Tungsten plating has long been considered difficult and of no practical use. Recently, however, the tungsten plating using fluoride bath enabled the deposited film to have so good metallic luster and to be so thick at any plating temperature of wide range that it has become to be used practically.
The compositions of fluoride plating bath and the plating temperatures are as follows:-
1. For 60g/l of tungsten trioxide, the appropriate amount of potassium fluoride is 30-40g/l. If smaller is the quantity than the above, the deposition is poor and tint color becames black. If larger is thequantity than the above, the deposition is deteriorated having various color.
2. The good result will be obtained by adding sodium hydroxide by 60g/l for to 60g/l of tungsten trioxide. In any case, larger or smaller quantity of the sodium hydroxide than the above is not favourable, and will decrease the deposition.
3. The plating temperature should be higher than 60°C, and the higher the better. In the case of lower temperature, the deposition will not be satisfactory and not hard enough for practical use.

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In bright quenching of steel into oil, the ability whether steel surface can be quenched as bright state or not is named brightness of oil. In this report, the relation between the brightness and the process of oxidation and polymerization of oil by Indiana Method are examined. The brightness increases in the induction period of oxidation and polymerization process of oil, and decreases in the peroxide formation period down to the minimum at the end of this period. Then, it recovers slightly in the peroxide decomposition period, and after that decreases more and more rapidly in the later stage of the peroxide decomposition period and in the polymerization period, because of sludge formation or viscosity increase. In mineral oil of which viscosity increase is slight, the brightness does not decrease in the polymerization period, if sludge in oil is taken away.

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Various methods of pretreatment of aluminum plates were investigated. As a result, the α-Al₂O₃ formed by anodic oxidation was better than the alumina by chemical treatment.
As reported in the first paper, the sample coated with the film by anodic oxidation in the mono or mixed dilute sodium perborate, sodium metasilicate, pottasium borate and lithium borate solution, followed by borosilicate system frit application were satisfactory. However, the effect of the mixed solutions on adhesivity was greater than that of the mono solution.
In the present study such treatments as the above were applied to lead enamel and phosphate enamel with the satisfactory result.
In the pretreatment of lead and phosphate frits, aluminum plates treated with mixed aqueous solution of sodium metasilicate (water glass), sodium perborate, lithium borate and sodium phosphate showed better adhesiveness than those treated with mono aqueous solution of these salt components.
The results may be summarized as follows:
1. In the bending test of lead system enamel, sodium metasilicate, sodium perborate and lithium borate were the most satisfactory compounds in the tests carried out in ternary mixture aqueous solution.
Lithium borate was most satisfactory of the three kinds of mono component aqueous solution.
In the thermal shock test, adhesion was not different in all mono component aqueous solutions.
2. In the bending test of phosphate system enamel, sodium phosphate was most satisfactory of the mono component aqueous solutions.
In the thermal shock test, adhension of phosphate enamel was not different from that of lead enamel in all mono component aqueous solutions. But ternary mixture solution gave satisfactory results.
Thus samples submitted to anode treatment in mixed solutions were superior in every respect to those treated in mono component solution.

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In aluminum-diffusion coating with Fe-AI powder as diffuser, the powder has marked effects on the characteristics of coating. The present work deals with the studies on (1) packing of Fe-Al powder, (2) its aging, and (3) its fineness, by a laboratory method following after the practical operation.
The results are as follows: (1) If a degree of packing of the powder is in the range of 2.0 -3.0g/cc, little effect is seen on coating properties. (2) When the same powder is used repeating more than 5 times, the diffusion is reduced, and the powders of approximately 60 mesh are decreased. (3) As for fineness rather coarse powder of about 60 mesh is most effective. (4) It is difficult to produce the powder of uniform fineness, hence it is preferable to provide the powder of suitable distribution of fineness in which the amount of 60 mesh powder is maximum.

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