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Lead-free (0.90-x)(Bi1/2Na1/2)TiO3-0.05(Bi1/2K1/2)TiO3-x(Bi1/2Li1/2)TiO3-0.05BaTiO3 piezoelectric ceramics (abbreviated as BNKLBT-100x, with x ranged from 0 to 2.5 mol %) were prepared by a conventional mixed oxide method. Effects of the amount of (Bi1/2Li1/2)TiO3 (BLT) on the electrical properties and crystal structure of the BNKLBT ceramics were examined. BNKLBT-1.5 ceramics have good properties with piezoelectric constant d33=163 pC/N, electromechanical coupling factor kp=0.33, kt=0.53, relative permittivity εr=785 and dissipation factor cosδ=2.2% at 1 kHz. The sample has larger remnant polarization than BNKLBT-0 ceramics and the same coercive field as BNKLBT-0 ceramics. X-ray diffraction analysis shows that the incorporated BLT diffuses into the BNT–BKT–BT lattice to form a solid solution during sintering, but changes the crystal structure from rhombohedral to tetragonal symmetry at higher BLT amounts. Depolarization temperature (Td) of the BNKLBT-100x ceramics increases from 102 °C to ∼136 °C for BNKLBT-0 to BNKLBT-2.5. BNKLBT-1.5 is used as the transduction element in compressive type accelerometer and its sensitivity is calibrated by the back-to back method. Within the ±2.5% tolerance, the lead-free accelerometer has a mean value of 2.97 pC/ms-2 within 50 Hz–12.45 kHz and the lead-based accelerometer has a mean value of 4.34 pC/ms-2 within 50 Hz to 8.24 kHz. [ABSTRACT FROM AUTHOR]

A high sensitivity piezoelectric accelerometer has been developed by replacing the conventional piezoelectric rings with a cymbal transducer. The sensitivity of the cymbal-based accelerometers containing cymbal transducers with different endcap thicknesses and different seismic masses has been measured as a function of driving frequency. Due to the high d33′ coefficient of the cymbal transducers, the cymbal-based accelerometers have a high sensitivity of ∼97 pC/ms-2 with the amplitude rise of 2.85% (<1 dB) at one-third of the mounted resonance frequency (3.38 kHz). The effect of the seismic mass, the resonance frequency, and d33′ coefficient of the cymbal transducers on the sensitivity and the frequency range of the cymbal-based accelerometers are reported. [ABSTRACT FROM AUTHOR]