采用动电位扫描、扫描电子显微镜和X-射线衍射分析分别研究了不同质量浓度的糖精和1,4-丁炔二醇对镍电沉积层的极化作用、表面形貌及晶体取向的影响。结果表明:在瓦特镀镍液中加入糖精和1,4-丁炔二醇,极化曲线均向负电位方向移动。糖精...采用动电位扫描、扫描电子显微镜和X-射线衍射分析分别研究了不同质量浓度的糖精和1,4-丁炔二醇对镍电沉积层的极化作用、表面形貌及晶体取向的影响。结果表明:在瓦特镀镍液中加入糖精和1,4-丁炔二醇,极化曲线均向负电位方向移动。糖精质量浓度增加至2.0 g/L时,极化曲线不再向负电位方向移动,镀层呈现(200)面择优取向。当1,4-丁炔二醇质量浓度增加到0.5 g/L时,其显著提高了镍电沉积过电位230 m V,有效增大成核密度,其镀层微观形貌平整均匀,择优取向并未发生改变。展开更多
A new type of electroplating bath suitable for nickel electrodeposition was developed. Trisodium citrate was used as a complexing agent and a buffer in the bath. The buffering capacity between trisodium citrate and bo...A new type of electroplating bath suitable for nickel electrodeposition was developed. Trisodium citrate was used as a complexing agent and a buffer in the bath. The buffering capacity between trisodium citrate and boric acid were compared. The effects were investigated under different conditions of bath composition, current density, pH and temperature on the potentiodynamic cathodic polarization curves, cathodic current efficiency and throwing index, as well as the electrical conductivity of these baths. The optimum conditions for producing sound and satisfactory nickel deposits were: NiSO4·6H2O 350 g/L, NiCl2·6H2O 45 g/L and Na3C6H5O7 30 g/L at pH=4 and 55 ℃. The surface morphology of the as-plated Ni deposit was examined by SEM. The results reveal that the nickel deposition obtained from the optimum conditions are composed of compact, non-porous fine grains covering the entire surface. X-ray analysis shows that nickel deposits obtained from the citrate bath have a fine crystal structure compared with deposits from the Watts bath.展开更多
Ni?Co3O4 composite coatings were electrodeposited on mild steel surface from a Watts-type bath in the presence of sodium lauryl sulfate(SLS).The dispersed Co3O4 particles in the presence of SLS have a greater tendency...Ni?Co3O4 composite coatings were electrodeposited on mild steel surface from a Watts-type bath in the presence of sodium lauryl sulfate(SLS).The dispersed Co3O4 particles in the presence of SLS have a greater tendency to move towards cathode and get incorporated in the coating.SLS modifies chemical composition,surface morphology and microstructure of the Ni?Co3O4 composite coating.The developed composite coating exhibits higher corrosion resistance and microhardness than the pure nickel coating.The loadings of bath solution with different concentrations of Co3O4 particles in the presence of SLS provide hydrophobic nature to the coating surface,which is much effective in enhancing the corrosion resistance of Ni?Co3O4 composite coating.The agglomeration of Co3O4 particles(>3 g/L)under high bath load condition develops defects and dislocation on the coating surface,which results in lower corrosion resistance of the deposit.The mechanical properties of the hydrophobic coatings were assessed by the linear abrasion test.展开更多
文摘采用动电位扫描、扫描电子显微镜和X-射线衍射分析分别研究了不同质量浓度的糖精和1,4-丁炔二醇对镍电沉积层的极化作用、表面形貌及晶体取向的影响。结果表明:在瓦特镀镍液中加入糖精和1,4-丁炔二醇,极化曲线均向负电位方向移动。糖精质量浓度增加至2.0 g/L时,极化曲线不再向负电位方向移动,镀层呈现(200)面择优取向。当1,4-丁炔二醇质量浓度增加到0.5 g/L时,其显著提高了镍电沉积过电位230 m V,有效增大成核密度,其镀层微观形貌平整均匀,择优取向并未发生改变。
基金Project(2007CB613607) supported by the National Basic Research Program of China
文摘A new type of electroplating bath suitable for nickel electrodeposition was developed. Trisodium citrate was used as a complexing agent and a buffer in the bath. The buffering capacity between trisodium citrate and boric acid were compared. The effects were investigated under different conditions of bath composition, current density, pH and temperature on the potentiodynamic cathodic polarization curves, cathodic current efficiency and throwing index, as well as the electrical conductivity of these baths. The optimum conditions for producing sound and satisfactory nickel deposits were: NiSO4·6H2O 350 g/L, NiCl2·6H2O 45 g/L and Na3C6H5O7 30 g/L at pH=4 and 55 ℃. The surface morphology of the as-plated Ni deposit was examined by SEM. The results reveal that the nickel deposition obtained from the optimum conditions are composed of compact, non-porous fine grains covering the entire surface. X-ray analysis shows that nickel deposits obtained from the citrate bath have a fine crystal structure compared with deposits from the Watts bath.
基金UGC, New Delhi, India, for the award of Post-Doctoral Fellowship to K.O.Nayana(Award No: F.15-1/2015-16/PDFWM-2015-17KAR-31527(SA-Ⅱ))
文摘Ni?Co3O4 composite coatings were electrodeposited on mild steel surface from a Watts-type bath in the presence of sodium lauryl sulfate(SLS).The dispersed Co3O4 particles in the presence of SLS have a greater tendency to move towards cathode and get incorporated in the coating.SLS modifies chemical composition,surface morphology and microstructure of the Ni?Co3O4 composite coating.The developed composite coating exhibits higher corrosion resistance and microhardness than the pure nickel coating.The loadings of bath solution with different concentrations of Co3O4 particles in the presence of SLS provide hydrophobic nature to the coating surface,which is much effective in enhancing the corrosion resistance of Ni?Co3O4 composite coating.The agglomeration of Co3O4 particles(>3 g/L)under high bath load condition develops defects and dislocation on the coating surface,which results in lower corrosion resistance of the deposit.The mechanical properties of the hydrophobic coatings were assessed by the linear abrasion test.
