Phase transformation of ZrO2 nanocrystals induced by Li+

It is well known that monoclinic ZrO2 nanocrystals can be synthesized at similar to 1000 degrees C by sol-gel method. In this letter, we demonstrate a novel method to synthesize monoclinic ZrO2 nanocrystal through sol-gel technique under relatively lower calcined temperature. It is found that composition of monoclinic ZrO2 can be significantly enhanced by doping Li+, and pure monoclinic phase ZrO2 nanocrystals appear at 900 degrees C. 800 degrees C and 700 degrees C for samples doped with 0.5, 2, and 5 mol% Li+, respectively. This phase transformation of ZrO2 is dependent on the crystallite size and there is a range of around 11-35 nm of crystallite size in which tetragonal and monoclinic ZrO2 coexist. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.