The formation of whisker was observed during the electrolytic polymerization of acrylonitrile onto metal surface in the presence of styrene or benzene. It was found by X-ray analysis that the whisker was amorphous and some specific absorptions were evident in the region of lower wavelength of its IR spectrum. The molecular weight of polymer, or the component of the whisker, was about 1, 000.

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In the previous paper, the authors reported the effects of various plating conditions on nickel-tungsten deposits from Rochelle salt bath.
This paper reports the effects of those conditions on the deposits from citrate bath.
The following results were obtained.
(1) The amount of tungsten deposited was larger when the concentration of sodium tungstate wes higher, current density was lower, and temperature was higher. On the contrary, the amount of nickel deposited was less under the above conditions.
(2) Better plating conditions were obtained when the bath, containing sodium fluoride and ammonium fluoride, was heat-treated at 50°C for 24h.
(3) The amount of alloys deposited was the largest from the bath containing sodium fluoride and was the least from the bath containing ammonium fluoride.

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Spectrophotometric and polarimetric measurements were made on Ni-W complexing agent systems.
Citric and tungstic acids formed a very stable complex ion at the molar ratio of 1:1. Complex of tartaric acid was also formed at the same ratio as above, but it was less stable than that of citric acid, because it was changeable by heating or aging.
Complex ions of nickel with citric or tartaric acid were formed at pH=5.0. However, they were less stable than those of tungstic acid and were decomposed on addition of tungstate solution.
On addition of sodium fluoride to the above systems, the values of spectral transmittance were changed in only the system of containing tungstate. It suggested the formation of tungsten complex, in which fluorine is co-ordinated as ligand atoms.

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The characteristics of bright zinc pyrophoshate bath was investigated. Some addition agents (for ex., aldehyde, molybdate, etc.) were used for obtaining bright deposits. The relationship between brightness and cathodic polarization was studied.
The optimum conditions were summarized as follows.
Bath composition:
Zinc pyrophosphate 30g/l Potassium hydroxid 5g/l
Potassium pyrophosphate 346g/l Addition agents 1-2g/l
P₂O₇/Zn (Weight rativ) 17.2 (Zn 12.5g/l) pH 10.0-10.5
Operating conditions:
Temperature 55°C
Cathode current density 1-3amp./dm²
The structure of the depsit obtained from bright zinc pyrosphosphate bath was examined by X-ray diffraction. The deposit had crystal orientations on (100) and (110) faces. The results obtained by X-ray diffraction were discussed by comparison with those by electron microscopy. The throwing power and the cathode current efficiency were measured under various conditions. The deposit showed high throwing power and the current efficiency of above 95%.
It was found that the bright zinc pyrophosphate bath gave much more advantages as compared with other conventional cyanide baths.

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Phosphorus content, grain size, and hardness of the deposits from the following electroless bath were measured for various conditions of pH and concentrations of hypophosphite and ethylene diamine.
NiSO₄·7H₂O 0.1mol/l pH 6
NaH₂PO₂·H₂O 0.2mol/l Temperature 90±1°C
H₂NCH₂CH₂NH₂ 0.15mol/l
The following results were obtained.
(1) Crystalline deposits having preferred orientation of (111) were obtained from acid plating solutions (pH=6) having low concentration of sodium hypophosphite.
(2) The deposition rate at pH=6-7 was found to increase with the increase of concentration of sodium phosphate or ethylene diamine.
(3) The grain size was smaller when the phoshorus content was higher since the growth of grains was inhibited by phosphorus adsorbed on lattice plane.
(4) Change of hardness did not always correspond with the change of phosphorus content. Accordingly, the hardness of deposits would not merely depend upon phoshorus content.

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Study was mape on electrodeposition of zinc from zinc gluconate bath. The bath was prepared from zinc sulfate and sodium gluconate. Equilibrium potential and catholic polarization were examined for the compositions of the above bath. X-ray diffraction was also carried out on the zinc deposits obtained under various conditions.
Linear relationship was found between the equilibrium potential and pH of the zinc gluconate solution, when pH value was at above 7. However, the equilibrium potential showed nearly constant values at pH of less than 7.
Cathodic polarization of zinc electrode in gluconate bath increased with the increase of pH in the range of 5-9.
In general, cathodic polarization of zinc in gluconate bath was found to be much less than that in conventional cyanide baths.
Activation overvoltage was estimated by the interrupter method and transfer coefficient α in the electrode reaction of zinc deposition was found to be 0.738.
X-ray diffraction revealed that the matte deposit obtained from zinc gluconate bath had no preferred orientation of crystal. However, the bright deposit obtained from the same bath containing an addition agent such as Cyanamer P-26 had distinct preferred orientation of (110).

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