ANALYSIS OF (CR,MO) OXYCARBIDE FILMS GROWN ON STAINLESS-STEEL VIA METALLOORGANIC CHEMICAL-VAPOR-DEPOSITION

A mixture of hexacarbonyl of chromium and molybdenum ((Cr,Mo)(CO)(6)) was used to deposit oxycarbide films an stainless steel at temperature s of 175 degrees-450 degrees C, Through the analysis of deposition kin etics in various temperature regions, the controlling mechanism was de termined to be exothermic surface reactions, Activation energies of th e low- and medium-temperature regions were determined to be 71.2 and - 60.1 kJ/mol, respectively. Some properties- including densities, compo sition, and crystalline phases- of the films were investigated, Result s revealed that the chromium content of coating products increased as the temperature increased, The dominating surface reactions switched a s temperature increased, because of the increase of chromium content i n the precursor gas. Hence, the coating rate and density increased to a maximum, then decreased as the coating temperature was increased to >275 degrees C, Deposited phases were determined by X-ray diffractomet ry, and the relationship with film density phases has been discussed, using their microstructural textures from scanning electron microscopy micrographs, Corrosion resistance was measured by an electrochemical method, The films obtained in the low- and medium-temperature regions improved the corrosion resistance of stainless-steel substrates by a f actor of 24, In addition, the latter case showed the effect of passive protection and was an optimized selection for corrosive protection, T he relationship of the improvement of corrosion resistance, physical p roperties, and the contribution of composed phases was discussed.