Nanostructured ZrO₂ membranes prepared by liquid-injection chemical vapor deposition

Abstract

Using the molecular compound Zr(OBut)₄ in a liquid-injection chemical vapor deposition process, microporous zirconia membranes were deposited on porous multi-layered alumina substrates consisting of a macroporous a-alumina base covered with a mesoporous c-alumina layer. The structure of nanocrystalline zirconia (ZrO₂), membranes formed by the thermal decomposition of the precursor varied depending on the decomposition temperature and the injection frequency. The deposited zirconia membranes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and atomic force microscopy (AFM). X-ray diffraction analysis patterns of the deposits obtained at 500 and 600 °C indicated a mixture of tetragonal and monoclinic ZrO₂ phases, whereas the fraction of the monoclinic phase increased at higher substrate temperature and injection frequency.