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采用高压直流等离子体氮化技术,对医用锻造钴铬钼合金进行表面氮化处理,考察了氮化温度及时间对钴铬钼合金摩擦性能及润湿性能的影响。运用X射线衍射仪及场发射扫描电镜分析氮化层物相组成及表面微观结构;用显微硬度计和光学动/静态接触角仪测试合金表面显微硬度及接触角数值;利用球-盘摩擦试验机在干摩擦条件下对氮化层的摩擦磨损性能进行测试。结果表明:钴铬钼合金试样经直流等离子体氮化处理后,氮化层厚度、表面粗糙度及显微硬度值显著增加,亲水性能及耐磨损性能得到明显改善。在较低的氮化温度及较短的氮化时间内,氮化试样物相主要由σ-CoCr相及CrN相组成;随着氮化温度及时间的增加,氮化试样物相中还检测到硬质化合物相Cr_2N。与未处理试样相比,氮化试样的磨损率及磨痕宽度减小,氮化参数为800°C/8 h时磨损率最低,磨痕宽度最窄,耐磨损性能最佳。
The high-voltage direct current plasma nitriding technology was used to surface nitriding the medical forged cobalt-chromium-molybdenum alloy. The influence of nitriding temperature and time on the tribological properties and wetting properties of the cobalt-chromium-molybdenum alloy was investigated. The phase composition and surface microstructure of the nitride layer were analyzed by X-ray diffraction and field emission scanning electron microscopy. The microhardness and optical dynamic / static contact angle were used to test the microhardness and contact angle of the alloy surface. Friction Tester The friction and wear properties of nitrided layer were tested under dry friction conditions. The results show that the nitrided layer thickness, surface roughness and microhardness increase significantly after the DC plasma nitriding treatment, and the hydrophilic property and wear resistance can be obviously improved. At lower nitriding temperature and shorter nitriding time, the phase of nitriding sample mainly consists of σ-CoCr phase and CrN phase. With the increase of nitriding temperature and time, Hard phase Cr_2N was also detected. Compared with the untreated sample, the wear rate and wear scar width of the nitrided sample are reduced. When the nitriding parameter is 800 ° C / 8 h, the wear rate is the lowest, the wear scar width is the narrowest, and the wear resistance is the best.