Microstructure, Corrosive-Wear and Electrochemical Properties of TiC Reinforced Fe30 Coatings by Laser Cladding

Ceramic phases played the positive role in the friction process of alloy coatings, which improved the corrosive-wear and electrochemical properties. In this study, Fe30-xTiC coatings were prepared on 45 steel using laser cladding, and the microstructure, phase and hardness of obtained coatings were analyzed using a super-depth field microscope, x-ray diffraction and microhardness tester, respectively. The effects of TiC mass fraction on the corrosive-wear and electrochemical properties of Fe30 coating were investigated with the corrosive-wear and electrochemical tests, and the enhancement effect of TiC in the Fe30-xTiC coating was also discussed. The results show that the Fe30-xTiC coatings are composed of TiC, Ni-Cr-Fe, Fe, FeNi FeCr and Cr7C3 phases, and their microstructure is changed from petaloid to dendrite by the addition of TiC, in which the grain boundary is decreased, and the grains become compact. The average coefficients of friction of Fe30-5%TiC, -10%TiC and -15%TiC coatings are 0.551, 0.419 and 0.366, respectively, and the corresponding wear rates are 486, 323 and 263 mu m3 s-1 N-1, respectively, and the wear mechanism is combined of adhesive wear, corrosion wear and abrasive wear. Moreover, the polarization resistance of Fe30-0%TiC, -5%TiC, -10%TiC and -15%TiC coatings is 1.34 x 104, 3.18 x 104, 3.26 x 104 and 8.57 x 104 Omega cm2, respectively, and the corresponding charge transfer resistance is 1.73 x 103, 2.34 x 103, 2.17 x 104 and 1.49 x 105 Omega cm-2, respectively, showing that the Fe30-15%TiC coating has the best electrochemical corrosion resistance.