The change in mechanical properties of electrodeposited iron widely depends upon the temperature of heat treatment as well as the conditions of electrodeposition. Mechanical properties of electrodeposited metals exposed at high temperatures are practically important matter owing to the progress of electro-plating for industrial use. Electrodeposited iron is brittle when deposited, but it can be improved by heating.
This paper reports the changes in mechanical properties (such as hardness, tensile strength, elongation, and reduction of area) treated at several temperatures of 200-900°C.
In addition, X-ray diffraction, microphotographs, and other phenomena during tension tests were studied for theoretical consideration. The consideration was mainly explained by dislocation theory.
As the results, it was known that electrodeposited iron which had been heated at 200-190°C, showed excellent mechanical properties over a wide range. The relation between elongation of electro-deposited iron having strong internal stress and heating temperature was indicated by the characteristic curve. When the iron was heated at 900°C, grain size of crystals was rather small.
As the change in elongation and reduction of area depended upon many complicated factors during tension, the above changes in properties cannot theoretically be explained in the present stage.

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In electroplating on the surface of buffed cold rolled steel sheet in stannous sulfate bath, the effects of alkali cleaning or acid pickling of the steel sheet on electroplated tin nuclei were investigated.
When the steel sheet was cathodically cleaned in 70g/l of sodium hydroxide solution at 1amp./dm² for 20sec. or at 5amp./dm² for 1sec., the number of nuclei deposited was about 4 times as many as that of no cleaning. On the other hand, when anodically cleaned, the number gradually decreased with the increase of treating time.
When the steel sheet was subjected to acid pickling in 7% sulfuric acid solution, there were observed undeposited parts after the operation of electroplating. When the sheet was anodically pickled for 20sec., its surface was etched and number of nuclei greatly decreased.

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Effects of pH, temperature, and composition of two different caustic alkaline electroless cobalt plating baths on magnetic properties of deposited films were investigated and the following results were obtained.
(1) The films deposited from caustic alkaline electroless plating solution had the maximum flux density (B_s) of about 10, 000 gauss. The remanent flux density (B_r) varied in the range of 2, 000-7, 000 gauss and the coercive force (H_c) varied in the range of a few -800 oersted, according to plating conditions.
(2) In general, tartrate bath gave a film with high coercivity, while citrate bath had a tendency to deposit a film with low coercivity.
(3) The characteristics of these baths were discussed about the behavior of cobalt-complex in the baths.
(4) The effects of plating conditions on magnetic properties of the films were not the same in both baths, but they could be explained on the characteristics of each bath and the theory of ferromagnetic fine grains.

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The diffusion couples consisting of α Fe and α Fe₃Si were prepared by siliconizing of low silicon steel. The couples were annealed at 1130-1230°C and chemical diffusion coefficients in the range of 3.6 wt. (7.0at.)-11.7wt. (21at.)% of silicon concentration were calculated by Matano's Method. Indentation by Micro Vickers hardness tester was employed as a marking of interface. Partial diffusion coefficients were calculated from the movement of the marking by means of Darken's Relations.
The minimum value of chemical diffusion coefficients at a definite temperature was found at about 10at.% of Si. Both of activation energy and frequency factor gave maximum values at about 15at.% of Si. The chemical diffusion coefficient at 7at.% of Si was in good agreement with the result of Batz. Concentration of silicon at the interface was nearly constant. The dependence of the partial diffusion coefficients on temperature at the interface concentration was represented by the following formulas:
D_Fe=5.6exp(-54×10³/RT)
D_Si=2.2exp(-50×10³/RT)
It was confirmed by the above formulas that D_Si was about two times larger than D_Fe.

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