Effect of BaO addition on electric conductivity of xCu/10NiO-NiFe2O4 cermets
(State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: The effects of BaO addition on the phase composition, relative density and electric conductivity of xCu/10NiO-NiFe2O4 (x=5, 10) cermets were studied, which were prepared with cold isostatic pressing-sintering process. The results show that the relative densities of 5Cu/10NiO-NiFe2O4 cermet doped with 1% BaO (mass fraction) and 10Cu/10NiO-NiFe2O4 cermet doped with 1% BaO sintered at 1 473 K in nitrogen atmosphere, are increased by about 9.86% and 9.75% compared with the undoped BaO cermets, respectively. And the electric conductivities 22.79 S/cm of 5Cu/10NiO-NiFe2O4 cermets adding 1% BaO and 23.10 S/cm of 10Cu/10NiO-NiFe2O4 cermets adding 1% BaO are obtained, which are 2.21 times and 1.47 times of those of undoped samples, respectively. Moreover, the 10Cu/10NiO-NiFe2O4 cermets doped with 1% BaO have a maximum σ0 of 58.91 S/cm and electric conductivity of 23.10 S/cm at 1 233 K. Maybe low melting-point phases of BaFe2O4 and Ba2Fe2O5 have an excellent electric conductivity in xCu/10NiO-NiFe2O4 (x=5, 10) cermets at 1 233 K.
Key words: Cu/10NiO-NiFe2O4 cermet; BaO; inert anode; aluminum electrolysis; electric conductivity; relative density