Li Xiangdong, Yu Hongya, Wang Hongxiang, Yuan Tongxin, Liu Zhongwu
School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.
South China Institute of Collaborative Innovation, Dongguan 523808, China.
Materials (Basel). 2024 Apr 2;17(7):1631. doi: 10.3390/ma17071631.
To prepare a soft magnetic powder core, the magnetic powder surface has to be insulated by phosphating treatment. Organic chemicals such as ethanol and acetone are generally used as solvents for phosphoric acid, which may cause serious environmental problems. This work proposed deionized water as the environmentally friendly phosphating solvent for FeSiCr powder. The soft magnetic composites (SMCs) were prepared using phosphoric acid for inorganic coating and modified silicon polymer for organic coating. The effect of different phosphating solvents, including deionized water, ethanol, and acetone, on the structure and magnetic properties of SMCs were investigated. It is found that the solvent affects the phosphating solution's stability and the phosphoric acid's ionization. The phosphoric acid is more stable in deionized water than in ethanol and acetone. The phosphating reaction in deionized water is also more stable in deionized water, resulting in a dense phosphate coating on the particle surface. The effects of phosphoric acid concentration and temperature on the magnetic properties of FeSiCr-based SMCs were further studied. With the increase in phosphoric acid concentration and temperature, the magnetic permeability and saturation magnetization of the powder core decrease, and the core loss decreases, followed by an increase. The optimized combination of properties was obtained for the SMCs phosphated with 0.2 wt.% phosphoric acid in deionized water at 35 °C, including a high effective permeability of 25.7, high quality factor of 80.2, low core loss of 709.5 mW/cm measured at 0.05 T @ 100 kHz, and high withstanding voltage of 276 V, due to the formation of uniform and dense insulating coating layers. In addition, the SMCs prepared with phosphated powder show good corrosion resistance. The anti-corrosion properties of the SMCs using deionized water as a phosphating solvent are better than those using ethanol and acetone.
为制备软磁粉芯，磁粉表面需通过磷化处理进行绝缘。乙醇和丙酮等有机化学品通常用作磷酸的溶剂，这可能会导致严重的环境问题。本工作提出将去离子水作为FeSiCr粉末的环保型磷化溶剂。使用磷酸进行无机涂层和改性硅聚合物进行有机涂层来制备软磁复合材料（SMC）。研究了包括去离子水、乙醇和丙酮在内的不同磷化溶剂对SMC结构和磁性能的影响。发现溶剂会影响磷化溶液的稳定性和磷酸的电离。磷酸在去离子水中比在乙醇和丙酮中更稳定。去离子水中的磷化反应也更稳定，导致颗粒表面形成致密的磷酸盐涂层。进一步研究了磷酸浓度和温度对FeSiCr基SMC磁性能的影响。随着磷酸浓度和温度的升高，粉芯的磁导率和饱和磁化强度降低，铁损先降低后升高。在35℃下用0.2 wt.%磷酸在去离子水中磷化的SMC获得了优化的性能组合，包括在0.05 T @ 100 kHz下测量的25.7的高有效磁导率、80.2的高品质因数、709.5 mW/cm的低铁损以及276 V的高耐压，这归因于形成了均匀致密的绝缘涂层。此外，用磷化粉末制备的SMC具有良好的耐腐蚀性。使用去离子水作为磷化溶剂的SMC的耐腐蚀性能优于使用乙醇和丙酮的SMC。
