Tailoring thermal expansion of β-Cu2V2O7 with improved mechanical properties by incorporation of Li+Fe3+

Abstract

βCu2V2O7 is known to have a negative thermal expansion (NTE) in a wide temperature range but its ceramics bulk is very loose and porous. Herein, a strategy for sintering densely packed ceramics body with tailored coefficients of thermal expansion (CTE) and improved mechanical properties is presented, where Cu2+ is partially substituted by the combination of Li+ and Fe3+ according to the formula (LiFe)0.5xCu2-xV2O7. The results show that the CTEs can be tuned from negative to near-zero while the elasticity modulus and compressive strength are 2 and 15 times higher for x = 1.0 than those of β-Cu2V2O7, respectively. The reduced NTE is attributed to the stiffening and bond angle lessening of V-O1-V linkages while the elevated mechanical properties are ascribed to the densely packed nature of the samples.