Laser Assisted Cold Spray Technology

       As early as in the late 1990s, shortly after the emergence of low-pressure cold spraying technology, people began to carry out research on laser-assisted spraying technology, but at that time, it was mainly a two-step process, that is, the spray coating was obtained first, and then the coating was subjected to laser treatment. Remelting modification treatment. In recent years, with the development of cold spray equipment, a synchronous processing method has appeared, as shown in Figure 2-39. Among them, the spot size of the laser beam focused on the substrate is the same as the shape and size of the spray spot. In the process of processing, or the workpiece is stationary, the laser spot and the spray spot have been overlapping and kept moving synchronously, or the workpiece is moving, and the two spots keep overlapping, so as to achieve synchronous processing.



The purpose of introducing laser irradiation into the cold spraying process is to heat and soften the sprayed particles, the substrate or both through the laser energy, instantly adjust and improve the mechanical properties of the material and the collision deposition state, and improve the low-pressure cold spray coating. Thickness, deposition efficiency, compactness and bonding strength, thereby improving the performance of the coating; at the same time, the selection range of coating and substrate materials can be wider, the use of gas heating devices can be eliminated, and the expensive helium can be replaced by cheap nitrogen. gas as the working gas. In addition, since the heating degree of the material can be adjusted by measuring and changing the power of the laser spot, etc., the heating temperature of the material can be precisely controlled, so it is even possible to realize the direct forming of the workpiece. Due to the heating effect of the laser on the material, the working gas pressure and heating temperature in the cold spraying process can be reduced, and the preparation of difficult-to-deposit material coatings can also be realized. Using laser cold spraying system to prepare titanium coating, compared with the cold spraying system, the coating deposition efficiency is significantly improved, and the coating porosity is reduced, which can efficiently prepare thick titanium coating, and cold spray forming to prepare parts.