Corrosion property of copperized layer on Zr formed by double glow plasma surface alloying technique

Zr and its alloys have excellent mechanical properties as new structural material,but in specific application environment,its corrosion resistance still needs to be further explored.In this work,double glow plasma surface alloying technique was used for copperizing on pure Zr surface.Besides,X-ray diffraction（XRD）,scanning electron microscope（SEM） and energy dispersion spectrum（EDS） were employed to characterize the samples.Furthermore,research was also conducted on the polarization curve of the samples in different solutions.Copperizing on surface can improve corrosion resistance of pure Zr in 3.5 % Na Cl and 0.5 moláL-1Na OH solutions.Especially in 0.5 moláL-1Na OH solution,the corrosion resistance can achieve significant improvement.However,copperizing has no influence on the improvement of corrosion resistance of pure Zr in 0.5 moláL-1H2SO4 solution.The results may provide new insight into way for improving the corrosion property of zirconium alloys.

Cooperative effect of surface alloying and laser texturing on tribological performance of lubricated surfaces

The cooperative effect of laser surface texturing(LST) and double glow plasma surface alloying on tribological performance of lubricated sliding contacts was investigated.A Nd:YAG laser was used to generate microdimples on steel surfaces. Dimples with the diameter of 150μm and the depth of 30-35μm distributed circumferentially on the disc surface.The alloying element Cr was sputtered to the laser texturing steel surface by double glow plasma technique.A deep diffusion layer with a thickness of 30μm and a high hardness of HV900 was formed in this alloy.Tribological experiments of three types of samples(smooth,texturing and texturing+alloying) were conducted with a ring-on-disc tribometer to simulate the face seal.It is found that,in comparison with smooth steel surfaces,the laser texturing samples significantly reduce the friction coefficient.Moreover,the lower wear rate of the sample treated with the two surface techniques is observed.

Tribological Properties of Dimpled Surface Alloying Layer on Carbon Steel

The effect of surface structure and coating on tribological properties of 45^# carbon steel disc was analyzed. A Nd：YAG laser was used to generate rnicrodirnples on steel surfaces. Dimples with diameter of 150 rn and depth of 50 rn were distributed in an orbicular array on disc surface. Then the alloying element Mo was sputtered to 45# carbon steel disc surface by means of double glow plasma technology. Diffusion Mo alloying layer with 30min thickness and high hardness up to 0.025 was formed on the disc surface. Tribological experiments of three types samples （smooth, texturing and texturing＋alloying） were conducted with a pin-on-disc tribometer. It is found that the dimpled-samples are most effective for reducing friction in comparison with smooth steel surthces, improving the lubricating state from boundary to hydrodynamic region.

Study on preparation,microstructure and luminescent properties of Er-ZrO_2 layer

To further explore the material early-warning application of the luminescent coating, we demonstrated a new method by preparing a mixture layer of metallic erbium and oxidized zirconium （Er-ZrO2 layer） using the double glow plasma surface alloying technology with Zr and Er co-sputtering under oxygen plasma exposure. The microstructure, composition and luminescence proper-ties of the layers were characterized by scanning electron microscopy, X-ray diffraction, Raman and photoluminescence spectra. The dependence of the luminescence on the gradual concentration was studied. Results indicated that the contents of Zr, Er and O in the layer decreased gradually along the depth direction. The luminescence properties were concentration-dependent. X-ray dif-fraction analysis showed that the crystalline structure of ZrO2 layer transferred from a mixture phase of tetragonal and monoclinic to pure monoclinic phase with the Zr-Er co-sputtering. The Raman bands of the layers depended on its local ZrO2crystal struc-tures. Photoluminescence characteristics of Er-ZrO2layer revealed that the main emission bands were assigned to2H11/2→4I15/2and 4S3/2→4I15/2transition under the excitation at 325 nm. The fact suggested that the plasma surface alloying is an effective method to obtain luminescent layer.