Effects of Li2CO3 and CuO as Composite Sintering Aids on the Structure, Piezoelectric Properties, and Temperature Stability of BiFeO3-BaTiO3 Ceramics

In order to reduce the sintering temperature of ceramics, the effects of binary composite sintering aids, Li2CO3 and CuO, on the sintering temperature and properties of 0.7BiFeO3-0.3BaTiO3-0.0035MnCO3 + 0.002Li2CO3 + xCuO (BF-BT-LC + xCuO) ceramics were studied by traditional solid-state sintering. The results show that the sintering liquid phase can effectively promote the sintering of BF-BT-LC + xCuO ceramics by adding a certain amount of Li2CO3 and changing the amount of CuO. The samples sintered at 930°C/2 h with 0.4 mol.% CuO get a piezoelectric constant d33 = 168 pC/N, an electromechanical coupling coefficient kp = 0.302, and a mechanical quality factor Qm = 31.207. The addition of CuO was conducive to obtaining stable BF-BT-LC + xCuO piezoelectric ceramics. We conclude that the composite sintering aids, Li2CO3 and CuO, can effectively promote the sintering of BF-BT-LC + xCuO, which is beneficial to obtain BF-BT-LC + xCuO ceramics with a wide sintering temperature range and stable properties.