Laser alloying on chromium-coated surface of nodular cast iron

Laser-alloying technique was used to modify the mechanical properties of the chromium-coated surface of nodular cast iron. It was shown that the laser-modifying layer consists of tiny eutectic ledeburite, chromium carbide Cr7C3 and (CrFe)(7)C-3, which can strengthen the wear resistance, by scanning electron microscopy(SEM), X-ray diffraction(XRD) and energy dispersive spectrometry (EDS). The crystallized area and the bright white layer area coexist in the modified layer. The microhardness of the bright white layer area of modified layer reaches HV 927(or HRC 68), while that of the matrix is HV 221.