Abstract:5Ni/(10NiO−NiFe₂O₄) cermet materials were prepared by cold pressing sintering method in different atmospheres. The phase compositions were studied by XRD, microstructure was studied by SEM and mechanical properties were studied by three-point-bending strength and heat cycle. The results show that Ni/(NiO−NiFe₂O₄) cermet can be obtained by sintering in vacuum or atmospheres with oxygen content of 2×10⁻⁵, 2×10⁻⁴ and 2×10⁻³, respectively, but the phase composition of the ceramics varies greatly with oxygen content of the sintering atmosphere. The cermet tends to have a high content of NiO when sintered in vacuum. The content of NiFe₂O₄ and Ni in the cermet materials respectively increases and decreases with increasing oxygen in the sintering atmosphere. In the vacuum, cermet has an average grain size of 3.90 μm and bending strength of 138.59 MPa, which is able to withstand thermal shock tests 6.67 times in average.

Key words: nickel ferrite; cermet; mechanical property; sintering atmosphere