Microstructure and Electrical and Mechanical Properties of Lithium Tantalate Ceramics Synthesized by a Sol-Gel Method

LiTaO3 ceramics has been produced from a fine powder synthesized by a sol-gel method from a Li,Ta-containing citrate precursor, and its microstructure and mechanical and electrical properties have been studied. Young’s modulus and microhardness of the ceramic lithium tantalite have been determined. The critical stress intensity factor of mode I KIC, which is a criterion for the crack resistance of a material, has been evaluated, and the effective fracture energy of the LiTaO3 ceramics has been determined. The complex impedance dispersion Z*(ω) has been studied, and temperature dependences of dielectric constant and conductivity have been measured in the temperature range ~300–705 K, which is crucial for the acoustoelectronic applications of ceramic lithium tantalate. In the temperature range studied, the static conductivity and relaxation time of LiTaO3 ceramics have been determined. The charge transport activation enthalpies for various temperature ranges have been estimated.