Optimizing FeSiCr-Based Soft Magnetic Composites Using the Deionized Water as the Phosphating Solvent

Area of Science:

• Materials Science
• Powder Metallurgy
• Soft Magnetic Materials

Background:

• Phosphating treatment is crucial for insulating magnetic powder surfaces in soft magnetic powder cores (SMCs).
• Traditional organic solvents (ethanol, acetone) for phosphating pose environmental risks.
• Developing environmentally friendly alternatives is essential for sustainable manufacturing.

Purpose of the Study:

• To investigate deionized water as a green solvent for phosphating FeSiCr powder.
• To prepare and characterize soft magnetic composites (SMCs) using deionized water-based phosphating.
• To evaluate the impact of phosphating solvents on SMC structure, magnetic properties, and corrosion resistance.

Main Methods:

• FeSiCr powder was phosphated using phosphoric acid with deionized water, ethanol, or acetone as solvents.
• SMCs were fabricated using phosphoric acid (inorganic) and modified silicon polymer (organic) coatings.
• Magnetic properties (permeability, saturation magnetization, core loss) and withstanding voltage were measured; structural analysis informed property correlations.

Main Results:

• Deionized water provides a more stable phosphating solution and promotes denser phosphate coatings than ethanol or acetone.
• Optimized phosphating with 0.2 wt.% phosphoric acid in deionized water at 35 °C yielded high effective permeability (25.7), quality factor (80.2), low core loss (709.5 mW/cm³), and high withstanding voltage (276 V).
• SMCs produced using deionized water exhibited superior corrosion resistance compared to those using organic solvents.

Conclusions:

• Deionized water is a viable and environmentally superior solvent for phosphating FeSiCr powder.
• This green approach significantly enhances the magnetic properties and corrosion resistance of soft magnetic composites.
• The findings offer a sustainable pathway for producing high-performance soft magnetic powder cores.