Microstructures and High-Temperature Friction–Wear Performance of Laser-Remelted WC-12Co Coatings by HVOF

ABSTRACT

A WC-12Co coating prepared by high-velocity oxygen fuel (HVOF) was remelted with a CO₂ laser, and the surface–interface morphologies, plane energy spectrum, and phases of the coating were analyzed by means of field emission scanning electron microscopy (FESEM), energy-dispersive spectrometry (EDS), and X-ray diffraction (XRD), respectively. The friction and wear behaviors of the WC-12Co coating were investigated at high temperature with a wear test, and the morphologies and the changes in chemical elements on the wear scar after the wear test were analyzed with SEM and EDS, respectively. In addition, the influence of high temperature on the coefficient of friction (COF) and wear performance is discussed. The results show that the substrate is closely bonded with the substrate after laser remelting (LR), which includes mechanical bonding accompanied by metallurgical bonding. The average coefficient of friction (COF) at 600, 700, and 800°C is 0.6832, 0.3957, and 0.1922, respectively. The wear mechanisms of WC-12Co coating at 600 and 700°C are adhesive wear, abrasive wear, and oxidative wear, respectively, and the wear mechanism of the coating at 800°C is serious oxidative wear.

KEYWORDS:

• Laser remelting
• high-velocity oxygen fuel
• WC-12Co coating
• coefficient of friction
• wear mechanism

Funding

Financial support for this research by the Jiangsu Province Science and Technology Support Program (Industry) (BE2014818) is gratefully acknowledged.