Effect of organic solvent on the cold sintering processing of SrFe12O19 platelet-based permanent magnets

[EN] In this work we have investigated the effect of the solvent during the processing of SrFeO platelet-based permanent magnets by cold sintering process (CSP) plus a post-thermal treatment. Several organic solvents: glacial acetic acid, oleic acid and oleylamine have been analyzed, optimizing the CSP temperatures at 190−270 °C, under pressures of 375−670 MPa and 6−50 wt% of solvent. Modifications in the morphological and structural properties are identified depending on the solvent, which impacts on the magnetic response. Independently of the solvent, the mechanical integrity of ferrite magnets obtained by CSP is improved by a post-annealing at 1100 °C for 2 h, resulting in relative densities around 92 % with an average grain size of 1 μm and a fraction of SrFeO phase >91 %. H ≥ 2.1 kOe and M of 73 emu/g are obtained in the final sintered ceramic magnets, exhibiting the highest H value of 2.8 kOe for the magnet sintered using glacial acetic acid.This work has been supported by the Ministerio Español de Ciencia e Innovación (MICINN) through the projects MAT2017-86540-C4-1-R and RTI2018-095303-A-C52, and by the European Commission through Project H2020 No. 720853 (Amphibian). Part of these experiments was performed at the CLAESS beamline at ALBA Synchrotron with the collaboration of ALBA staff. A.S. acknowledges financial support from Comunidad de Madrid for an “Atracción de Talento Investigador” Contract (2017-t2/IND5395). C.G.-M. and A.Q. acknowledge financial support from MICINN through the “Juan de la Cierva” Program (FJC2018-035532-I) and the MICINN through the “Ramón y Cajal” Contract (RYC-2017-23320),Peer reviewe