Structures and properties of Sr-doped NdCrO3 solid solutions

Abstract

Abstract Strontium doped NdCrO 3 solid solutions (0.05 ≤ x ≤ 0.25) were synthesized using a solid-state reaction. The effects of Sr doping on the structures, electrical and thermal expansion properties of the solid solutions were studied. The results show that all the solid solutions prepared possess a single phase orthorhombic perovskite structure at room temperature. With the increase of Sr content in Nd site, the cell volume of Nd 1− x Sr x CrO 3 solid solutions decreases gradually. The sinterability of the solid solutions is remarkably improved compared with pure NdCrO 3 . The relative densities of the samples are all higher than 96%, among which Nd 0.75 Sr 0.25 CrO 3 sample presents the highest value of 97.8%. Both the electrical conductivity and the thermal expansion coefficient (TEC) of Nd 1− x Sr x CrO 3 increase with the increase of Sr content. Sample Nd 0.75 Sr 0.25 CrO 3 exhibits the highest electrical conductivity of 1.73 × 10 3 S m −1 at 850 °C in air. And it also attains the highest TEC of 9.45 × 10 −6 K −1 over temperature range from 30 to 1000 °C, which is basically compatible with that of yttria stabilized zirconia (10.3 × 10 −6 K −1 ). Nd 0.75 Sr 0.25 CrO 3 may be considered as a promising interconnect material for solid oxide fuel cells according to the electrical and thermal expansion behaviors.