The magnetic and mechanical properties of SrFe12O19 magnets consolidated by Spark Plasma Sintering (SPS) or Conventional Sintering (CS) were optimised by varying addition of cellulose nanofibers (CNF), the addition of Bi2O3, sintering parameters and consolidation pressure. The optimum sintering conditions were identified based on the resulting magnetic and mechanical properties. In CS magnets, only the diffraction maxima of SrFe12O19 were present. In SPS magnets, there was a considerable decline in their hard-magnetic properties due to partial decomposition of SrFe12O19, while iron oxides and lower SrxFeyOz oxides were formed. The highest BHmax (16.3 kJ/m^3 ) was found for the SPS magnet sintered at 950 °C for 5 minutes with an applied pressure of 90 MPa and with no addition of CNF or Bi2O3. Comparing CS and SPS magnets with 1wt.% CNF, SPS sintering negatively affects the magnetic properties of the samples. The best BHmax (10.9 kJ/m^3 ) was measured for the CS magnet sintered at 1250 °C for 2 hours with a consolidation pressure of 150 MPa. The same can be observed in magnets with 2 wt.% CNF. The best BHmax (10.1 kJ/m^3 ) was found for the CS magnet sintered at 1200 °C for 30 minutes with consolidation pressure of 100 MPa and an addition of 4 wt.% Bi2O3. The fracture points and bending strengths in CS magnets with 1 wt.% CNF tend to be much higher than those without CNF. The highest fracture point (2500 MPa) was exhibited in a CS magnet with 1 wt.% CNF, sintered at 1200°C for 4h. Magnets with CNF are leaning toward pseudo-ductile behaviour, and the addition of CNF improved the mechanical properties of CS ferrites. The presented results show the potential of CS and SPS consolidation of SrFe12O19 with high mechanical properties and display the effect of CNF on the decrease in magnetic performance.
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