Development and Characterization of a Laser Clad WC Reinforced Ni-Cu Alloy Composite Coating on Brass
A-R. Yan, Y-J. Li and Z-Y. Wang
Using a high power diode laser (HPDL) to deposit a cermet composite coating of Cu-WC-Ni on brass substrate in order to increase surface abrasion resistance whilst maintaining good electrical conductivity. The microstructure of the coating was studied by using an optical microscope, a scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. The hardness, abrasion resistance and conductivity was studied by using a microhardness tester, sliding friction pin-disk tester and a resister tester, respectively. It is concluded that the phases of the Cu-WCNi composite coating constitute WC and W2C grains; α-Cu, β-Cu, γ-Cu dendritic crystals and intermetallic compounds of Cr4Ni15W, WC and W2C are evenly distributed in the coating. With the increase in WC content the dendritic crystal microstructure is refined, average hardness and abrasion resistance increase accordingly when the mass fraction of WC reaches 25%, the average hardness of the coating is four-times the base metal, abrasion loss is decreased to 1/19 that of the base metal, and the conductivity is as before.
Keywords: High power diode laser (HPDL), brass, WC, Ni-Cu alloy, laser cladding, composite coating, wear, abrasion resistance, electrical conductivity