Showing papers in "Journal of The Surface Finishing Society of Japan in 1971"
TL;DR: In this paper, the authors described the studies on addition agents to the copper-zinc alloy plating baths for satisfying the conditions of uniform color tone, high brightness, and thick plating layer.
Abstract: The conditions necessary for decoration in bright copper-zinc alloy plating are uniform color tone, high brightness, and thick plating layer. This paper describes the studies on addition agents to the copper-zinc alloy plating baths for satisfying these conditions.Addition agents to cyanide plating baths were divided into the following two groups, according to their actions. One was a group of brighteners giving brightening action and the other was a group of color controllers giving uniform color tone. It was found that As and Se belong to the former and ammonia and amines belong to the latter.Color controllers were not found in these addition agents to the alkali plating baths complexed by tartrates. However, it was found that brightening action was given by the complexing action of amines and sulfamic acid salts in the presence of a small amount of cyanides.Bright thick platings were obtained by the addition of an adequate amount of these addition agents to each of the baths.
4 citations
TL;DR: In this article, a bath containing a mixture of silver cyanide and stannous pyrophosphate was prepared for studying improvement in anti-tarnish property of Ag alloy deposits and the bath compositions and electroplating conditions for obtaining the deposits having about 10% of tin content and the properties of the deposits were examined.
Abstract: The baths containing a mixture of silver cyanide and stannous pyrophosphate were prepared for studying improvement in anti-tarnish property of Ag alloy deposits. The bath compositions and electroplating conditions for obtaining the deposits having about 10% of tin content and the properties of the deposits were examined.The results obtained were as follows:(1) A bright Ag alloy deposit (80-95% Ag) was obtained with stirring from a bath containing free K4P2O7 75-150g/l, free KCN 15-25g/l, Sn2+7-15g/l, Ag+8-16g/l and H2O2 (30%) 1-3ml/l by electrolysis under cathodic current density of 0.3-1.0Amp./dm2.(2) The bath became turbid and precipitate was formed with the lapse of time. However the process could be retarded to some extent by addition of a small amount of H2O2.(3) As compared with single Ag deposit, Ag-Sn alloy deposits had higher hardness and lower anti-tarnish property.
3 citations
TL;DR: In this paper, the displacement of the Kα peak of aluminum was calculated by the following equation:Δλ=λ(aluminum metal)-λ(anodic oxide coating of aluminum)
Abstract: In the preceding report, the authors discussed the co-ordination numbers of aluminum and sulfur in anodic oxide coatings of aluminum, which had been prepared from sulfo-salicylic acid or sulfuric acid electrolyte, by fluorescent X-ray method.The results suggested that the aluminum atoms in the anodic oxide coatings consist of both of 4 and 6 ligands.The dispersion in measurements of the co-ordination numbers would be due to the contamination of the test piece with aluminum metal, which had been mixed into the test piece during its folding for preparation.Therefore, this paper reports the results of determination of co-ordination numbers of aluminum atoms in various coatings by means of E.P.M.A, method.The following 8 kinds of electrolytes were used in these experiments:Sulfuric acid (for 2 kinds of test pieces), oxalic acid, chromic acid, sulfo-salicylic acid, p-phenol sulfonic acid, sodium phosphate, and ematal solution.The displacement of the Kα peak of aluminum was calculated by the following equation:Δλ=λ(aluminum metal)-λ(anodic oxide coating of aluminum)The following results were obtained:The co-ordination numbers of aluminum atoms in the anodic oxide coatings prepared from the various electrolytes were considered to be the both of 4 and 6 ligands.The above results quite agreed with those obtained by the fluorescent X-ray method and it was believed that there were no significances among the various kinds of coatings.
2 citations
TL;DR: In this paper, the growth of the dendritic structure was controlled by the following factors: 1. Current density and exchange current density2. Ion concentration3. Ionic conductivity.
Abstract: Electrodeposition of metals (such as Ag, Bi, Cd, Co, Cu, Ni, Pb, Pd, Pt, and Zn) from nonaqueous DMF solutions saturated with the corresponding metal salts was investigated under steady-state current with no agitation.Crystals having regular dendritic structure were formed in cases of Co, Ni, Pb, and Zn under current density of 10-64mAmp/cm2. Whereas, less crystalline or amorphous deposits were obtained in case of Pt.The deposits of Bi, Cd, Cu, and Pd were grown up into dendritic or mossy structure, according to the current density.The growth of the dendritic structure was controlled by the following factors:1. Current density and exchange current density2. Ion concentration3. Ionic conductivityThe leading factors for promoting the growth of dendritic structure in D.M.F. solutions were low exchange current density and low ionic conductivity.
2 citations
TL;DR: In this article, the cathodic polarization characteristics of black chromium plating bath were measured by potentiostatic method for the investigation of their cathodic reactions, and the following results were obtained:
Abstract: The cathodic polarization characteristics of chromium plating baths, to which various anions had been added, were measured by potentiostatic method for the investigation of their cathodic reactions.The following results were obtained:1) The cathodic reaction of black chromium plating bath in the potential range of the 4 th branch consisted of electrodeposition of hydrated chromium oxide film and black chromium plating as seen in pure chromic acid solution.2) Metallic chromium was directly deposited from the stage of chromate film without parsing through the stages of hydrated chromium oxide film and black chromium plating.3) The deposition process and properties of the deposits were varied according to kind and amount of anions added to the chromium plating bath; and also they depended upon the conditions of electrolysis.
2 citations
1 citations
TL;DR: In this paper, surface roughness, hardness test, Erichsen test, conical cup test, and measurement of stationary potential-current curve were investigated by Ni-Al2O3 electro-codeposits on Cu plates.
Abstract: Some properties of Ni-Al2O3 electro-codeposits on Cu plates were investigated by surface roughness, hardness test, Erichsen test, conical cup test, and measurement of stationary potential-current curve. Specimens were obtained from Watt's bath containing 25-150g/l of alumina particles (1, 0.3, and 0.05μ in particle size).The results obtained were summarized as follows.(1) The alumina content in the codeposits was parabolically increased with the increase in concentration of alumina in the plating bath. The rate of increase was lower with the decrease in the particle size of alumina.(2) Every surface of the specimens had no brightness. When the particle size of alumina was 1μ, the surface was rougher with the increase in alumina content. However, when it was 0.3, or 0.05μ, no effect of alumina content was observed.(3) The surface hardness was linearly increased with the increase in alumina content, and also increased with the decrease in its particle size.(4) The forming property was deteriorated after the plating in all specimens, independent of alumina content and particle size.(5) The corrosion resistance of specimens from 3% NaCl solution was decreased with the increase in alumina contents. The similar tendency was observed for every particle of alumina.
1 citations
TL;DR: Corrosion tests and measurements of anodic and cathodic polarization curves of aluminum were conducted in hydrochloric, sulfuric, nitric, and oxalic acids at pH=0 and 1.
Abstract: Corrosion tests and measurements of anodic and cathodic polarization curves of aluminum were conducted in hydrochloric, sulfuric, nitric, and oxalic acids at pH=0 and 1. The results obtained were as follows:1) The values of corrosion rate at pH=0 in the acids used were as follows:In hydrochloric acid 77.1mdd (mg/dm2/day)In nitric acid 24.1mdd (mg/dm2/dayIn sulfuric acid 12.4mdd (mg/dm2/dayIn oxalic acid 6.2mdd (mg/dm2/day2) The values at pH=1 in the acids used were as follows:In hydrochloric acid 11.7mdd (mg/dm2/day)In nitric acid 7.0mdd (mg/dm2/dayIn sulfuric acid 7.0mdd (mg/dm2/dayIn oxalic acid 6.7mdd (mg/dm2/day3) The anodic polarization curve of aluminum in hydrochloric acid showed little polarization. The current was produced at a potential slightly nobler than the spontaneous electrode potential. Pitting corrosion was produced on the electrode.4) Limiting current appeared in the anodic polarization curves in the acids other than hydrochloric acid. It was due to the formation of oxide film on the surface of aluminum.5) Cathodic polarization curves were varied according to the quality of aluminum and kind of acids. The reason would be due to the electronic conductivity of the films on the surface of cathode.6) The corrosion current determined from the intersecting point of Tafel lines of anodic and cathodic polarization curves fairly corresponded with that calculated by the weight loss.