Effects of dopants on grain growth of nano-sized BaTiO₃ powders prepared by citric acid-assisted spray pyrolysis

Nano-sized BaTiO₃ powders doped with Y, Eu and La components were prepared by ultrasonic spray pyrolysis from a spray solution with citric acid. The precursor BaTiO₃ powders had a large size, fractured and hollow structures irrespective of the type of dopant. The calcined BaTiO ₃ powders with and without dopants had nanometre sizes after a simple milling by hand using an agate mortar. The mean size of La-doped BaTiO ₃ powders measured from the transmission electron microscope (TEM) images was 38 nm at a calcination temperature of 700 °C. The mean crystallite sizes of the doped and undoped BaTiO₃ powders changed from 20 to 33 nm according to the type of dopant at a calcination temperature of 700 °C. An effective grain growth inhibition took place with the doped BaTiO₃ ceramics. The average grain sizes of La and Eu-doped BaTiO₃ ceramics were each 380 and 400 nm at a sintering temperature of 1280 °C.