Effect of laser treatment on electroless-plated NI-P-SiC composite coatings

The effect of laser treatment on Ni-P-SiC composite coatings produced by electroless-plating was investigated. The surface morphology, microscopic structure, ingredient and harness of the composite coatings were synthetically analyzed with scanning electron microscope, energy distribution spectrometer, X-ray diffraction and micro-hardness tester. It was observed that the crystalloblastic transformation would occur in the Ni-P-SiC composite coatings upon laser treating. The X-ray diffraction confirmed that the coating contains Ni and Ni3P crystals, but no SiC characteristic peaks detected with all coatings. It was also found that a new type of phase Ni2Si would emerge in the coatings with increasing of laser power. This new phase, which has been little reported in previous references, exhibited an obvious diffraction peak. The micro-hardness measurement results showed that when the laser power set at 400w with scanning speed at 1.51n / min, the hardness of the coating was higher than that obtained by conventional furnace heating, and the reason for the higher hardness was discussed in this paper.