Thermal barrier coating by electron beam-physical vapor deposition of zirconia co-doped with yttria and niobia
doi: 10.5028/jatm.2010.02026910

Daniel Soares de Almeida*
Institute of Aeronautics and Space
São José dos Campos – Brazil
dsalmeida@iae.cta.br

Carlos Alberto Alves Cairo
Institute of Aeronautics and Space
São José dos Campos – Brazil
ccairo@iae.cta.br

Cosme Roberto M. Silva
University of Brasília
Brasília – Brazil
cosmeroberto@gmail.com

Maria do Carmo A. Nono
National Institute for Space Research
São José dos Campos – Brazil
maria@las.inpe.br

*author for correspondence

Abstract:

The most usual ceramic material for coating turbine blades is yttria doped zirconia. Addition of niobia, as a co-dopant in the Y2O3-ZrO2 system, can reduce the thermal conductivity and improve mechanical properties of the coating. The purpose of this work was to evaluate the influence of the addition of niobia on the microstructure and thermal properties of the ceramic coatings. SEM on coatings fractured cross-section shows a columnar structure and the results of XRD show only zirconia tetragonal phase in the ceramic coating for the chemical composition range studied. As the difference NbO2,5-YO1,5 mol percent increases, the tetragonality increases. A significant reduction of the thermal conductivity, measured by laser flash technique in the zirconia coating co-doped with yttria and niobia when compared with zirconia-yttria coating was observed.

Keywords:

TBC, EB-PVD, Zirconia, Niobia, Thermal conductivity.

J. Aerosp.Technol. Manag., São José dos Campos, Vol.2, No.2, pp. 195-202, May-Aug., 2010
Received:19/05/10
Accepted:14/06/10