Ceramic composite membranes based on Bi3Ru3O11 – Bi1,6Er0,4O3 for obtaining of oxygen

Using hot uniaxial pressing in an argon atmosphere with a stress of 35 MPa and with holding at 800°C for 1 h, ceramic composites of Bi3Ru3O11–50 wt % Bi1.6Er0.4O3 and Bi3Ru3O11–65 wt % Bi1.6Er0.4O3 were obtained. It was found that phase composition of the composites does not change during gas chromatographic testing at 800°C and corresponds well to the specified one. The microstructure of the obtained composites was tested, and the formation of dense composites with a total porosity of less than 1% and with a uniform distribution of the Bi3Ru3O11 and Bi1.6Er0.4O3 components in the bulk of material was demonstrated. Transport properties (total conductivity, oxygen fluxes, and selectivity of separating oxygen over nitrogen) of the obtained composites at 600–800°C was investigated. Thus, at 800°C, the electrical conductivity of Bi3Ru3O11–50 wt % Bi1.6Er0.4O3 and Bi3Ru3O11–65 wt % Bi1.6Er0.4O3 was about 200 and 50 Ω–1 cm–1, respectively, while the metallic nature of their temperature dependence of conductivity is correlated to that for Bi3Ru3O11. The value of oxygen permeability for the obtained ceramic composites of about 7 × 10–9 mol cm–1 s–1 at 800°C, which is comparable to other membrane materials based on bismuth oxide, demonstrated the potential of their further use in the tasks for obtaining of pure oxygen from the air.