脉冲偏压频率对TiSiN薄膜的微观结构和性能的影响

采用脉冲偏压电弧离子镀技术,通过改变脉冲偏压频率在M2高速钢基体上沉积TiSiN薄膜,利用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)等仪器,研究脉冲偏压频率对TiSiN薄膜的表面和截面形貌、元素成分、相结构的影响,并通过纳米压痕仪测试了TiSiN薄膜的纳米硬度和弹性模量。在统计的视场内(9×10³ μm²),TiSiN薄膜表面的大颗粒直径在0.30~7.26 μm之间,脉冲偏压频率从40 kHz到60 kHz,数量由495个减少到356个,之后随着脉冲偏压频率增加到80 kHz,大颗粒数量又增加到657个;当脉冲偏压频率为60 kHz时,TiSiN薄膜表面大颗粒和微坑缺陷数量最少,Si原子含量达到最小值0.46%;脉冲偏压频率为50 kHz时,TiSiN薄膜以非柱状晶的结构进行生长,厚度达到最小值1.63 μm;脉冲偏压频率为60 kHz时,柱状晶结构细化,薄膜的致密度增加。不同脉冲偏压频率下TiSiN薄膜都在(111)晶面位置出现择优取向,Si以非晶态Si₃N₄的形式存在于TiSiN薄膜中,没有检测到Si的峰值,形成了TiN晶体和Si₃N₄非晶态的复合结构。脉冲偏压频率60 kHz下TiSiN薄膜的表面大颗粒最少,纳米硬度达到最大值34.56 GPa,比M2高速钢基体的硬度提高了约3倍。当脉冲偏压频率为50 kHz时,TiSiN薄膜的腐蚀电位达到最大值－0.352 V(vs SCE),比基体提高了723 mV,自腐蚀电流密度达到0.73 μA/cm²;当脉冲偏压频率为70 kHz时,TiSiN薄膜的腐蚀电位达到－0.526 V(vs SCE),自腐蚀电流密度达到最小值 0.66 μA/cm²。

Effect of pulsed bias frequency on microstructure and properties of TiSiN film

Pulsed bias arc ion plating technology was used to deposit TiSiN film on M2 high-speed steel substrate by changing pulsed bias frequency. Effect of pulsed bias frequency on surface and cross-sectional morphologies, element composition and phase structure of the TiSiN films, and the nanohardness and elastic modulus of the TiSiN films were tested by means of nanoindenter, scanning electron microscope (SEM), energy spectrometer (EDS), X-ray diffractometer (XRD) and other instruments. Within the statistical field of view(9×10³ μm²), the macro-particle diameter on the surface of the TiSiN films varies between 0.30 and 7.26 μm. With the increase of pulsed bias frequency from 40 kHz to 60 kHz, the number of macro-particles on the surface of the TiSiN films reduces from 495 to 356. As the pulsed bias frequency increases to 80 kHz, the number of macro-particles increases to 657. With the pulsed bias frequency of 60 kHz, the numbers of macro-particles and micro-pit defects on the surface of the TiSiN films are the least and the Si atom content reaches the minimum value of 0.46%. When the pulsed bias frequency is 50 kHz, the TiSiN films grow in a non-columnar structure, and the thickness reaches the minimum value of 1.63 μm. When the pulsed bias frequency is 60 kHz, the columnar crystal structure is refined, and the density of the films increases. The TiSiN films has a preferred orientation at the (111) crystal plane under different pulsed bias frequencies, but no Si peak is detected. Amorphous Si₃N₄ exists in the TiSiN films, the TiN crystals and Si₃N₄ amorphous structure form the composite structure. At the pulsed bias frequency of 60 kHz, the mount of the macro-particles on the TiSiN films surface reaches the minimum value. The nanohardness of the TiSiN films at the pulsed bias frequency of 60 kHz reaches 34.56 GPa, which is about three times higher than that of the M2 high-speed steel substrate. When the pulsed bias frequency is 50 kHz, the corrosion potential of the TiSiN film reaches the maximum value －0.352 V(vs SCE), which is 723 mV higher than that of the substrate, and the corrosion current density reaches the value of 0.73 μA/cm². When the pulsed bias frequency is 70 kHz, the corrosion potential of the TiSiN film reaches the value －0.526 V(vs SCE), and the corrosion current density reaches the minimum value of 0.66 μA/cm².