  The incessant technological pursuit towards a more sustainable and green
future depends strongly on permanent magnets. At present, their use is
widespread, making it imperative to develop new processing methods that
generate highly competitive magnetic properties reducing the fabrication
temperatures and costs. Herein, a novel strategy for developing dense sintered
magnets based on Sr-hexaferrites with upper functional characteristics is
presented. An innovative cold sintering approach using glacial acetic acid as
novelty, followed by a post-annealing at 1100 {\deg}C, achieves a densification
of the ceramic magnets of 92% with respect to the theoretical density and
allows controlling the particle growth. After the cold sintering process, a
fraction of amorphous SrO is identified, in addition to a partial
transformation to {\alpha}-Fe2O3 as secondary crystalline phase. 46 wt% of
SrFe12O19 remains, which is mostly recuperated after the post-thermal
treatment. These findings do not significantly modify the final structure of
ferrite magnets, neither at short- nor long-range order. The innovative process
has a positive impact on the magnetic properties, yielding competitive ferrite
magnets at lower sintering temperatures with an energy efficiency of at least
25%, which opens up a new horizon in the field of rare-earth free permanent
magnets and new possibilities in other applications.
