Abstract: TiC4 composite ceramic coatings with different CeO2 contents were deposited on 45# carbon steel substrate by laser-cladding. The cladding coatings were examined and tested for microstructural features, chemical compositions, phase structure, microhardness by scanning electron microscope (SEM), X-ray diffraction (XRD) analysis and micro-hardness tester separately. TiC4 particles phase and surrounding TiC4 particles rim phase was found by SEM, XRD. Experimental results showed the addition of CeO2 improved the dispersion of TiC4 grain and prevented the TiC4 particle from bridging. At 2.0 wt.% CeO2, the TiC4 grains shows best dispersion, and the micro-hardness of the coating reached 1100 MPa. With excessive CeO2, the TiC4 grains became bridging, the pattern of particles submit long strip, and the cladding layer’s micro-hardness decreased slightly. Dry friction tests showed the addition of CeO2 improved the tribological properties. The wear mechanism of cladding coating without dopping was servere adhension and scuffing, while that of the CeO2 dopped coating was dominated by mild abrasive wear. Dopping CeO2 had no obvious improvement on the wear resistance of the coating.
Key words: laser cladding, ceramic coating, surface modification, rare earths
Author: CHENG Xiyun, Engineering College, Shantou University, Shantou 515063, China
E-mail: xycheng@stu.edu.cn
Tribology, Vol. 30, Issue 3, 2010, 250~255
