Hydrothermal Synthesis of Acicular Lead Titanate Fine Powders

Abstract

A pure, acicular lead titanate (PbTiO 3 ) fine powder with a white color has been prepared by hydrothermal synthesis. It is a new phase of PbTiO 3 with I 4 symmetry, cell parameters of a = 12.358 Å and b = 14.541 Å, and a density of 6.80 g.cm −3 . The influences of pH (12.5 to 14.4), Pb/Ti ratio (1.0 to 1.6) in the feedstock, reaction temperature (130° to 230°C), time (0.25 to 4 h), starting materials, and additives on the formation of acicular PbTiO 3 under hydrothermal conditions have been investigated. The acicular PbTiO 3 with I 4 symmetry, referred to as the PX phase, can be converted to the perovskite‐type (PE phase) of PbTiO 3 at about 605°C while its acicular morphology is essentially unchanged. The preferable conditions for preparing pure acicular PX‐phase PbTiO 3 are that the pH is 13.0 to 14.0, Pb/Ti ratio is >1.3, reaction temperature is 170° to 200°C, time is 0.5 to 1.0 h, titanium butoxide (Ti[O(CH 2 ) 3 CH 3 ] 4 ) is the starting material, and poly(vinyl alcohol) is an additive. The acicular grain of the PX phase is usually less than 100 nm in diameter and more than 1000 nm in length.