CrN films were deposited on the high-speed-steel substrates by arc ion plating. The effect of an axial magnetic field on the microstructure and mechanical properties was investigated. The chemical composition, microst...CrN films were deposited on the high-speed-steel substrates by arc ion plating. The effect of an axial magnetic field on the microstructure and mechanical properties was investigated. The chemical composition, microstructure, surface morphology, surface roughness, hardness and film/substrate adhesion of the film were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope（SEM）, surface morphology analyzer, Vickers microhardness test and scratch test. The results showed that the magnetic field puts much effect on the microstructure,chemical composition, hardness and film/substrate adhesion of the Cr N films. The N content increases and Cr content decreases when the magnetic flux density increases from 0 to 30 m T. All of the Cr N films were found to be substoichiometric. With an increase in the magnetic flux density, the film structures change in such way： Cr_2N →Cr_（2-N）＋CrN→CrN＋Cr_2N→CrN.The SEM results showed that the number of macroparticles（MPs） on the film surface is significantly reduced when the magnetic flux density increases to 10 mT or higher. The surface roughness decreases with the magnetic field, which is attributed to the fewer MPs and sputtered craters on the film surface. The hardness value increases from 2074 HV_（0.025） at 0 mT（without magnetic field） and reaches a maximum value of 2509 HV_（0.025） at 10 m T.The further increase in the magnetic flux density leads to a decrease in the film hardness. The critical load of film/substrate adhesion shows a monotonous increase with the increase in magnetic flux density.展开更多
With the development of industry, much attention has been paid to lengthening the life span of bearings. As reported in this paper, we investigated the Cr/CrN compound films formed on the specimens of W9Cr4V2Mo bearin...With the development of industry, much attention has been paid to lengthening the life span of bearings. As reported in this paper, we investigated the Cr/CrN compound films formed on the specimens of W9Cr4V2Mo bearing steel by ion beam assisted deposition for improving the performance of bearing steels. The Vicker＇s microhardness, pin-on-disc, electrochemical measurement, XRD and SEM tests were used to characterize and analyze the treated samples. All results indicated that the mechanical properties of the treated samples were good, with the microhardness greater than that of the uncoated specimen, and the wear resistance, the passivity and pitting corrosion resistance increased considerably, the films possessed alternate Cr and CrN compound phases and produced different effects on the improvement of the performance of W9Cr4V2Mo bearing steels with different composing phases.展开更多
The reliability of a substrate curvature-based stress measurement method for CrN thin films on substrate with fluctuant surface was discussed.The stress error led by the ignorance of substrate thermal deformation was ...The reliability of a substrate curvature-based stress measurement method for CrN thin films on substrate with fluctuant surface was discussed.The stress error led by the ignorance of substrate thermal deformation was studied.Results showed that this error could be as large as several hundred MPa under general deposition conditions.Stress in the CrN thin films with different thicknesses ranging from 110 to 330 nm on stainless steel was studied by this method,in comparison with conventional results on silicon wafer.The thin films＇ morphology and structure were investigated and related to the film stress.A significant result of the comparison is that stress evolution in the thin films on steel obviously differs from that on silicon wafer,not only because the two substrates have different coefficients of thermal expansion,which provokes thermal stress,but also the considerable discrepancy in the thin films＇ grain coarsening rate and structure that induce different intrinsic stresses.展开更多
基金supported by Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Dalian University of Technology)Ministry of Education (Grant No. LABKF1405)
文摘CrN films were deposited on the high-speed-steel substrates by arc ion plating. The effect of an axial magnetic field on the microstructure and mechanical properties was investigated. The chemical composition, microstructure, surface morphology, surface roughness, hardness and film/substrate adhesion of the film were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope（SEM）, surface morphology analyzer, Vickers microhardness test and scratch test. The results showed that the magnetic field puts much effect on the microstructure,chemical composition, hardness and film/substrate adhesion of the Cr N films. The N content increases and Cr content decreases when the magnetic flux density increases from 0 to 30 m T. All of the Cr N films were found to be substoichiometric. With an increase in the magnetic flux density, the film structures change in such way： Cr_2N →Cr_（2-N）＋CrN→CrN＋Cr_2N→CrN.The SEM results showed that the number of macroparticles（MPs） on the film surface is significantly reduced when the magnetic flux density increases to 10 mT or higher. The surface roughness decreases with the magnetic field, which is attributed to the fewer MPs and sputtered craters on the film surface. The hardness value increases from 2074 HV_（0.025） at 0 mT（without magnetic field） and reaches a maximum value of 2509 HV_（0.025） at 10 m T.The further increase in the magnetic flux density leads to a decrease in the film hardness. The critical load of film/substrate adhesion shows a monotonous increase with the increase in magnetic flux density.
基金The project supported by National Natural Science Foundation of China (No. 90205001)
文摘With the development of industry, much attention has been paid to lengthening the life span of bearings. As reported in this paper, we investigated the Cr/CrN compound films formed on the specimens of W9Cr4V2Mo bearing steel by ion beam assisted deposition for improving the performance of bearing steels. The Vicker＇s microhardness, pin-on-disc, electrochemical measurement, XRD and SEM tests were used to characterize and analyze the treated samples. All results indicated that the mechanical properties of the treated samples were good, with the microhardness greater than that of the uncoated specimen, and the wear resistance, the passivity and pitting corrosion resistance increased considerably, the films possessed alternate Cr and CrN compound phases and produced different effects on the improvement of the performance of W9Cr4V2Mo bearing steels with different composing phases.
文摘The reliability of a substrate curvature-based stress measurement method for CrN thin films on substrate with fluctuant surface was discussed.The stress error led by the ignorance of substrate thermal deformation was studied.Results showed that this error could be as large as several hundred MPa under general deposition conditions.Stress in the CrN thin films with different thicknesses ranging from 110 to 330 nm on stainless steel was studied by this method,in comparison with conventional results on silicon wafer.The thin films＇ morphology and structure were investigated and related to the film stress.A significant result of the comparison is that stress evolution in the thin films on steel obviously differs from that on silicon wafer,not only because the two substrates have different coefficients of thermal expansion,which provokes thermal stress,but also the considerable discrepancy in the thin films＇ grain coarsening rate and structure that induce different intrinsic stresses.
