The corrosion resistance of the 99.7% aluminized steel, galvanized steel, 18 Cr stainless steel and Chromium, Nickel, Cupper, Brass or Zinc electroplated steel was examined for 2 years in the seaside, rural, and industrial districts.
As a result aluminized steel showed as good corrosion resistance as that of pure aluminium in each district. Especially anodized aluminized steel had especially the bright surface.

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Conductmetric method in testing of soft film type rust preventive oil used as temporary coating to protect metal surface against corrosion and its standardization as testing method was studied. In this test “temperature-cancelled-out electrical resistance specimens” were used. Namely, the specimen is made from a couple of copper ribbons (21cm×3mm×0.05mm), one of them being coated and protected by rust preventive oils, while the other bare and exposed to corrode. The couple was immersed in a glass bottle, in which 1N-HCI aqua solution was poured, and after 48-72 hours, the electrical resistance of each ribbons were measured by a double bridge. The difference of each resistance is one of the measurements of rust preventability of the test oil.
One of the principal advantages of this method is that it enables the operator to make measurements while corrosion is proceeding without interrupting the test and without making separate temperature or calculations.

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Mild steel surface was roughened with various kinds of acid. Nickel and cobalt were deposited on the steel by chemical nickel plating and anodic oxidation treatment (A. C.).
Ordinary white enamel was applied directly on the steel and the adhesion of the enamel was examined by bending and tension test. (1) In the cases of nickel and cobalt deposited on the mild steel plate by metal surface treat-ment, the rougher the surface of the mild steel the better is the adhesion of the enamel. (2) With the same surface roughness, the adhesion of enamel on the surface by anodic oxidation in cobalt salt and boric solution was better than that by chemical nickel plating. (3) The enamel on the surface pickeld with 20% NHO₃ and then treated by anodic oxidation in cobalt salt and boric acid solution shows the same good adhesion as the conventional double coat enamal.

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Characeristic properties of the alkaline nickel plating bath containing nickel-triethamolamine complex under various conditions have been studied.
As to the configuration of this complex, six-dentate structure shown in Fig 5 has been proposed.
To the electrolyte, NiCl₂ 6H₂O and H₃BO₃ were added for the purpose of increasing nickel anode corrosion and regulating pH value. Bright deposit was obtained at room temperature with current density of 2A/dm², whereby the cathode current efficiency was 50-60%.
The potential polarization curve obtained by plotting cathode potentials against current density at 25°C, showed abrupt change at about 3.5A/dm² to more basic side. This point of flexure corresponded to the highest limit of current density allowable to give a satisfactory deposition.
Further studies would be required to elucidate the plating mechanism from this bath.

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Recently, the color of gold alloy plating tends to be preferred red and pink, and the thick deposit with greater wear resistance is required. But the said properties depend upon bath component, operating condition and metallographic properties of deposited alloy. Bath component varies, depending, for instance, upon the decrease of metal ion concentration, increase of free cyanide concentration, etc. It is, therefore, impossible to keep the composition of deposited alloy constant regardless of the proper starting operating conditions.
The author studied the bath component and operating condition which affect the composition, color, hardness, and other properties of the deposited alloy, and investigated proper conditions of practical operation.
The bath component and operating condition are as follows:
Gold as potassium gold cyanide 1g/l Free cyanide as potassium cyanide 4-8g/l
Copper as cuprous cyanide 12-20g/l Disodium phosphate 30g/l
Nickel as potassium nickel cyanide 30-50g/l Current density 2-6A/dm²
Temperature 25°C Without agitation
The results are as follows: (1) Increase in free cyanide concentration tends to increase gold content in deposited alloy, while increase in current density tends to decrease the alloy gold content. (2) The deposited copper contend varies with current density, inversely with free cyanide concentration, and is not affected by cuprous ion concentration in plating solution. (3) Nickel content in alloy tends to be constant roughly, the range being 2 to 8%, under various conditions, such as nickel ion and free cyanide concentration and current density. (4) The hardness of deposited alloy in the said bath reaches 200 Vickars. (5) The thickness of the deposit per unit time is not affected by current density, while it decreases with an increase of free cyanide concentration.

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