磁控溅射CrAlSiN膜层的高温性能研究

Study on High Temperature Performance of Magnetron Sputtered CrAlSiN Film

为了探究高速钢在高速切削时的高温氧化行为,采用磁控溅射技术在高速钢表面沉积CrAlSiN硬质膜并进行高温氧化试验,高温氧化温度分别为700,800,900,1 000℃,保温时间为1 h。分别利用X射线衍射仪、扫描电镜、能谱仪、纳米压痕仪对膜层的微观结构、纳米硬度及模量、磨损率和抗氧化性进行表征及分析。结果表明:CrAlSiN膜层为fcc-CrN结构,纳米硬度、模量和磨损率分别为24.87 GPa、300.51 GPa和0.024 nm/mN。氧化过程中高温氧化温度为700℃时膜层表面产生微裂纹,形成Cr2O3和Al2O3混合氧化层;800℃时出现微量细小的白色颗粒状氧化物;900℃时,微裂纹增长,氧化物数量增多,新增Cr2O3衍射峰;1 000℃时元素扩散剧烈,但未检测到有基体元素扩散至膜层表面,表明膜层仍具有较好的抗氧化性。随着氧化温度的升高,薄膜表面产生裂纹和氧化物,使膜层的纳米硬度、模量降低,磨损率升高。

In order to investigate the high temperature oxidation behaviour of high-speed steel during high speed cutting, a CrAlSiN hard film was deposited on the surface of high-speed steel by magnetron sputtering, and a high-temperature oxidation test was carried out on it at temperatures of 700,800,900,1 000 ℃ with a holding time of 1 h. Additionally, the microstructure, nano hardness and modulus, wear rate and oxidation resistance of the film were characterized and analyzed by X-ray diffractometer, scanning electron microscope, energy dispersive spectrometer and nanoindentor. Results showed that the CrAlSiN film had a fcc-CrN structure, and the nano hardness, modulus and wear rate were 24.87 GPa, 300.51 GPa and 0.024 nm/mN respectively. During the oxidation process, when the temperature for high temperature oxidation was 700 ℃, microcracks formed on the surface of the film and an oxide layer composed of Cr2O3and Al2O3took shape;at 800 ℃, a small amount of fine white granular oxide appeared;at 900 ℃, microcracks grew, the number of oxides increased, and new Cr2O3diffraction peaks appeared;at 1 000 ℃, the element diffusion was intense, however no matrix elements diffused onto the surface of the film, indicating that the film still had good oxidation resistance. In general, with the increase of oxidation temperature, cracks and oxides appeared on the surface of the film, which reduced the nano hardness and modulus of the film and increased the wear rate.