Ni-W-P coatings were electrodeposited on copper substrates by pulse electroplating.Effects of electrolyte pH(1-3),temperature(40-80°C),average current density(1-7A/dm2)and pulse frequency(200-1000Hz)on deposition...Ni-W-P coatings were electrodeposited on copper substrates by pulse electroplating.Effects of electrolyte pH(1-3),temperature(40-80°C),average current density(1-7A/dm2)and pulse frequency(200-1000Hz)on deposition rate,structure and corrosion resistance performance of Ni-W-P coatings were studied by single factor method.Surface morphology,crystallographic structure and composition of Ni-W-P coatings were investigated by means of scanning electron microscopy,X-ray diffractometry and energy dispersive X-ray spectroscopy,respectively.Corrosion resistance performances of Ni-W-P coatings were studied by potentiodynamic polarization and electrochemical impedance spectroscopy in3.5%NaCl solution(mass fraction)and soil-containing solution.It was found that the pulse electroplated Ni-W-P coatings have superior corrosion resistance performance and the electroplating parameters significantly affect the structure and corrosion resistance performance of Ni-W-P coatings.The optimized parameters of pulse electroplating Ni-W-P coatings were as follows:pH2.0,temperature60°C,average current density4A/dm2,and pulse frequency600Hz.The Ni-W-P coating prepared under the optimized parameters has superior corrosion resistance(276.8kΩ)and compact surface without any noticeable defect.展开更多
A comparative study of amorphous electroless Ni-W-P coatings on mild steel substrate treated by a high power diode laser and furnace annealing was presented.Effects of different laser operating parameters and furnace-...A comparative study of amorphous electroless Ni-W-P coatings on mild steel substrate treated by a high power diode laser and furnace annealing was presented.Effects of different laser operating parameters and furnace-annealing conditions on microstructures,in terms of crystallisation,pores formation and grain growth,were investigated using SEM/EDX and XRD. Corrosion behaviours of these coatings before and after various treatments were evaluated with anodic polarisation in 0.5 mol/L H2SO4 solution.The results show that the furnace-annealing produces either a mixture of nanocrystallined Ni and amorphous phases or precipitated Ni3P phase distributed in nanocrystallined Ni-based matrix,depending on annealing temperatures,whilst the laser treatment under the operating conditions only produces nanocrystallined Ni-based matrix with Ni3P precipitates.Corrosion performance of the coatings treated by both the laser and the furnace-annealing is dependent on the annealing temperature and laser operating conditions.Corrosion mechanisms of various treated-coatings were discussed in the consideration of phase constitutes and proportion,grain sizes of both Ni and Ni3P phases,pores formation and residual stresses.展开更多
采用熔盐电沉积法制备了Ni/W复合层,通过扫描电镜和电子背散射衍射技术对Ni/W复合层的微观形貌、晶粒尺寸及小角度晶界频率进行了表征。结果表明：当电流密度为70~100 m A/cm2时,Ni/W复合层的表面平整光滑;Ni/W复合层的断裂方式为解理断...采用熔盐电沉积法制备了Ni/W复合层,通过扫描电镜和电子背散射衍射技术对Ni/W复合层的微观形貌、晶粒尺寸及小角度晶界频率进行了表征。结果表明：当电流密度为70~100 m A/cm2时,Ni/W复合层的表面平整光滑;Ni/W复合层的断裂方式为解理断裂;随电流密度增加,复合层厚度逐渐增加,晶粒尺寸减小,小角度晶界的频率降低。为复合材料获得较好的综合性能提供了可能。展开更多
文摘Ni-W-P coatings were electrodeposited on copper substrates by pulse electroplating.Effects of electrolyte pH(1-3),temperature(40-80°C),average current density(1-7A/dm2)and pulse frequency(200-1000Hz)on deposition rate,structure and corrosion resistance performance of Ni-W-P coatings were studied by single factor method.Surface morphology,crystallographic structure and composition of Ni-W-P coatings were investigated by means of scanning electron microscopy,X-ray diffractometry and energy dispersive X-ray spectroscopy,respectively.Corrosion resistance performances of Ni-W-P coatings were studied by potentiodynamic polarization and electrochemical impedance spectroscopy in3.5%NaCl solution(mass fraction)and soil-containing solution.It was found that the pulse electroplated Ni-W-P coatings have superior corrosion resistance performance and the electroplating parameters significantly affect the structure and corrosion resistance performance of Ni-W-P coatings.The optimized parameters of pulse electroplating Ni-W-P coatings were as follows:pH2.0,temperature60°C,average current density4A/dm2,and pulse frequency600Hz.The Ni-W-P coating prepared under the optimized parameters has superior corrosion resistance(276.8kΩ)and compact surface without any noticeable defect.
基金Project(Y2006F40) supported by the Natural Science Foundation of Shandong Province, ChinaProject(N00003) supported by UK Northwest Science Council through Northwest Laser Engineering Consortium (NWLEC)
文摘A comparative study of amorphous electroless Ni-W-P coatings on mild steel substrate treated by a high power diode laser and furnace annealing was presented.Effects of different laser operating parameters and furnace-annealing conditions on microstructures,in terms of crystallisation,pores formation and grain growth,were investigated using SEM/EDX and XRD. Corrosion behaviours of these coatings before and after various treatments were evaluated with anodic polarisation in 0.5 mol/L H2SO4 solution.The results show that the furnace-annealing produces either a mixture of nanocrystallined Ni and amorphous phases or precipitated Ni3P phase distributed in nanocrystallined Ni-based matrix,depending on annealing temperatures,whilst the laser treatment under the operating conditions only produces nanocrystallined Ni-based matrix with Ni3P precipitates.Corrosion performance of the coatings treated by both the laser and the furnace-annealing is dependent on the annealing temperature and laser operating conditions.Corrosion mechanisms of various treated-coatings were discussed in the consideration of phase constitutes and proportion,grain sizes of both Ni and Ni3P phases,pores formation and residual stresses.
文摘采用熔盐电沉积法制备了Ni/W复合层,通过扫描电镜和电子背散射衍射技术对Ni/W复合层的微观形貌、晶粒尺寸及小角度晶界频率进行了表征。结果表明：当电流密度为70~100 m A/cm2时,Ni/W复合层的表面平整光滑;Ni/W复合层的断裂方式为解理断裂;随电流密度增加,复合层厚度逐渐增加,晶粒尺寸减小,小角度晶界的频率降低。为复合材料获得较好的综合性能提供了可能。
