Preparation of HfO2–Al2O3 nanocomposite films using chemical vapor deposition

We prepared HfO2–Al2O3 nanocomposite films using chemical vapor deposition. Fibrous and lamellar microstructures formed in the monoclinic and tetragonal HfO2 (m/t-HfO2)–α-Al2O3 films at deposition temperature of 1573 K and Al mole fraction in the precursor vapor of 36–74 mol %Al2O3. Characterization by electron microscopy revealed that the m/t-HfO2 fibrous and lamellar structures are present throughout the α-Al2O3 columnar matrix above 50 mol %Al2O3 (55 vol %Al2O3), while α-Al2O3 lamellar structure was formed in m-HfO2 matrix below 50 mol %Al2O3.