Solvent-assisted spark plasma sintering of SrFe12O19 permanent magnets

The increased demand expected for permanent magnets in the next few years and the need for a more sustainable production in the ceramic industry bring forward the need to develop new and greener processes. Herein, spark plasma sintering is employed to consolidate strontium hexaferrite magnets at lower sintering temperatures by adding a transient solvent, such as glacial acetic acid, to the starting powder. The addition of a solvent activates the onset of mass transport at reduced temperatures, leading to dense pieces with relative densities above 95% at 850 °C, lower than those reported in previous studies. An optimized solvent-assisted spark plasma sintering strategy is established, allowing us to identify the parameter ranges that lead to a trade-off between relative density and coercivity. The results presented unveil that integrating solvent-assisted approaches with advanced sintering techniques can be a powerful pathway for the development of new strategies for production of ceramic permanent magnets.