Effects of Al2O3 Addition on the Microstructure and Properties of CoCr Alloys

In typical Cobalt-chromium (CoCr) alloys powders, aluminum oxide (Al2O3) powder can be added. In the present study, we successfully prepared alloyed samples of various powder ratios by laser cladding, and analyzed their microstructure and carbide structural characteristics, including microhardness, biological properties, morphology (using scanning electron microscopy), and crystal structure (using X-ray powder diffraction). Elemental distribution was also determined by energy-dispersive X-ray spectral analysis. The results showed that Al2O3 addition caused the alloy to change from slender columnar crystals to columnar grains similar, to equiaxed grains. In addition, Al2O3 agglomeration zones appeared, and carbide structures were altered. The mechanism of the observed performance changes was also analyzed.