The Coating on Iron and Steel with Titanium Tetrachloride

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%.