Effect of sintering atmosphere on phase composition and mechanical property of 5Cu/(10NiO-NiFe2O4) cermet inert anodes for aluminum electrolysis

Abstract

5Cu/(10NiO-NiFe2O4) cermet anodes were prepared by the cold-pressing sintering method in different atmospheres. Furthermore, their phase composition, microstructure and mechanical properties were also investigated. The results reveal that 5Cu/ (10NiO-NiFe2O4) ceramic material can be obtained by sintering in the vacuum (oxygen content is 0.02ppm) or atmospheres of Ar + air with oxygen content of 10ppm, 200ppm, 2000ppm, and 10000ppm respectively, and phase composition of the ceramics varies with oxygen content of the sintering atmosphere, greatly. Content of NiFe 2O4 in the ceramic materials increases with the increase of oxygen content in the sintering atmosphere, But content of phase Cu decreases with the increase of oxygen content. When oxygen content in the atmosphere is 10ppm, the grain size of 5Cu/ (10NiO-NiFe2O4) cermet is 5.43 μm, meanwhile the bending strength reaches 80.05 MPa at the room temperature.