The wettability of the sprayed layer alloy to the surface of the workpiece mainly depends on which factors

       The wettability of the spray coating alloy to the workpiece surface mainly depends on the following factors:



    (1) The influence of the coating alloy and the metal composition of the workpiece. When the coating alloy and the workpiece metal do not interact in liquid and solid state, the wettability between them is very poor; if the coating alloy and the workpiece metal can dissolve and diffuse each other, the molten coating alloy can be better Wet the workpiece surface. When a passive film is easily formed on the surface of the substrate, it is difficult for the molten coating alloy to wet the surface. The composition and properties of the passivation film are determined by the composition of the substrate. For example, when nickel-based alloy is sprayed and melted, it is difficult to wet the chromium plating layer and carburized layer; the wettability is average on heat-resistant steel; the wettability is good on ordinary carbon steel and alloy structural steel; on pure iron Wetting is good. If you encounter a workpiece with poor wettability, you can try to spray a thin layer of pure iron on the surface that needs to be spray-melted, which can greatly improve the wettability and improve the quality of the spray-melt layer.

    (2) The cleanliness of the workpiece surface. The cleaner the surface of the workpiece, the better the wettability.

    (3) The roughness and wettability of the working surface is better than that of the smooth surface. This is because the crisscross grooves on the rough surface play a special capillary action, which is conducive to the flow of molten alloy along the surface of the workpiece and improves the wettability.

    (4) Remelting temperature. The increase of the remelting temperature reduces the surface tension of the molten coating alloy, which leads to the easy spreading of the liquid coating alloy, thereby improving the wettability of the molten coating alloy to the workpiece surface. However, the remelting temperature should not be too high. If it is too high, the fluidity of the coating alloy will be too large, causing flow and making the melt spray layer not smooth and uniform. If the temperature is too high, the molten coating alloy will aggravate the erosion of the surface of the workpiece and change the performance of the melt spray layer. Therefore, the remelting temperature should be properly controlled.