The electrodeposition of tin-nickel alloys from acidic baths containing stannous and nickel chlorides, was investigated in relation to the effects of several addition agents on the appearance and composition of the deposits as well as on the cathode current efficiency. Synergistic use of a combinations of thiourea and either cresol sulfonic acid or 1, 5-sodium naphthalenedisulfonate as addition agents above 65°C produced the best alloy deposit with respect to brightness. The cathode current efficiency and the tin content of the deposit, however, decreased with decreasing the current density below 1A/dm². A bright and adherent Sn-Ni alloy coating was obtained at 65°C and above 1A/dm² with a high current efficiency, from the bath containing 30g/l SnCl₂⋅2H₂O, 300g/l NiCl₂⋅6H₂O, 132g/l NaCl, 10 vol% HCl and the addition agents as mentioned above; the atomic ratio of Sn to Ni of the alloy was kept to be 1 to 1.

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The oxidation behavior of Ta sheets, calorized at 1000°C for 16hr, has been examined in flowing air (1L/min) over the temperature range from 900 to 1300°C. At 1100°C, the weight gain was only 0.45mg/cm² with no further change in weight and was found to be a minimum comparing with those at other testing temperatures. This seems to be attributable to the fact that a double oxide (TaAlO₄) is formed sufficiently to prevent further oxidation at this temperature. At 900°C, the alloy layer was mostly oxidized into oxides (Ta₂O₅ and Al₂O₃), whereas, at 1000°C, the inner part of the alloy layer remained unoxidized, but the alloy changed into lower aluminides (TaAl and Ta₂Al), and TaAlO₄ as well as Ta₂O₅ were found in the scale. At high temperature such as 1300°C, all of the alloy layer changed into Ta₂Al compound. Only a small part of aluminum in the TaAl₃ alloy penetrated into the Ta substrate during oxidation at lower temperatures, while almost all aluminum was oxidized into Al₂O₃ oxide. At higher temperatures than 1100°C aluminum penetrated more easily, forming voids in the alloy layer, but some of aluminum in the alloy changed, at first into Al₂O₃ oxide in the scale. This oxide still prevents the oxidation, but the accumulation of such voids in the alloy layer will result in a sudden breakaway.

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The removal of zinc ions (Zn²⁺) from Watts type bath by a weak basic resin (Sumichelate CR-2) was studied by using batchwise and column methods. The zinc ions adsorbed on the resin are desorbed by sulfuric acid solution (2N). Zinc ions are adsorbed on the resin in the nickel chloride solution, but not in the nickel sulfate or the boric acid solution. The adsorption is influenced by the concentration of nickel chloride or sulfuric acid in the bath. The amount of Zn²⁺ ions adsorbed on the resin from the bath is represented by Freundlich's adsorption isotherm.

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The purpose of this study is to obtain integrally colored oxide film on aluminum in sulfuric acid bath, where the coloring is found to be closely related to the thermal process of metal itself and to the pre-treatment of the anodizing process. Under the appropriate conditions of aging and desmutting treatment, from white grey to black colored oxide film was formed. The formation of colored oxide film was attributed to the precipitation of β′ Mg₂Si phase and the color was independent of the size of the precipitation. The dark color tone was remarkable with increasing time and temperature of the desmutting treatment in sulfuric or nitric acid solution.

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99.99% Al specimens were anodized in 10% H₂SO₄ and 2% H₂C₂O₄⋅2H₂O solutions at 20, 30, and 40°C by applying a constant current, i_a, in the range 0.5-100mA/cm². The anode potential, E_a, and the dissolution current of oxide, i_d, were measured during anodization. The porosity, α, and the thickness, h, of the formed oxide were measured as functions of current and temperature. Plots of E_a against logi_a were always S-shaped curves which tend to shift to lower potential region with increasing temperature. It was found for fixed anodic charge that (dissolution rate) and α decrease with increasing current and decreasing temperature. The decreases in i_d/i_a and α are always accompanied by an increase in the total film-thickness, h. Transport numbers for Al³⁺ and O^2- ions in the barrier layer, T_Al³⁺ and T_O^2-, were calculated on the assumptions that Al³⁺ ions move into the solution without forming oxide at the barrier layer/solution interface and that part of the oxide produced at the barrier layer/metal interface, due to O^2- migration, dissolves into the solution to form a porous layer. The figure obtained for T_Al³⁺ was in the range 0.25-0.40 and it was found to increase with decreasing current and rising temperature.

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