The effects of propionic acid on nano-sized BaTiO3 particles synthesized by a hydrothermal method.

The influence of propionic acid on BaTiO3 particles prepared via hydorthermal method is discussed. The amount of the acid is varied in the experimental processes to enhance understanding of the roles of the propionic acid. Smaller sized BaTiO3 powders with more uniform particle sizes can be achieved at 200 degrees C after 24 h using propionic acid. The acid is found to be excellent for size reduction and narrow size distribution. Reitveld refinement of the XRD patterns revealed that the synthesize BaTiO3 nanopowders have tetragonal asymmetry dominant structures. The "micro-capsules" caused by the acid are observed using high temperature in-situ TEM analysis. High vacuum condition of the TEM is attributed to the notable differences. It can thus be posited that the reduction of particle size and the narrow size distribution result from the "micro-capsule" effects of propionic acid. Moreover, the "capsules" are attributed to a decrease of intragranular pores in the BaTiO3 particles.