Mechanism And Experimental Study On Pulsed Laser Cleaning Of NdFeB Magnetic Material

With the rapid development of high-tech industries today,as an important functional material,NdFeB is widely used in the field of defense and military industry and other emerging fields with its excellent magnetic properties.Due to the loose and porous structure of the NdFeB magnetic material,a large amount of dirt will be adsorbed on the surface during processing,while the potential of the neodymium-rich phase in the NdFeB material is extremely low,which easily causes oxidative corrosion between the crystals,resulting in the failure of subsequent electroplating process,which does not protect the surface of the NdFeB material,which greatly affects the performance and surface quality and restricts the application of the NdFeB magnetic material.The traditional cleaning method has some shortcomings,such as serious pollution,material damage and incomplete cleaning.In view of the above problems,this paper presents a technical scheme of cleaning and processing NdFeB magnetic materials with pulsed laser,and carries out experimental research,the main research contents are as follows:1.Based on the surface characteristics of magnetic materials,the corrosion mechanism of NdFeB magnetic materials is analyzed,the adhesion model of surface pollutants and substrates is constructed through the adsorption mechanism between pollutants and substrates;the cleaning mechanism was analyzed,and the laser cleaning conditions for removing pollutants by laser were obtained.2.Use numerical simulation to simulate the temperature field during the laser cleaning process,and analyze the influence of different parameters on the laser cleaning temperature field distribution and cleaning depth.The simulation results show that the temperature of the surface of the material is inversely proportional to the scanning speed and proportional to the laser energy density.A smaller scanning speed and a larger laser energy density both increase the removal amount of material and the cleaning depth.Finally,the laser Scanning speed of1200 mm/s and laser energy density of 15.28 J/cm~2 will not damage the substrate material.3.The pulsed laser was used to clean the NdFeB magnetic material,and the influences of laser energy density,laser spot overlap rate and scan track overlap rate on the cleaning effect were investigated.The results show that too large or too small laser energy density will lead to greater cleaning surface roughness and poor cleaning quality,When the laser spot overlap rate and scan track overlap rate are 40%,and the laser energy density is 15.28 J/cm~2,the cleaning quality is the best,which is consistent with the simulation results.