Preparation Of Boron-Containing Silicon Steel By Molten Salt Pulse Electrodeposition

To improve the plasticity and magnetic property, Boron was added into silicon steelby electrodeposition and followed diffusion annealing. The diffusion annealing processare mainly studied in this dissertation．Silicon steels with different boron content were produced by pulse electrodepositionin NaCl: KCl: NaF: Na2B4O7=2:2:1:0.04(mole ratio), the parameters were depositiontemperature of850℃, current density of20mA/cm2, duty cycle of20%and the period of1000μs. Annealing temperature was studied by differential thermal analysis and laserconfocal microscope. The effects of annealing temperature and annealing time oncomposition distribution, microstructure, phase, magnetic property and plasticity wereanalyzed by GDS, Zeiss microscope, XRD, ATS-200M iron loss measuring instrumentand Zwick material testing machine. The kinetics process and diffusion rule of boron insubstrate during annealing were analyzed. The texture of substrate, deposited sample anddiffused sample were analyzed. Plasticities of silicon steel with different boron contentswere analyzed.The results showed that the melting temperature of sample of deposition time of20min was about1250℃, the annealing temperature were selected1150℃,1175℃,1200℃,1225℃, and the annealing time were selected for the20min,30min,40min,50min. The diffusion coefficient of boron at1150℃,1175℃,1200℃was138.93μm2/s,161.32μm2/s,178.33μm2/s respectively, the activation energy was about86.49KJ/mol,and the diffusion mechanism of boron in substrate was controlled by interstitial diffusion.The sample with0.0033%boron was produced by annealing. The core loss P1.5andmagnetic induction B50of silicon steel with0.0033%boron was respectively2.82W/kgand1.81T, presenting that the magnetic property of silicon steel was improved. And withthe increase of boron content, the plasticity of silicon steel was improved.