Facile fabrication of cordierite-based porous ceramics with magnetic properties

In this paper, cordierite-based porous ceramics with magnetic properties have been firstly in-situ synthesized by using MgO, Al₂O₃, and SiO₂ powders as raw materials and Fe₃O₄ as a functional additive. Combining with the foam freeze casting method, near net size fabrication (total linear shrinkage < 2.86%) of the magnetic porous materials was realized by adjusting the amount of Fe₃O₄. The porosity, compressive strength, and saturation magnetization of the prepared materials were 83.9%–87.8%, 1.51–2.65 MPa, and 1.2–5.8 emu/g, respectively. The phase composition and microstructure evolutions during sintering were investigated briefly. The results showed that the synthesis temperature of cordierite was lowered about 100 ℃ due to the addition of Fe₃O₄. Except for the main phase-cordierite, Mg–Al–Fe spinel and α-Fe₂O₃ also existed in the final materials. The lattice parameters of the Mg–Al–Fe spinel and the amount of α-Fe₂O₃ changed obviously with the change in the sintering temperature and Fe₃O₄ amount, which mainly influenced the magnetic properties of the prepared materials. Thus, a facile fabrication method of the cordierite-based porous ceramics with the magnetic properties has been put forward in this paper.