Sensitivity Analysis for Process Parameters in Mo2FeB2 Ternary Boride Coating by Laser Cladding

The process parameters of laser cladding have a significant influence on the forming quality of the coating. This research investigates the relationship between input process parameters (laser power, scanning speed, pre-placed thickness) and output responses (height, width, dilution rate) of Mo2FeB2 coating through sensitivity analysis. The microstructure and properties of selected coatings were analyzed to discuss the corresponding relations. The results showed that the laser power positively affected the coating width and dilution rate, while negatively affecting the coating height. The scanning speed had a negligible effect on the height and dilution rate. The pre-placed thickness had a positive influence on the height and width; it negatively affected the dilution rate. Based on the sensitivity analysis, the thickness of the pre-placed coating determined the most sensitivity to the height. The sensitivity of the width to laser power was the highest among all parameters. The sensitivity of dilution rate to laser power and pre-placed powder thickness showed a noticeable impact. When the scanning speed was 3 mm/s, the forming quality of coating had a significant sensitivity for a higher or lower laser power (1.5, 2.1 kW) and higher or lower powder thickness (0.8, 1.2 mm). The analysis of microstructure and microhardness of Mo2FeB2 coating indicates that the Mo2FeB2 coating improves substrate properties. The microhardness of the Mo2FeB2 coating was 4–6 times that of the substrate, and the highest microhardness could be obtained by 1.5 kW laser power, 3 mm/s scanning speed, and 1.2 mm powder thickness from the sensitivity analysis results.