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

Boosting the High Performance of BiFeO3-BaTiO3 Lead-Free Piezoelectric Ceramics: One-Step Preparation and Reaction Mechanisms

“…The enhanced piezoelectric and ferroelectric properties are related to the pinning of the domain wall by β-Bi 2 O 3 , i.e., domain motion occurred easily after impurities were eliminated . A comparison of the maximum d 33 values for various BF- x BT-based piezoceramics with respect to their T sint (Figure d) indicates that our B (1+ y ) F-0.3BT (−0.01 ≤ y ≤ 0.02) ceramics outperformed almost all BF- x BT-based piezoceramics at T sint ≤ 970 °C. − ,,− The exception is when BF-0.3BT was sintered above 1000 °C, which provided a slightly higher d 33 of 214 pC/N than those of our ceramics, but its preparation technology is more complicated than our one-step preparation, in addition to its high T sint .…”

“…Room-temperature electrical properties of B 1.02 F- x BT (0.25 ≤ x ≤ 0.33) ceramics: (a–c) P – E curves, bipolar S – E loops, and unipolar S – E loops; (d) d 33 and T sint of various BF- x BT-based piezoelectric ceramics using the conventional solid-state method with a furnace-cooling technique; the red solid circle is from this work, and the open symbols and the digits in panel (d) are from references. − ,,− …”

“…This eliminates Bi 25 FeO 39 and produces only BF- x BT. Most researchers prepared BF- x BT ceramics by separate calcination and sintering procedures, in which BF- x BT powders were synthesized at T cal ≤ 800 °C and then sintered at T sint ≥ 930 °C to obtain BF- x BT ceramics. − ,,− The reactions in these methods can be understood by this mechanism. When T ≤ 800 °C, Bi 3+ diffuses to Fe 2 O 3 to form BF- x BT containing un-BaTiO 3 /R-BiFeO 3 , Bi 25 FeO 39 , and a small amount of Fe 2 O 3 .…”

“…Considerable efforts have been put into studying the role of sintering additives in the BF- x BT system. The effects of Li 2 CO 3 and CuO on T sint and other properties were investigated in 0.7BiFeO 3 -0.3BaTiO 3 -0.0035MnCO 3 + 0.002Li 2 CO 3 + x CuO, which achieved a low T sint of 930 °C and a moderate d 33 of 168 pC/N . When 3% Li 2 CO 3 was added to BiFeO 3 -BaTiO 3 -Bi­(Zn 0.5 Ti 0.5 )­O 3 as a sintering assistant, d 33 improved to 184 from 166 pC/N at T sint = 970 °C .…”

“…The effects of Li 2 CO 3 and CuO on T sint and other properties were investigated in 0.7BiFeO 3 -0.3BaTiO 3 -0.0035MnCO 3 + 0.002Li 2 CO 3 + xCuO, which achieved a low T sint of 930 °C and a moderate d 33 of 168 pC/N. 35 When 3% Li 2 CO 3 was added to BiFeO 3 -BaTiO 3 -Bi(Zn 0.5 Ti 0.5 )O 3 as a sintering assistant, d 33 improved to 184 from 166 pC/N at T sint = 970 °C. 36 However, the addition of a sintering assistant made it difficult to tailor the phase structure and regulate defects.…”