W. Chaoqun, Guangzhou Research Institute of Non-ferrous Metals, Guangzhou, China
Aimed at the characteristic of copper with good conducted heat, high cooling rate and big coefficient of expand, the compound coating of Ni-base self-fluxing alloy (NiCrWB+50%Al2O3)and WC(WC-12%Co) alloy was sprayed on a copper substrate by High Velocity Air Fuel(HVAF). The Ni-based coating was analyzed by means of Optic microscopy, Scanning electron microscopy (SEM), Electron probe microanalysis (EPMA) and X-ray diffraction (XRD) respectively. The results indicated that the structure of coating was composed of melted particles and partly unmelted round particles, WC distributing in lamellar. A few of Al2O3 particles remained in the coating. The phases in the coating were consisted of γ-Ni, WC and a little Ni3B. The amorphous structures appeared and no Al2O3 phase existed. The adhesion intensity between coating and copper substrate was above 50MPa. The coating was obtained good heat fatigue capability. Test result showed that the Ni-WC coating had a better erosion resistance than which coating with no WC particles.
Aimed at the characteristic of copper with good conducted heat, high cooling rate and big expansion coefficient, the compound coating of Ni-base self-fluxing alloy (NiCrWB+50%Al2O3)and WC(WC-12%Co) alloy was sprayed on a copper substrate by High Velocity Air Fuel(HVAF). The Ni-based compound coating was analyzed by means of Optic microscopy, Scanning electron microscopy (SEM), Electron probe microanalysis (EPMA) and X-ray diffraction (XRD) respectively. The results indicated that the structure of coating was composed of melted particles and partly unmelted round particles, WC distributing in lamellar. A few of Al2O3 particles remained in the coating. The phases in the coating were consisted of ã-Ni, WC and a little Ni3B. The amorphous structures appeared and no Al2O3 phase existed. The adhesion intensity between coating and copper substrate was above 50MPa. Wear result showed that the Ni-base compound coating had a better erosion resistance than which coating with no WC particles.
