Preparation And Performance Research Of CrN Hard Film

Surface engineering, as a newly synthesis subject,has been progressed rapidly in recent years.It was proved that the application of surface engineering can excellently improve surface property of material,which can improve productibility and save resources.Experts predict that surface engineering will become one of the most predominant techniques in the future of 21 century.Technology of preparation for CrN film using hot-cathode ion-plating and the property of the film are investigated in the paper. XH-830 type ion plating equipment was used in the experiment. The processing parameter was optimized by orthogonal test. CrN film was deposited in the surface of GCrl5 type bearing steel and YG6 type hard alloy, and the main performance of the film was analyzed.Orthogonal test is a scientific experimental design method using orthogonal table to make arrangements for the experiment, which choose that of representation and typicalness from a large number of test point based on the principle of mathematical statistics and orthogonality. Orthogonal test is designed by choosing factors (minor arc current, matrix component voltage, partial pressure of nitrogen, depositional time, heating method) and level.The structural analysis of the film by X-ray diffraction(XRD) method shows that CrN film has been prepared using hot-cathode ion plating technology, and the films include CrN, Cr₂N and Cr phases. However, the phases in the film are different when the processing parameter changes. There are fcc CrN, hexagonal Cr₂N and orthogonal CrN in the film. Specially, orthogonal CrN has not been reported in other reference before, and its preferred orientation is (101) crystal face.Deposition rate and microhardness of the film as well as bond strength between the matrix and the film are tested in the paper. Range analysis and variance analysis of experimental findings were carried out, and the best technological conditions are obtained in this experiment. The highest microhardness is HV2338.The bonding strength between the matrix and the film is good, the highest strength is up to 73N, the highest deposition rate is 168nm/min. The performance of the film is depended on its the preparation technology, and they differ greatly with different technology.Observations on the surface and fracture of the film are performed by scanning electron microscope (SEM). As a result, it is founded that matrix component voltage has some sputtered effects on the film, sputter pit of the matrix surface increased with the component voltage increasing. The film and the matrix combined well according to the observation of the fracture, the film presented compact and fine columnar crystals.