In order to improve corrosion resistance of stainless steel 316L in warm acidic solution, Ni？Cu？P coatings with high copper and phosphorus contents were deposited onto stainless steel 316L substrates via electroless...In order to improve corrosion resistance of stainless steel 316L in warm acidic solution, Ni？Cu？P coatings with high copper and phosphorus contents were deposited onto stainless steel 316L substrates via electroless plating. The structure of the film and its resistance to corrosion in a warm acidic environment were investigated using scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction spectrometry （XRD）, polarization curves, electrochemical impedance spectroscopy （EIS）, and dipping corrosion tests, respectively. The results demonstrate that Ni？Cu？P coatings consist of two types of nodules, which are 19.98% Cu and 39.17% Cu （mass fraction） respectively. The corrosion resistance of the 316L substrate when subjected to a warm acidic solution is significantly improved by the addition of the new type of the Ni？Cu？P coating. The as-plated coatings demonstrate better corrosion resistance than annealed coatings. As-plated coatings and those annealed at 673 K are found to corrode selectively, while pitting is observed to be the main corrosion mechanism of coatings annealed at 773 and 873 K.展开更多
In consideration of the special environmental conditions of coal equipment in mining, the seamless steel tube of hy-draulic prop made of 20^# carbon steel was taken as the substrate, and 316L stainless steel powder wa...In consideration of the special environmental conditions of coal equipment in mining, the seamless steel tube of hy-draulic prop made of 20^# carbon steel was taken as the substrate, and 316L stainless steel powder was used to clad the sub-strate by a fiber-coupled semiconductor laser. The microstructure of the cladding layer was determined by metalloscope. The hardness, wear resistance and corrosion resistance of the cladding layer were measured. The results show that metallurgy bind-ing interface between the cladding layer and the substrate is obtained without defects such as cracks and pores. The hardness of the cladding layer is much higher than that of the matrix, and the wear resistance and corrosion resistance are simultaneously better. According to the analysis, it is summarized that the improvement in performance of the cladding layer is closely related to the change of microstructure and the thermal effect in the cladding process. The maximum hardness occurs in the equiaxed zone, and with the grain coarsening, the hardness reduces simultaneously. In addition, the precipitated phase, hard particles and trace elements also have a great influence on the properties of the cladding layer, and they will prevent the surface from ab-rasion and reduce the plastic deformation of the matrix. It is verified that the 316L stainless steel is suitable for the 20^# steel in laser cladding repairing process. Since this study focused on coal machine equipment parts, it has certain practical significance for the repair of hydraulic equipment.展开更多
Ni-P/SiC/PTFE coating was obtained on the surface of 316L stainless steel by electrodeposition of Ni-P/SiC coating and immersion of PTFE(polytetrafluoroethylene).The surface morphology and composition were analyzed by...Ni-P/SiC/PTFE coating was obtained on the surface of 316L stainless steel by electrodeposition of Ni-P/SiC coating and immersion of PTFE(polytetrafluoroethylene).The surface morphology and composition were analyzed by scanning electron microscope and energy dispersive spectrometer.The corrosion resistance of the coating in 0.5 mol/L H2SO4+2×10−6 HF solution was studied by electrochemical method.Surface contact angle was used to test the hydrophobic properties of the coating.The results indicated that the Ni-P/SiC/PTFE coating prepared on the surface of stainless steel was uniform and compact,which significantly improved the self-corrosion potential of stainless steel.The self-corrosion current density decreased from 7.62 to 0.008μA/cm2.The durability performance of coating was tested under 0.6 V voltage and the stable corrosion current density value was 0.19μA/cm2,then wetting angle was tested after durability experiment and the value is 134.5°.展开更多
Pd-Ni coating shows good corrosion resistance in strong corrosion environments.However,in complex aggressiveenvironments,the performance of the coatings is limited and further improvement is necessary.The effects of t...Pd-Ni coating shows good corrosion resistance in strong corrosion environments.However,in complex aggressiveenvironments,the performance of the coatings is limited and further improvement is necessary.The effects of the applied platingcurrent density on the composition,structure and properties of Pd-Ni coatings were studied.By changing the current density in thesame bath,multi-layer Pd-Ni coatings were prepared on316L stainless steel.Scanning electronic microscopy,weight loss tests,adhesion strength,porosity and electrochemical methods were used to study the corrosion resistance of the films prepared bydifferent coating methods.Compared with the single layer Pd-Ni coating,the multi-layer coatings showed higher microhardness,lower internal stress,lower porosity and higher adhesive strength.The multi-layer Pd-Ni coating showed obviously better corrosionresistance in hot sulfuric acid solution containing Cl-.展开更多
基金Project(CKJA201202)supported by the Innovation Fund Key Project of Nanjing Institute of Technology,ChinaProject(51301088)supported by the National Natural Science Foundation of China
文摘In order to improve corrosion resistance of stainless steel 316L in warm acidic solution, Ni？Cu？P coatings with high copper and phosphorus contents were deposited onto stainless steel 316L substrates via electroless plating. The structure of the film and its resistance to corrosion in a warm acidic environment were investigated using scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction spectrometry （XRD）, polarization curves, electrochemical impedance spectroscopy （EIS）, and dipping corrosion tests, respectively. The results demonstrate that Ni？Cu？P coatings consist of two types of nodules, which are 19.98% Cu and 39.17% Cu （mass fraction） respectively. The corrosion resistance of the 316L substrate when subjected to a warm acidic solution is significantly improved by the addition of the new type of the Ni？Cu？P coating. The as-plated coatings demonstrate better corrosion resistance than annealed coatings. As-plated coatings and those annealed at 673 K are found to corrode selectively, while pitting is observed to be the main corrosion mechanism of coatings annealed at 773 and 873 K.
基金Key Research and Development Project of Shanxi Province(No.201603D121002-2)
文摘In consideration of the special environmental conditions of coal equipment in mining, the seamless steel tube of hy-draulic prop made of 20^# carbon steel was taken as the substrate, and 316L stainless steel powder was used to clad the sub-strate by a fiber-coupled semiconductor laser. The microstructure of the cladding layer was determined by metalloscope. The hardness, wear resistance and corrosion resistance of the cladding layer were measured. The results show that metallurgy bind-ing interface between the cladding layer and the substrate is obtained without defects such as cracks and pores. The hardness of the cladding layer is much higher than that of the matrix, and the wear resistance and corrosion resistance are simultaneously better. According to the analysis, it is summarized that the improvement in performance of the cladding layer is closely related to the change of microstructure and the thermal effect in the cladding process. The maximum hardness occurs in the equiaxed zone, and with the grain coarsening, the hardness reduces simultaneously. In addition, the precipitated phase, hard particles and trace elements also have a great influence on the properties of the cladding layer, and they will prevent the surface from ab-rasion and reduce the plastic deformation of the matrix. It is verified that the 316L stainless steel is suitable for the 20^# steel in laser cladding repairing process. Since this study focused on coal machine equipment parts, it has certain practical significance for the repair of hydraulic equipment.
基金Project(2018YFB1502500)supported by the National Key Research and Development Program of ChinaProject supported by State Key Laboratory of Powder Metallurgy,Central South University,China+1 种基金Projects(2020JJ5100,2018JJ3101)supported by Natural Science Foundation of Hunan Province,ChinaProject(51671085)supported by the National Natural Science Foundation of China。
文摘Ni-P/SiC/PTFE coating was obtained on the surface of 316L stainless steel by electrodeposition of Ni-P/SiC coating and immersion of PTFE(polytetrafluoroethylene).The surface morphology and composition were analyzed by scanning electron microscope and energy dispersive spectrometer.The corrosion resistance of the coating in 0.5 mol/L H2SO4+2×10−6 HF solution was studied by electrochemical method.Surface contact angle was used to test the hydrophobic properties of the coating.The results indicated that the Ni-P/SiC/PTFE coating prepared on the surface of stainless steel was uniform and compact,which significantly improved the self-corrosion potential of stainless steel.The self-corrosion current density decreased from 7.62 to 0.008μA/cm2.The durability performance of coating was tested under 0.6 V voltage and the stable corrosion current density value was 0.19μA/cm2,then wetting angle was tested after durability experiment and the value is 134.5°.
文摘Pd-Ni coating shows good corrosion resistance in strong corrosion environments.However,in complex aggressiveenvironments,the performance of the coatings is limited and further improvement is necessary.The effects of the applied platingcurrent density on the composition,structure and properties of Pd-Ni coatings were studied.By changing the current density in thesame bath,multi-layer Pd-Ni coatings were prepared on316L stainless steel.Scanning electronic microscopy,weight loss tests,adhesion strength,porosity and electrochemical methods were used to study the corrosion resistance of the films prepared bydifferent coating methods.Compared with the single layer Pd-Ni coating,the multi-layer coatings showed higher microhardness,lower internal stress,lower porosity and higher adhesive strength.The multi-layer Pd-Ni coating showed obviously better corrosionresistance in hot sulfuric acid solution containing Cl-.
