日本金属学会誌

J. Japan Inst. Metals, Vol. 21, No. 10 (1957),
pp. 599-602

Titanium Coating (2nd Report). Titanium Coating by Fused-Salt Electrolysis

Yoshiki Ogawa, Yoshihiro Hisamatsu, Kazutaka Kawamura and Junji Tatsuma


Abstract:

In this paper another method of preparing a protective titanium coating on mild steel has been dealt with. The procedure consists of electrolyzing potassium titanium fluoride dissolved in potassium and sodium chloride under an inert, i.e. argon atmosphere. Electrolytic cell is made of a graphite crucible with a diameter of 8 cm and a depth of 20 cm, of which the outer surface is protected by 18-8 stainless steel casing from atmospheric oxidation. Better titanium coatings were obtained by using modulated current (D.C.partially interrupted at the rate of 3 times a second) than in the case of plain D.C.
Consistently good results were obtained under following condition:

Concentration of K2 TiF6 about 16 wt%
Temperature 900°
Cathodic current density of direct current. 350~650 A/dm2
of modulated current. Upper C.D. 350~650 A/dm2
Lower C.D. 130~250 A/dm2
The coating has been found to be softer than in the case of pyrosol method, the microvickers hardness being ca. 300. Salt spray tests have shown a corrosion resistivity of the coating as high as in the case of the pyrosol method.


(Received 1957/6/22)

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