Five ml/l of the reaction product obtained from ethylenediamine and epichlorohydrin was added as a brightener to the zincate bath composed of ZnO (10g/l) and NaOH (100g/l).
Bright zinc plating from this bath had similar appearance, range of current density for brightening, and throwing power to those of the deposit from cyanide bright zinc plating bath. However, the current efficincy was slightly lower and the hardness was higher as compared with the deposit from the cyanide bath. Accordingly, the ductily of the former deposit seemed to be inferior to that of the latter.

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Etching mechanisms of ABS and polypropylene resins (used for metallizing) were studied by means of infra-red spectra and gas chromatography.
The results of experiments were as follows.
1) When ABS resin was etched with high concentrated mixture of sulfuric and chromic acids, only butadiene particles were preferentially oxidized and dissolved into the etching reagent to form a long chained saturated hydrocarbon. On the contrary, when it was etched with the above mixture of low concentration, AS matrix as well as butadiene was attacked and dissolved into the reagent to form benzoic acid. Under the both conditions of etching, polar groups were formed on the surface layer of the resin.
2) When polypropylene was etched with the same mixture, the surface layer was oxidized to form polar groups and dissolved into the reagent to form long chained hydrocarbons having CHO and COOH groups.

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These studies were performed on the formation of chelates by the reaction between cupric ion and amino acids such as glycine (G), imino-diacetic acid (IMDA), and nitro-triacetic acid (NTA). In addition, the effect of pH on structures and solubilities of these chelates in water, and the electroplating of copper in these solutions of chelates were also studied.
The following results were obtained.
1) Owing to low stability of [CuG]⁺ and slight solubility of [CuG₂]⁰, the range of pH for obtaining good deposit of copper was narrow in the solution of Cu-G chelates.
2) Good deposit of copper could not be obtained from the solution of Cu-NTA chelate [Cu(NTA)]^-, owing to its very high stability.
3) Stable [Cu(IMDA)₂]^2- was formed by the reaction between cupric ion and IMDA in the pH range of 6.0-12.0. Adherent and lustrous deposit of copper on steel was obtained under the following condition.
CuSO₄·5H₂O 0.125mol/l Temperature 20-70°C
IMDA 0.313mol/l Cathodic current density 0.2-1.0amp./dm²
Na₃AsO₃ 0.4g/l Agitation needed
pH 6.0-11.5
The current efficiency of 80-100% was obtained under the above condition.

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After-etching of semi-conductor P-N junction element is a very important process for carrying out proper action of transistor or diode upon the device, in which indium pellet is alloyed with single crystal germanium pellet.
In the alloying process, there were produced thermal stress, crystal imperfections, irregularity, and some contaminations on the boundary and around the periphery of P-N junction at the alloying temperature. These imperfections produced low inversed voltages, V_CBO and V_EBO; made increase or drift of saturation currents, I_CBO and I_EBO; made larger noise figure with low gain; made smaller amplication factor; and made the life shorter for instability in electric action.
The techniques for removing these imperfections prevailed hitherto are as follows.
(1) Electrochemical etching
(2) Chemical etching
(3) Supersonic etching
(4) Electron beam or ion spattering
The above techniques (3) and (4) were suitable for the mass production of germanium type transistor (1-10MHz class) and the studies of these techniques have been pursued as follows.
(A) Alkaline electrolytic etching
(B) Alkaline electrolytic etching combined with acid chemical etching
(C) Acid chemical etching
The above item (C) showed the best result in electric characteristics and stabilization for accelerated life test.
This paper reports the results of experiments on alkaline electrolytic etching for 10MHz class transistor and its after-treatment.
The optimum condition for the element was as follows.
Electrolyte……KOH 30%aq. solution
Current density……DC 60mA. per one element
Etching time……3s. x 4 pulses
The author got high value of V_CBO at low value of rbb' but the average value of V_EBO was much lower than V_CBO. In the testing of I_CBO and I_EBO by diode curve tracer, leakage currellt of several μA was often found out in some specimens before the avalanche break down.
The latter half of this paper describes the acid chemical etching performed after the electrolytic etching. K⁺ ion adsorbed around the periphery of P-N junction was removed and the junction element, slightly etched by acid Chemical etching, was researched by the behavior of V_EBO. The Composition of the after-acid etching. solution and the specification for the etching were as follows.
Pure water……6vol.
H₂O₂……2vol. (30% reagent)
HF……1vol. (49% reagent)
Etching temperature……room temperature
Etching time……5-20s.
As the results of experiments, the increase of V_EBO and the decrease of surface leakage current were confirmed.

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The authors investigated the relationship between the magnetic properties and crystal structures or compositions of Co-Ni and Co-Ni-P plating films chemically deposited from 4 kinds of the baths reported in the previous papers.
The results obtained were summarized as follows.
1) In general, maximum flux density, remanent flux density, squareness, and coercive force of the films were decreased with the increase of nickel content in the films. However, the decreasing tendency was different among the types of baths, from which the films were deposited.
2) The film deposited had higher squareness and smoother surface when the plating bath was more stable. The decreasing order of baths for depositing films of high squareness was arranged as follows:
A-C-9>C-C-7>A-T-9>hydrazine.
3) The structures of films deposited from different types of baths were different one another, even though they had the same alloy composition. It can be explained by the differences in metallic ions in the baths (stability and reactivity of complexes) and phophorus contents of the films.
4) The films composed of fine crystal grains were deposited from the bath of high stability (containing highly sequestered metallic ions). The size of these grains is related with the magnetic properties of the films.

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This paper discusses on the effect of welding conditions on wear phenomena of low manganese deposited steels and on the effect of heat treatment on the improvement of wear resistance of the deposited steel.
The results showed that the wear mechanism and the curve representing the relation between sliding velocity and wear characteristics were nearly identical with those results obtained by low carbon deposited steels.
However, the relation between the number of deposited layers and the wear showed that the wear loss was likely to be decreased with the increase in the number of layers, depending upon the behavior of alloying elements.
Moreover, the treatment of quenching or tempering after the welding was very effective in improving wear resistance of the deposited metal. In particular, the tempering at 200°C after quenching was the most suitable condition of heat treatment for the decrease of wear loss.

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