An accurate quantitative method for NdFeB magnetism based on laser-induced breakdown spectroscopy

Abstract

NdFeB magnetic materials are widely used in daily life, such as in permanent magnet motors, loudspeakers and computer disks. The NdFeB magnetic material has excellent magnetic properties, and its magnetic properties are also the key to judge the production quality of NdFeB. Therefore, the precise quantification of the magnetic properties of NdFeB magnetic materials is crucial. Laser induced breakdown spectroscopy (LIBS) is a technique to obtain the spectrum of chemical elements by excitation of plasma on the surface of a sample with a high energy laser. In this paper, a precise classification and magnetic quantification method for NdFeB magnetic materials based on laser-induced breakdown spectroscopy is designed, which is different from the traditional direct magnetic property detection method and uses element detection to quantitatively analyze the magnetic properties indirectly. A laser-induced breakdown spectroscopy system was used to collect the characteristic spectrum of NdFeB magnetic materials, and the sliding window minimum removal base method was independently designed to further optimize the detection accuracy. A classification model and quantitative analysis method model were further established and optimized. The random forest method was used to preliminarily classify NdFeB magnetic materials, and the GA-ELM method was used to conduct quantitative analysis of magnetic properties. Quantitative magnetic properties include Br, Hcj, Hcb and (BH)max. The error analysis of the final quantitative analysis is as follows: RMSE of Br reaches 0.0001526, RMSE of Hcj reaches 0.0001937, RMSE of Hcb reaches 0.00197, and RMSE of (BH)max reaches 0.00785. It is verified that the magnetic quantification method for NdFeB magnetic materials based on laser-induced breakdown spectroscopy can effectively conduct accurate quantitative analysis of the magnetic properties of NdFeB magnetic materials and provide a fast, convenient, accurate and economical detection method for the quality control of magnetic materials workshops.