Mo和C含量对AlCrN薄膜组织和性能的影响

Effect of Mo and C Contents on the Crystal Structure and Properties of AlCrN Films

AlCrN薄膜因其具有优异的力学性能广泛应用于金属切削领域,Mo和C的掺杂对提高AlCrN薄膜的硬度和耐磨性有理论上的可行性,然而Mo和C元素的共同作用对AlCrN薄膜的组织结构、力学性能及摩擦学性能的影响仍须进一步探索。使用中频反应磁控溅射和热丝弧离子镀复合薄膜设备在硬质合金和Si(100)表面制备AlCr(MoC)N薄膜。使用SEM、XRD和EDS分析薄膜的微观形貌、物相组成和元素含量,采用纳米压痕测试仪、摩擦磨损试验仪和3D轮廓仪表征薄膜的硬度、耐磨损性并观察薄膜的磨痕形貌。结果表明:随着MoC镶嵌靶(Mo和C等面积)电流的增加,Mo和C元素含量上升,当MoC靶电流为2.5 A时,薄膜中Mo和C的含量分别升至约14.6 at%和9.1 at%。与AlCrN薄膜相比,AlCrMoCN薄膜中出现β-Mo_(2)N和γ-Mo_(2)N相,c-CrN相的生长从高表面能(111)面转变为低表面能(200)面。随着Mo和C元素含量的增加,薄膜硬度先增加后减小,靶电流为1 A时薄膜硬度达到最大值35±0.5 GPa,在MoC靶电流为2.5 A时,薄膜出现可由SEM观察到的纳米多层结构,此时AlCrMoCN薄膜硬度下降至约23±1 GPa。随着Mo和C元素含量的增加,薄膜的残余压应力由4.8±1 GPa减小至2.2±0.1 GPa。与无Mo和C薄膜相比,Mo和C的掺杂有利于降低AlCrN薄膜的摩擦因数,Mo和C含量增高,薄膜的摩擦因数大小呈现相近的趋势。AlCrMoCN薄膜在与SizN4对偶球对磨时获得相较于Al_(2)O_(3)对偶球更低的磨损率。对比分析AlCrN薄膜在不同Mo和C含量下的力学性能及摩擦学性能,揭示Mo和C的作用机理,可对其实际应用场景提供指导。

AlCrN is widely used as cutting tool coating because of its excellent mechanical properties.The doping of Mo and C is theoretically feasible to improve the hardness and wear resistance of AlCrN film,however,the effect of the combined effect of Mo and C elements on the structure,mechanical properties and tribological properties of AlCrN thin film stil needs to be further explored.AlCr(MoC)N films are grown on cemented carbides and Si(100)surfaces by using a hybrid PVD apparatus(medium frequency magnetron sputtering and ion platin evaporation).SEM and XRD and EDS are applied to analyze the crystal structure,phase,and elemental composition of the films.The hardness,tribological behavior,and wear track morphology are evaluated by nanoindentation tester,tribotester,and 3D profilometer,respectively.The results indicate that as the current of the MoC mosaic target(with equal area for Mo and C)increases,Mo and C content increases.As MoC target current reaches 2.5 A,Mo and C contents increase to around 14.6 at.%and 9.1 at.%,respectively.AlCrMoCN films are composed ofβ-Mo_(2)N andγ-Mo_(2)N phases,and the growth of the c-CrN phase changes from a high surface energy(111)plane to low surface energy(200)plane with the increasing content of Mo and C.With the increase of Mo and C content,the film hardness increases and then decreases,and the highest hardness of 35±0.5 GPa is achieved by the flm grown at the MoC target current of 1 A.As the MoC target current reaches 2.5 A,a multilayer structure is observed in SEM images,during which the hardness of AlCrMoCN film decreases to around 23±1 GPa.In addition,the compressive stress of the films decreases from 4.8±1 GPa to 2.2±0.1 GPa with the MoC target current increasing from 0 A to 2.5 A.The doping of Mo and C favors the reduction of the friction coefficient of AlCrN films compared to Mo and C free films,with increasing Mo and C content showing a similar trend in the magnitude of the fiction cofficient of the films.Lower wear rates for AlCrMoCN films are obtained when the Si_(3)N_(4)counterpart is used as compared to Al_(2)O_(3).A comparative analysis of the mechanical and tribological properties of AlCrN films at dfferent Mo and C contents reveals the mechanism of Mo and C effects and provides guides to practical application scenarios.