Journal of Materials Research

Articles

Yttria-stabilized zirconia crystallization in Al2O3/YSZ multilayers

Nihan Kemika1, Sergey V. Ushakova2, Meng Gua3, Nicole Schichtela4, Carsten Kortea4, Nigel D. Browninga5, Yayoi Takamuraa6 and Alexandra Navrotskya7 c1

a1 Peter A. Rock Thermochemistry Laboratory and Nanomaterials in the Environment, Agriculture and Technology Organized Research Unit (NEAT ORU), University of California, Davis, Davis, California; and Department of Chemical Engineering and Materials Science, University of California–Davis, Davis, California 95616

a2 Peter A. Rock Thermochemistry Laboratory and Nanomaterials in the Environment, Agriculture and Technology Organized Research Unit (NEAT ORU), University of California–Davis, Davis, California 95616

a3 Department of Chemical Engineering and Materials Science, University of California–Davis, Davis, California 95616

a4 Physikalisch-Chemisches Institut, Justus-Liebig Universität Gießen, Gießen, Germany. D-35392

a5 Department of Chemical Engineering and Materials Science, University of California–Davis, Davis, California 95616; Pacific Northwest National Laboratory, MSIN K8-87, Richland, WA 99352

a6 Department of Chemical Engineering and Materials Science, University of California–Davis, Davis, California 95616

a7 Peter A. Rock Thermochemistry Laboratory and Nanomaterials in the Environment, Agriculture and Technology Organized Research Unit (NEAT ORU), University of California–Davis, Davis, California; and Department of Chemical Engineering and Materials Science, University of California–Davis, Davis, California 95616

Abstract

Yttria-stabilized zirconia (YSZ)/Al2O3 multilayers deposited on Pt foil were studied by differential scanning calorimetry. Observed thermal effects were interpreted using additional evidence from x-ray diffraction and transmission electron microscopy. The crystallization temperature of YSZ increases from 344 to 404 °C as the layer thickness decreases from 15 to 4 nm. The enthalpy of crystallization becomes more exothermic with decreasing thickness, and it was measured to be −26 kJ/mol YSZ for 4-nm-thick layers and −12 kJ/mol for 15-nm-thick layers. The latter value is consistent with the reported crystallization enthalpy for YSZ powder of the same composition prepared by precipitation from aqueous solution. The more exothermic crystallization enthalpies for thinner films are indicative of a decrease in their degree of crystallinity. The 2–6-nm-thick Al2O3 layers remain amorphous when heated to 1000 °C. The described methodology enables thermal analysis of oxide thin films using commercial instruments.

(Received June 30 2011)

(Accepted December 06 2011)

(Online publication January 25 2012)

Key Words:

  • Calorimetry;
  • Film;
  • Phase transformation

Correspondence:

c1 Address all correspondence to this author. e-mail: anavrotsky@ucdavis.edu

0Comments