Journal of the Metal Finishing Society of Japan

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Chromium-molybdenum alloy electrodeposits were obtained from the Sargent's chromium plating bath, to which molybdenum salt had been added, under the similar plating conditions to those of the Sargent bath with no addition of the salt. Chromium-molybdenum alloy deposits (containing more than 3% of molybdenum) of about 50μ in thickness gave hardness of Hv 1, 000-1, 300, which was higher than that of the conventional hard chromium plating, and their abrasion resistance was also 2-3 times as high as that of the latter.
The relation between the molybdenum content of these deposits and the hardness or the amount of abrasion could be expressed by the following equations, respectively.
Hardness (Hv)=95.8x+715
Amount of abrasion (mg)=-3.8x+33.3
where x=Molybdenum content of the deposits (%)
As shown in the above equations, the hardness increased about 100Hv and the amount of abrasion decreased about 4mg with the increase in 1% of molybdenum content in the deposits.

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The effects of substrate temperature during the flame spraying, addition amount of Nd₂O₃ to BaTiO₃, and heat treatment on the structure of the semi-conductive coatings were investigated by means of X-ray diffraction, X-ray microanalyzer, thermal analyzer, and electron microphotography.
As the results, the difference in the effect of substrate temperature was found between with and without the additive. When the additive was not used, the crystal growth was accelerated and the glassy material content was reduced with the rise in the substrate temperature. On the contrary, when the additive was used, the crystal growth was retarded and the glassy material content was increased with the rise in the temperature.
There was a close relationship between PTC (Positive Temperature Coefficient) and crystal size or amount of glassy material.

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