Laser surface alloying of copper with Cr/Ti/CNT for enhancing surface properties

In this study, laser surface alloying of commercially pure copper (cp Cu) with Cr/Ti and Cr/Ti/CNT was conducted using a high-power diode laser. Cu–Ti intermetallic phases were detected in the Cu/Cr matrix of the laser-alloyed specimens without CNT. While TiC was found in the Cu/Cr matrix of the laser-alloyed layers with CNT. Compared to cp Cu (60 ± 10 HV0.2), the laser-alloyed specimens without and with CNT could achieve hardness up to 423 ± 12 HV0.2 and 860 ± 24 HV0.2 respectively. Sliding wear tests were also carried out at 60 km/h in dry condition with a pin-on-disc tribometer. Compared with cp Cu, the wear resistances of all laser-alloyed specimens were significantly improved due to solid solution alloying, existence of harder phases including Cr, Cu–Ti intermetallics and TiC. The wear resistance of the laser-alloyed specimens was increased up to a factor of 1220 times as compared with cp Cu. For the polarization study, the corrosion current densities of all laser-alloyed specimens (0.164–0.275 μA/cm2) in 3.5% NaCl solution at 25 °C were found to be lower than that of copper (3.362 μA/cm2) due to presence of passive Cr and Ti.

Abstract licence: CC BY-NC

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