脉冲电源占空比对电弧离子镀AlCrN涂层结构和性能的影响

Effects of Duty Cycle on Structures and Properties of AlCrN Coatings Deposited by Pulsed Arc Ion Plating

目的研究阴极电弧离子镀脉冲电源占空比对AlCrN涂层结构和性能的影响,优化工艺参数,以提高涂层的性能。方法采用脉冲电弧离子镀制备不同占空比AlCrN涂层,利用扫描电子显微镜(SEM)、原子力显微镜(AFM)、X射线衍射仪(XRD)、纳米压痕仪和Chi650e电化学工作站,表征涂层的结构、力学性能和耐蚀性能。结果随着占空比的增加,涂层表面颗粒面积分数和粗糙度先逐渐增加,当占空比大于20%后,颗粒面积分数趋于平稳,同时涂层的厚度从4.06μm逐渐增加到7.56μm。当占空比低于20%时,涂层中存在较多的孔隙;当占空比大于20%后,涂层中的孔隙较少,涂层结构较为致密。XRD结果表明,AlCrN涂层为立方结构,晶粒尺寸在14.9~18 nm之间。涂层硬度和结合力均随占空比先增加后减小,占空比为25%时,硬度可达35.19 GPa,结合力为81.7 N。占空比为25%时,涂层的自腐蚀电位较高,自腐蚀电流密度最小,表明该涂层的耐蚀性较强。结论适当地提高脉冲电源占空比可降低涂层中孔隙的含量,提高涂层的硬度和膜基结合力,同时提高涂层的抗腐蚀性。

Effects of duty cycle on the structures and properties of AlCrN coatings were investigated for improving the performances.The AlCrN coatings were synthesized by pulsed arc ion plating under different power duty cycles in nitrogen ambient.The structures,mechanical properties and corrosion resistance of the coatings were characterized by scanning electron microscopy(SEM),atomic force microscopy(AFM),X-ray diffractometry(XRD),nanoindentation and Chi650e electrochemical workstation.The results showed that the surface particle area fraction and roughness of the coatings gradually increased with the increase of duty cycles from 10%to 20%,then tended to be stable when further improved the duty cycles.While the thicknesses of the AlCrN coatings increased from 4.06μm to 7.56μm with the duty cycles increasing from 10%to 30%.When the duty cycles was less than 20%,there were many pores in the coatings;when the duty cycles was greater than 20%,the pores in the coatings were less,and the coating structure was denser.The XRD results showed that the AlCrN coatings had a cubic structure and contained nano-grains with size between 14.9~18 nm.Both the hardness and adhesion strength first increased with the duty cycles,and reached the largest values of 35.19 GPa and 81.7 N at duty cycle of 25%,then decresed with the higher duty cycles.The coating at the duty cycle of 25%exhibited the lowest self-corrosion current density and a high self-corrosion potential,indicating the excellent corrosion resistance of the coating.These results suggested that a reasonable high duty cycles could decrease the number of poles in the coaitngs and enhance the mechanical and corrosion resistance performances.