Influence of Laser Power on Microstructure and Properties of Al-Si+Y[sub.2]O[sub.3] Coating

Al-Si/7.5 wt.%Y[sub.2] O[sub.3] coatings were prepared on Mg alloy with laser cladding to enhance the wear and corrosion resistance of substrate. The influence of laser power on the microstructure and properties of the coating were discussed. The results uncovered that the coatings consisted primarily of Mg[sub.2] Si, Mg[sub.17] Al[sub.12] , Mg[sub.2] Al[sub.3] , Al[sub.4] MgY, and α-Mg phases. Through calculation, it was observed that the crystal size decreased with the decrease in the laser power. Y[sub.2] O[sub.3] gave the coating a better strengthening effect due to the fine-grain strengthening and hard-phase strengthening. The average hardness of the coating with laser power of 1100 W achieved 312 HV, which was approximately 4.2 times that of the substrate. The wear volume of the coating was 22.2% that of the substrate. Compared with Mg alloy, the self-corrosion potential of the coating increased by 1.09 V, and the self-corrosion current density decreased by three orders of magnitude.