ZHAO Yun-cai,SHANGGUAN Xu-chao,ZHANG Ji-wu,HE Wen.Microstructure and Wear Resistance of WC/Fe Plasma Sprayed Coatings Modified by Laser Remelting[J],47(3):20-27 |
Microstructure and Wear Resistance of WC/Fe Plasma Sprayed Coatings Modified by Laser Remelting |
Received:August 01, 2017 Revised:March 20, 2018 |
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DOI:10.16490/j.cnki.issn.1001-3660.2018.03.004 |
KeyWord:plasma spraying WC/Fe ceramic coating laser remelting dispersion strengthening wear resistance wear mechanism |
Author | Institution |
ZHAO Yun-cai |
School of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology, Ganzhou , China |
SHANGGUAN Xu-chao |
School of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology, Ganzhou , China |
ZHANG Ji-wu |
School of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology, Ganzhou , China |
HE Wen |
School of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology, Ganzhou , China |
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Abstract: |
The work aims to improve microstructure of plasma sprayed WC/Fe composite ceramic coating and improve corresponding wear resistance, and study wear resistance of laser remelted coating at different temperature. The plasma sprayed WC/Fe composite ceramic coating was treated by adopting laser remelting technique. Microstructure characteristic, phase composition and microhardness of the plasma sprayed coating before and after laser remelting was tested and characterized with scanning electron microscope (SEM), X-ray diffractometer (XRD) and microhardness tester, respectively. Wear resistance of the laser remelted coating was compared and investigated at 25 ℃, 200 ℃ and 400 ℃ with a friction and wear tester. Plasma sprayed WC/Fe composite ceramic coating exhibited layered structure. After laser remelting, defects such as lamellar structure and pores nearly disappeared, top structures in laser cladding zone were isometric crystals and fine dendrites. Bottom structures in the zone were afterbirth-like crystals, and structures in coating-substrate binding zone were coarse dendrites, and the coating had metallurgical bonding with the substrate. Dispersion strengthening effect of high hardness compounds such as WC, W2C, M23C6 and Ni6BSi2 in the laser remelted coating made microhardness of the laser remelted coating increase by nearly 1 time than that of the original plasma sprayed coating. Worn sub-surface of the laser remelted coating was the most intact at 25 ℃, and micro-cracks appeared at 400 ℃. Remelting can eliminate various defects of plasma sprayed coating to form dense coating. The remelted coating exhibits different wear mechanisms at different temperature and the best wear resistance at 25 ℃. |
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