The following results were obtained on the mechanism of the formation of Cu-films, which were precipitated and developed over the Fe face by means of galvanic substitution of Cu salt.
(1) Cu-films consisted of 2 layers; i.e., the one of plate crystals of about 1μin thickness and coherently developed over the Fe face, and the other of spindle-shaped needle crystals of about 1-16μ in length and developed over the plate crystals of Cu.
(2) The primary precipitated Cu-particles contributing to the growth of Cu-films were spheroidal, having diameter of 40-150Å.
(3) The relations on the coherency found between the plate crystals of Cu and Fe face were as follows:
(001)Fe||(001)Cu [110]Fe||[100]Cu}(1) (101)Fe||(101)Cu [010]Fe||[101]Cu}(2) (111)Fe||(111)Cu [121]Fe||[011]Cu}(3)
(4) As Fe face having high index was easily ionized in the solution of Cu salt, the face was corroded and some of the faces of {110} Fe, {100} Fe, and {111} Fe remained. Thus, the face remained was substituted by Cu atoms according to one of the relations on coherency.
(5) The Cu-films were easily stripped off from the Fe face by means of dipping them in the solution of Cu for 3min. These facts were explained by that Fe atoms combined with Cu atoms were ionized and transferred through the defects of plate crystals of Cu.

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The relation between the plating conditions and the rate of deposition or the composition of plated film on electroless plating bath for cobalt-nickel alloy of sulfate-hypophosphite system was investigated. The results obtained were as follows.
1) The following 3 kinds of baths were selected for stable plating baths having relatively high rate of deposition.
a) Caustic alkaline citrate bath (C-C)
b) Ammoniacal alkaline citrate bath (A-C)
c) Ammoniacal alkaline tartrate bath (A-T)
2) The preferable conditions for plating bath of C-C type were as follows: CoSO₄+NiSO₄ 0.1 mol/l, Na-citrate 0.2mol/l, H₃BO₃ 0.5mol/l, pH=7(NaOH), and operating temperature 90°C.
Under the above conditions, a desired film composition containing phosphorus with any ratio of nickel to cobalt was obtained by controlling the ratio of concentrations of nickel to cobalt in the bath.
3) The phosphorus content in the alloy film decreased almost linearly from 14% (in nickel film) to 4% (in cobalt film) with the increase of cobalt content in the film.
4) The sum of the rate of deposition in each single bath was almost equal to the rate of the alloy plating bath; however, the ratio of nickel to cobalt in the alloy film did not correspond well with the rate of deposition in each single bath, but a higher content of cobalt than the value calculated from its rate of deposition was always given.

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A novel process for Al coating was investigated to give more decorative appearance and corrosion resistance to sheet steel.
The process consisted of sprinkling atomized Al powder over the surface of sheet steel treated with adhesives, drying the adhesives, compacting the powder into a solid layer by rolling, and sintering the solid Al layer and bonding it with steel by heat treatment in an electric furnace.
A viscous aqueous solution of polymetaphosphate was used as the adhesives in the concentration of 0.5-1.5g/l.
It was most important to stick Al powder evenly onto the steel surface. This process was attained by adding a small amount of organic compounds such as fatty acids or amines to Al powder. When the addition amount of organic compounds to Al powder increased, the amount of Al powder stuck to the steel decreased. The even adhesion was effectively obtained by the addition of 5×10^-4m mol/g of organic compounds.
Sintering was performed by heating at 500-700°C for 10s-3h. Although the properties of Al coated steel depend upon its coating conditions, it has many attractive properties such as good appearance, excellent corrosion resistance, and superior reflective power for light.

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The coating of titanium on iron specimen was performed in a furnace, into which titanium tetrachloride was introduced with hydrogen or argon as an carrier gas. The temperature of the furnace was at 1000-1200°C and the reaction was continued for 60-150min. The concentration of TiCl₄ in the mixed gas was lower than 10%.
In any conditions of treatment, hydrogen was more effective than argon. The fact indicated that the reduction of titanium tetrachloride by hydrogen would be one of the main reactions in the coating process. It was also found that the coating was accelerated by the presence of pure titanium around the specimen.
The composition of coating layer was determined by chemical analysis and X-ray diffraction. The outermost layer of the specimen treated in hydrogen containing 5% of TiCl₄ (temperature in the furnace was 1200°C and the reaction was continued for 150min.) was TiFe₂, and the content of titanium in that layer was about 30%.

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For the purpose of investigating the diffusion behavior of chromium, nickel, and molybdenum into iron during the sintering of iron powder, metallic cementation was carried out concurrently with the sintering by heating the pre-compressed iron powder which had been embedded in chromium, nickel, or molybdenum powder. A microscope and an X-ray probe microanalyzer were used to observe and analyze the diffusion layer. The results showed that the depth of diffusion layer increased with the rise in sintering temperature or with the decrease in pre-compressed pressure on the powder, and the thickness of diffused layer increased linearly with the increase of treating time. The results of additional tests showed that chromium and nickel were simultaneously diffused into iron when the pre-compressed iron powder was embedded in a mixed powder containing chromium and nickel at a proper ratio. The diffusion coefficient of chromium was evaluated in the process of simultaneous sintering and metallic cementation.

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