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Nickel ferrite powders were prepared by combustion synthesis of Fe, Fe 2 O 3 and NiO using NaClO 4 as fuel. Nickel ferrite ceramics were fabricated by single-step and two-step sintering under various conditions. The effects of each sintering process on the densification, microstructure and properties of the ceramics were investigated. X-ray diffraction analysis of asprepared powders and as-fabricated ceramics confirmed a single-phase NiFe 2 O 4 with a cubic spinel crystal structure. Single-step sintering produced ceramics with a wider density range (3.63-3.97 g/cm 3 ) than two-step sintering (3.74-3.84 g/cm 3 ) and a wider grain size range (1.10-2.31 µm compared to 1.30-1.37 µm). Two-step sintering produced ceramics with greater microhardness (135.00-172.60 HV) than single-step sintering (65.33-153.00 HV). In both methods, higher sintering temperatures produced ceramics with greater saturation magnetization (M s ). The highest M s values were 62.84 emu/g from single-step sintering at 1200°C and 70.00 emu/g from two-step sintering at T 2 = 1150°C: H c was, respectively, 31.18 and 22.00 Oe. The ceramic sintered by the two-step method at T 2 of 1150°C presented superparamagnetic-like behavior of multi-domain magnetic materials, with high µ i and very low H c . The higher electrical resistivity (R), dielectric constant (ε r ) and quality factor of this ceramic support highfrequency data storage applications.

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