Since ductile cast iron was invented, cast iron has been used for various purposes. However, because of its poor corrosion resistance, the use of cast iron in corrosive environments was restricted. As pre-viously reported, the authors succeeded in obtaining a prominent protective film on steel by silicon impregnation (so-called siliconizing).
In the present work, 3 kinds of specimens, i.e. nodular cast irons having ferrite and pearlite matrix, respectively, and gray cast iron, were siliconized by means of a mixed gas of silicon tetrachloride and oxygen free argon in accordance with the silicon impregnation of steel. The results obtained were summarized as follows.
(1) Microscopic examination showed that porous films were formed on nodular cast iron with ferrite matrix, and particularly, on gray cast iron. On the contrary, when nodular cast iron with pearlite matrix was siliconized at a relatively high temperature for a short time, the film obtained had comparatively less pores in number.
(2) Immersion tests of the siliconized cast irons in dilute sulfuric acid showed that the siliconized film protected the underlying cast iron core from the attack of acid though it was porous. Above all, the film which had been formed on nodular cast iron with pearlite matrix by siliconizing at a high temperature for a short time showed the best corrosion resistance.

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The structures of electrodeposited Au-Ni alloys were studied by means of X-ray diffraction, hardness test, and electron microscopic examination.
The lattice constants of the deposits obtained from the baths, in which pH was adjusted to 10.5, were found to decrease proportionally to the increase of Ni content. The maximum Ni content of the deposits reached 5% by weight and a solid solution with Au was produced. Microhardness of the deposited layer was 150Hv.
On the other hand, the deposits from actidified baths (pH3.0) had Ni content of more than 12% by the increase of the ratio of Ni/Au. However, it was suggested that the deposits having only 5% of Ni content formed a solid solution. The deposited layer consisted of fine crystals and showed hardness of as high as 180Hv.

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The relationship between coating structure and dielectric properties was investigated by means of X-ray diffraction method and measurementof temperature characteristics between -55 and 160°C.
Flame-sprayed coatings essentially consist of a crystalline component and a glassy component as reported in the previous paper. Their dielectric properties largely depended upon the content of glassy material. The large content of the glassy material was always followed by low axial ratio of c/a so that the both effects made the dielectric constant low.
When BaTiO₃ of small particle size (about 1 micron) was sprayed the dielectric constant of the deposited coating would be low, owing to the low heat capacity of small particles.
A small portion of crystalline BaTiO₃ contained in the coatings was still kept in tetragonal system even above 155°C.
The coefficient of linear expansion of flame-sprayed coatings almost agreed with that of the cubic phase of ceramic BaTiO₃ in the measured range of between room temperature and 1204°C.
Activation energy of the flame-sprayed BaTiO₃ calculated from the slope of resistivity-temperature curve considerably differed from that of ceramic BaTiO₃ in the lower temperature region.
Direct observation of very thin films of the sprayed coatings revealed that the coatings contained a rather large amount of extremely small crystallites (20-30Å) The electron diffraction pattern agreed well with the X-ray diffraction pattern.

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The authors investigated the effects of heat treatments on hardness of Co-Ni and Co-Ni-P plating films chemically deposited from 4 kinds of alloy baths reported in the previous papers.
The following results were obtained.
1) The films as deposited from a hydrazine bath exhibited the hardness of 400-500Hv, and the hardness of Co-Ni alloys was higher than that of each single Co or Ni film. The hardness of these films was secarcely changed when they were heated to a certain temperature up to 400°C in nitrogen atmosphere.
2) The hardness of films deposited from hypophosphite baths was slightly higher than that of the above (deposited from a hydrazine bath) films. However, its value was remarkably increased by the heat treatments up to 500°C, owing to the precipitation of metallic phosphide.
3) The treating temperature for giving the maximum hardness of films was found to be 400°C for Ni-P films and it shifted to the higher temperature side with the increase of cobalt content in the film.

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In the present work, there are pursued operating conditions of Taber Abrasion Tester to evaluate the wear resistance of anodic oxide films on aluminum.
It was observed that the abrasive wheel siutable for this experiment was resilient type CS-17, and all the wheels of resilient type were composed of α-Al₂O₃ by X-ray diffraction method. The applied load of 1, 000g was essential to measure the weight loss by abrasion. When a specimen was abraded through 2, 000 turns of the wheel before the main measuring, the refacing was not necessary during the test. However, when the specimen was replaced with a new one, the refacing was necessary to remove the effect of clogging of foreign particles on the wheel. The weight loss of each specimen was evaluated after 15, 000 turns.
In the next stage, the wear resistance of anodic oxide films on aluminum was tested with Taber Abrasion Tester by keeping the conditions of operation mentioned above.
Each specimen in the above test was anodized under the following conditions:
Electrolyte composition sulfuric acid 100g/l
and oxalic acid 15g/l
Electrolysis time 45min.
Current density 1, 2, 4, 6, and 8amp./dm²
Bath temperature -5, 0, 5, 10, and 20°C
The results of these tests were as follows. The anodic oxide films formed at a lower bath temperature and under a higher current density proved to have higher wear resistance as expected. The change in current density had little effects on the wear resistance at a lower temperature.

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It was confirmed that adherent film of polymer was formed onto steel electrodes by electrolysis of organic compounds under suitable conditions.
Steel plate was usually used for both of anode and cathode; sometimes, carbon was used for anode. Ionization of iron was observed when steel was used for anode. Unsaturated carboxylic acids, aldehydes, trioxane, and vinyl compounds were used as monomers. The electrolysis was carried out under a constant current or under a constant applied voltage. This paper reports the weight and thickness of the film and its stability in water. The stability of the film in water especially depends upon the kind of supporting electrolytes. The coulomb efficiency for film formation and the quality of film depends upon the kinds of solvents and supporting electrolytes. The merits of this process consist in the direct formation of adherent polymer films for coating the cathode plate from monomers.

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For the purpose of determining the optimum temperature and relating factors for vapor deposition of zirconium carbide, the deposition rates were measured with a thermo-balance.
Deposition was observed at emperatures above 770°C and the (100) planes were developed in parallel with the surface of graphite substrate. The both planes of (110) and (100) were found relatively distinct at above 840 and 1200°C, respectively. The deposition took place within 0.4 sec. after the two reacting gas streams were mixed together. The deposition rates were proportional to the linear velocity of hydrogen and the concentrations of zirconium tetrachloride and hydrocarbons. The increase of the rates with temperature became slower at higher temperatures owing to the pyrolysis of hydrocarbons.
Higher rates were given by paraffins and naphthenes. However, the highest rates were found in the range of their concentrations of 0.3-0.7vol.% (indicated as reduced value to propane); and the rates were rather decreased by carbon deposition beyond that range.
Benzene was out of the above regularity, owing to its large anti-pyrolytic property. Its growth rate was 0.3-0.8μ/min. under the optimum condition at 1200-1300°C.

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