPa)和较低的摩擦因数(约0.2),即使是在相对湿度增加至50%的条件下,WS_2溅射功为40 W时,WS_2/TiB_2复合涂层仍旧具有非常低的磨损率6×10-16m3/(N·m),优于M2钢300多倍。

WS_2/TiB_2 solid self-lubricant coating was prepared by means of magnetron co-sputtering with TiB_2 and WS_2. Microstructure and morphologies of the coating were analyzed by X-ray diffraction（ XRD） and scanning electron microscopy（ SEM）. Hardness and friction wear properties were tested by nano indentation and friction wear testing machine,respectively. The results show that the WS_2/ TiB_2 coating has a columnar crystal structure and shows an obvious TiB_2（ 001） preferred orientation. With increasing of WS_2 target power from 20 to 50 W,the intensity of TiB_2（ 001） shows a descending trend,the FWHM becomes broader,and then lead to the small grain size. When the WS_2 target power exceed 60 W,the structure of coating change from columnar crystal to amorphous state. The WS_2/ TiB_2 coating has a high hardness（ 25 GPa） and a low friction coefficient（ 0. 2）. The wear rate of the WS_2/ TiB_2 coating with 40 W sputtering power reaches 6 × 10^-16m^3/N m（ 50% relative humidity）,which is more than 300 times better than that of M2 steel.