Showing papers in "Journal of The Surface Finishing Society of Japan in 1968"
TL;DR: In this article, the relation between plating conditions and rate of deposition or composition of plated film was investigated in two kinds of ammoniacal alkaline electroless plating baths (A-T and A-C) for cobalt-nickel alloys of sulfate-hypophosphite system.
Abstract: The relation between plating conditions and rate of deposition or composition of plated film was investigated in two kinds of ammoniacal alkaline electroless plating baths (A-T and A-C) for cobalt-nickel alloys of sulfate-hypophosphite system.The results obtained were as follows.(1) The preferable conditions for stable baths having relatively high rate of deposition and giving good appearance of plated film were as follows:Ammoniacal alkaline tartrate bath (A-T) Ammoniacal alkaline citrate bath (A-C)CoSO4+NiSO4 0.1mol/l 0.1mol/lNaH2PO2 0.2mol/l 0.2mol/lNa-citrate - 0.2mol/lNa-tartrate 0.5mol/l -(NH4)2SO4 0.5mol/l 0.5mol/lpH(NH4OH) 9.0 9.0Operating temperature 90°C 90°C(2) Under the above conditions, a desired film composition having any ratio of nickel to cobalt and containing some amount of phosphorus was obtained at a relatively high rate of deposition by controlling the ratio of concentrations of ions between nickel and cobalt in each bath.(3) The plating rate in A-T was higher than that in A-C, but the former gave inferior appearance of deposited film to the latter owing to its lower stability. The plating rates in the both baths were higher than those in single baths (for cobalt or nickel plating) under the same conditions.(4) The utilization efficiencies of hypophosphite in the above baths were usually kept in the range of 20-40% in A-T, and 28-30% in A-C, both of which were higher than that of nickel plating baths and lower than that of cobalt plating baths under the same plating conditions.(5) The phosphorus content in the plated film almost linearly decreased from 2.4 to 1.9% in A-T or from 5.8 to 1.8% in A-C with the increase of cobalt content in the film.
2 citations
TL;DR: In this article, the corrosion resistances of electroless nickel plating films, having different phosphorus contents from plating baths of the same compositions (but of different pH values), were measured by a few sorts of electrochemical methods and dissolution tests in solutions of IN-H2SO4, 5%-NaCl, and IN-NaOH.
Abstract: Phosphorus contents of nickel plating films obtained from electroless nickel plating baths containing various kinds of organic salts were determined.Corrosion resistances of electroless nickel plating films, having different phosphorus contents from plating baths of the same compositions (but of different pH values), were measured by a few sorts of electrochemical methods and dissolution tests in solutions of IN-H2SO4, 5%-NaCl, and IN-NaOH.As the results, the corrosion resistances of the plating films increased with the increase of phosphorus contents, but passivity effects were not found in each film containing phosphorus.
2 citations
TL;DR: In this article, the effects of composition and pH of electroless cobalt plating bath on the structure of cobalt films were studied mainly by X-ray diffraction method.
Abstract: Effects of composition and pH of electroless cobalt plating bath on structure of cobalt plating films were studied mainly by X-ray diffraction method. Cobalt deposits of electroless plating had polycrystalline structure of α-cobalt with close packed hexagonal lattices, and the grain size and orientation of the crystals greatly depended upon the composition and pH of the plating bath. Deposits of finer grain size were obtained, when the growth of crystals was inhibited by adsorbed hypophosphite ions or reduced phosphorus atoms adsorbed on the surface. As the formation and diffusion velocities of cobalt atoms on the crystal plane controlled preferred orientation of cobalt crystals, the deposits with fiber structure were produced.
1 citations