| 摘要: |
| 随着先进制造领域对高速钢材料切削性能和加工性能的要求越来越高，迫切需要利用氮化物薄膜来提高基体材料的硬度和耐磨性等综合性能，延长高速钢材料的使用寿命。通过 TiCrN 薄膜提升高速钢材料的使役性能，研究脉冲偏压占空比对 TiCrN 薄膜微观结构和性能的影响规律，实现薄膜沉积工艺的优化。采用电弧离子镀方法，通过改变脉冲偏压占空比在 M2 高速钢基体和单晶硅片上沉积 TiCrN 薄膜。研究发现，脉冲偏压占空比的增大有助于减少膜层表面大颗粒数量，改善膜层表面质量；占空比从 10%增加到 60%，TiCrN 薄膜厚度先增大后减小，30%占空比时，TiCrN 薄膜的厚度达到最大值 623.8 nm， 60%占空比时，TiCrN 薄膜的厚度达到最小值 517.4 nm。当脉冲偏压占空比为 10%时，Cr 元素含量为 33.9 at.%，晶粒尺寸达到最小值 12.692 nm，纳米硬度和弹性模量分别为 29.22 GPa 和 407.42 GPa。当脉冲偏压占空比为 30%时，Cr 元素含量达到最小值 33.07 at.%，此时 TiCrN 薄膜晶粒尺寸达到最大值 15.484 nm，纳米硬度达到最小值 25.38 GPa，稳定摩擦因数达到最大值 0.9。所制备的 TiCrN 薄膜均以（220）晶面为择优取向，晶粒尺寸在 12.692~15.484 nm，纳米硬度都在 25 GPa 以上， 是 M2 高速钢的 2.8 倍以上。在脉冲偏压占空比为 20%时，TiCrN 薄膜摩擦因数最小为 0.68，磨痕宽度为 0.63 mm，自腐蚀电位达到最大值-0.330 V（vs SCE），自腐蚀电流密度达到最小值 0.255 μA / cm2 ，腐蚀速率最低，耐腐蚀性能最强。与 M2 高速钢基体相比，TiCrN 薄膜的硬度、耐腐蚀和摩擦磨损性能都显著提升，Cr 元素和离子轰击作用是影响 TiCrN 薄膜性能的主要因素。研究结果为硬质薄膜工艺优化提供了一定的试验依据，TiCrN 薄膜在刀具材料性能提升方面有较好的应用前景。 |
| 关键词: 电弧离子镀 脉冲偏压占空比 TiCrN 薄膜 纳米硬度 耐蚀性 摩擦因数 |
| DOI：10.11933/j.issn.1007-9289.20221230001 |
| 分类号:TG156；TB114 |
| 基金项目:国家自然科学基金（51401182）；中国国家留学基金（CSC202108410274）；河南省科技攻关计划（222102220066）；河南省高层次人才国际化培养和郑州航空工业管理学院科研团队（23ZHTD01010）资助项目 |
|
| Effects of Pulsed Bias Duty Cycle on the Microstructure and Properties of TiCrN Films |
|
WEI Yongqiang1, GU Yanyang1, FAN Mengyuan1, YANG Jiale1, ZHANG Huasen1, ZHANG Xiaoxiao1, ZHONG Sujuan2, LIAO Zhiqian3
|
|
1.School of Aerospace Engineering, Zhengzhou University of Aeronautics, Zhengzhou 450046 , China;2.Zhengzhou Research Institute of Mechanical Engineering Co., Ltd., Zhengzhou 450001 , China;3.725Research & Development Institute of China Shipbuilding Industry Group Co., Ltd., Luoyang 471023 , China
|
| Abstract: |
| With the requirements of high-speed steel material cutting and machining are increasingly in high advanced manufacturing fields, there is an urgent need using nitride films to improve the hardness of the substrate materials and wear resistance and other comprehensive properties. Meanwhile the service life of high-speed steel materials is extended. The effects of the pulsed bias duty cycle on the microstructure and properties of TiCrN films were investigated to optimize the deposition process parameters and improve the properties of TiCrN films. TiCrN films subjected to different pulsed bias duty cycles were deposited onto M2 high-speed steel (HSS) substrates and Si wafers using the arc ion-plating method. The surface morphology, elemental composition, phase structure, and nanohardness of the TiCrN films were examined using scanning electron microscopy, energy-dispersive spectrometry, X-ray diffraction, and nanohardness indentation. The corrosion behaviors and tribological properties of the coated and uncoated M2 HSS samples were examined using an electrochemical workstation and a pin-on-disk tribometer at room temperature. Potentiodynamic polarization curves were used to calculate the self-corrosion potential and self-corrosion current density of the tested samples in a 3.5 wt.% NaCl solution. With an increase in the pulsed bias duty cycle from 10% to 60%, the amount of macroparticles on the TiCrN film surfaces decreased, and the surface quality improved. At pulsed bias duty cycle of 10%, the maximum amount of macroparticles was 175, whereas at pulsed bias duty cycle of 60%, the minimum amount of macroparticles was 85. The thicknesses of the TiCrN films ranged from 517.4 to 623.8 nm. The TiCrN film thickness showed a trend of increasing at pulsed bias duty cycles of 10%-30% and decreasing at pulsed bias duty cycles of 30%-60%. At pulsed bias duty cycle of 30%, the thickness of the TiCrN film reached the maximum value of 623.8 nm. At pulsed bias duty cycle of 60%, the minimum thickness was 517.4 nm. At pulsed bias duty cycle of 10%, the Cr content reached 33.9 at.%, the grain size of the TiCrN film reached the minimum of 12.692 nm, and the nanohardness and elastic modulus reached maximum values of 29.22 and 407.42 GPa, respectively. At pulsed bias duty cycle of 30%, the Cr content reached the minimum of 33.07 at.%, the grain size of the TiCrN film reached the maximum of 15.484 nm, the stable friction factor was 0.9, and the nanohardness reached the minimum of 25.83 GPa. All TiCrN films deposited under different pulsed bias duty cycles showed preferred orientations in the (220) crystal plane, and the diffraction peak intensity gradually increased as the pulsed bias duty cycle increased from 10% to 40%. However, the intensity of the (220) crystal orientation diffraction peak decreased when the pulsed bias duty cycle exceeded 40%. The nanohardness of the TiCrN films under different pulsed bias duty cycles exceeded 25 GPa, which is more than 2.8 times of that of M2 HSS. Potentiodynamic polarization curves showed that TiCrN films subjected to different pulsed bias duty cycles exhibited improved corrosion resistance. Compared with the M2 HSS substrate, the corrosion resistance of the TiCrN films showed that the corrosion potential increased by approximately 0.556-0.642 V, and the corrosion current density decreased by more than one order of magnitude. Friction factor curves plotted using the pin-on-disk wear test results, as well as optical microscopy observations of wear trace width and morphologies, indicated that the TiCrN films exhibited significant wear resistance compared to the uncoated M2 HSS substrate. The wear scars on the TiCrN films were more uniform, and the number of furrows decreased significantly. At pulsed bias duty cycle of 20%, the factor of friction and the abrasion width of the TiCrN films reached minimum values of 0.68 and 0.63 mm, respectively. The potentiodynamic polarization curve for the 20% cycle showed that the self-corrosion potential (Ecorr) of the TiCrN film reached the maximum of 0.330 V (vs. SCE), and the self-corrosion current density (icorr) reached the minimum value of 0.255 μA / cm2 . At pulsed bias duty cycle of 20%, the corrosion resistance was the highest, and the corrosion rate was the lowest. Compared with the M2 HSS substrate properties, the hardness, corrosion resistance, friction, and wear properties of the TiCrN films with different pulse bias duty cycles improved significantly. The Cr content and ion bombardment were the main factors that influenced the microstructure and properties of the TiCrN films. These results provide experimental basis for optimizing the hard films deposition process. TiCrN films have a better application future for the properties improvement of cutting tool materials. |
| Key words: arc ion plating pulsed bias duty cycle TiCrN films nano-hardness corrosion resistance factor of friction |
