Effect of metallic content on mechanical property of Ni/(10NiO-NiFe₂O₄) cermets

Abstract

Ni/ (10NiO-NiFe₂O₄) cermets were fabricated by using cold pressing-sintering method. The phase composition and effect of metallic content on the mechanical properties such as bending strength, Vickers’ hardness, fracture toughness and thermal shock resistance were studied. The results show that the cermets consist of Ni, NiO and NiFe₂O₄. Within the range of metallic content from 0 to 17% (mass fraction), the relative density decreases with the increase of metallic content and the decrease of sintering temperature, Vickers’ hardness decreases from 7 097 MPa to 4 814 MPa and the bending strength increases from 110 MPa to 157 MPa, and the fracture toughness reaches the optimal value of 5.11 MPa · m^1/2 at the metallic content of about 10%. The residual strength after thermal shock testing falls sharply as the thermal shock temperature difference is above 200 °C. The cermets samples, whose metallic content is 10% and 15%, respectively, exhibit promising property of thermal shock resistance at 960 °C with six cycles of heating and quenching testing.

Keywords

aluminum electrolysis / inert anode / NiFe₂O₄ / fracture toughness / thermal shock resistance