Water-Induced Degradation in (Bi1/2Na1/2)TiO3 Lead-Free Ceramics

Chemical stability of (Bi 1/2 Na 1/2 )TiO 3 (BNT) ceramics against water was studied through a comparison experiment. Immersion of BNT in 0.01 M NaOH solution showed no noticeable influence, while BNT ceramics were seriously affected when hydrogen was deposited on them through the electrolysis of water in the solution: the capacitance was obviously decreased and the dielectric loss was dramatically increased in the low-frequency range. X-ray diffraction analysis indicated that hydrogen was first dissolved into BNT and then caused decomposition, with some other phases formed. As water-induced degradation is an important cause of degradation for piezoelectric devices, it is important to ensure that the chemical stability of BNT is not decreased when using doping and/or the formation of a solid-state solution with other perovskite-type oxides. in order to improve the piezoelectric properties of BNT-based ceramics.