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
Nanocrystalline cobalt coatings were produced from cobalt sulfate based electrolytes by using pulse current electrodeposition technique.The effects of bath composition and electrodeposition condition on current effici...Nanocrystalline cobalt coatings were produced from cobalt sulfate based electrolytes by using pulse current electrodeposition technique.The effects of bath composition and electrodeposition condition on current efficiency,morphology,structure and hardness of the coatings were investigated and the optimum deposition condition was determined.It was found that increment of cobalt sulfate concentration and sodium dodecyl sulfate(SDS)concentration in the bath had a negligible effect on microhardness of the coatings,while they were effective on electrodeposition current efficiency.Adding saccharin to electrodeposition bath decreased crystallite size of hexagonal close-packed(hcp)cobalt films and increased their microhardness without significant effect on current efficiency.Smoother and less defective coatings were also obtained from baths containing SDS and saccharin.The results revealed that both the current efficiency and microhardness were changed by variation of peak current density and duty cycle.Besides change of smooth morphology of the coatings to needle-shaped one,crystallite sizes and preferred orientation also varied with increasing the current density and duty cycle.展开更多
The use of more and more electron products requires interior wood products to have the performance of electromagnetic shielding. One of the ways to realize it is to introduce the chemical plating which has already bee...The use of more and more electron products requires interior wood products to have the performance of electromagnetic shielding. One of the ways to realize it is to introduce the chemical plating which has already been developed in electron industry into wood processing. The paper clarifies the mechanism of electroless copper and gold plating and its application to wood. It emphasizes the development and technology of electroless copper and gold plating on wood. Meanwhile, it points out that it is highly feasible to take this technology into effect.展开更多
文摘目前国内对碱性锌酸盐体系电镀锌钴合金的研究较少。研究了碱性锌酸盐Zn-Co合金电镀体系中合金镀液组成及工艺条件对镀层Co含量的影响,得到了最佳镀液组成及工艺条件:锌钴离子总浓度0.3 mol/L,锌钴离子摩尔比9∶1,150 g/L氢氧化钠,15.0 m L/L添加剂A,1.0 m L/L添加剂B,电流密度Jc3 A/dm2,温度25~30℃。在最佳工艺条件下可得到Co含量为2.0%~2.2%的Zn-Co合金镀层。结果表明:Zn-Co金的沉积表现为异常共沉积;在一定范围内,镀层中钴含量的变化会影响镀层光亮度的变化;钴配位剂对Zn-Co合金的共沉积电化学行为不造成影响。
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.
文摘Nanocrystalline cobalt coatings were produced from cobalt sulfate based electrolytes by using pulse current electrodeposition technique.The effects of bath composition and electrodeposition condition on current efficiency,morphology,structure and hardness of the coatings were investigated and the optimum deposition condition was determined.It was found that increment of cobalt sulfate concentration and sodium dodecyl sulfate(SDS)concentration in the bath had a negligible effect on microhardness of the coatings,while they were effective on electrodeposition current efficiency.Adding saccharin to electrodeposition bath decreased crystallite size of hexagonal close-packed(hcp)cobalt films and increased their microhardness without significant effect on current efficiency.Smoother and less defective coatings were also obtained from baths containing SDS and saccharin.The results revealed that both the current efficiency and microhardness were changed by variation of peak current density and duty cycle.Besides change of smooth morphology of the coatings to needle-shaped one,crystallite sizes and preferred orientation also varied with increasing the current density and duty cycle.
文摘The use of more and more electron products requires interior wood products to have the performance of electromagnetic shielding. One of the ways to realize it is to introduce the chemical plating which has already been developed in electron industry into wood processing. The paper clarifies the mechanism of electroless copper and gold plating and its application to wood. It emphasizes the development and technology of electroless copper and gold plating on wood. Meanwhile, it points out that it is highly feasible to take this technology into effect.
