Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/41744

Title

Nanophase partially stabilized zirconia intermediate layer for strain accommodation in a multi-layer thermal barrier coating

Author(s)

Guru, D. N.;  Palacio, Manuel L B;  Mook, William M.;  Chambers, M. D.;  Heberlein, Joachim V. R.;  Gerberich, William W.;  Racek, Ondrej;  Berndt, Christopher C.

Abstract

Applying an environmental barrier coating (EBC) and a thermal barrier coating (TBC) on the next generation gas turbine structural materials such as silicon carbide matrix composites will lead to large stresses due to thermal expansion mismatch; thereby limiting the coating's effectiveness and lifetime. Nanostructured materials possess a large volume fraction of grain boundaries and are conjectured to partially relieve the strain in the coating structure. A Triple Torch Plasma Reactor (TTPR) was used to spray multi-layered TBCs consisting of a mullite EBC deposited either on a silicon carbide or a mullite substrate, a nano-phase partially stabilized zirconia coating (n-PSZ), and a yttria stabilized zirconia coating (YSZ) as the TBC. The nanostructure of the n-PSZ could be maintained during the deposition process. The coatings were heat treated at 1300°C and the change in microstructure and mechanical properties were analyzed using scanning electron microscopy (SEM), micro-indentation and scratch testing applied to the coating cross section. While a change in the microstructure was observed, in particular grain growth, the hardness and elastic modulus appeared to be little affected by the heat treatment giving a preliminary validation of the multilayer concept.

Publication type

Conference paper

Source

Thermal Spray 2004: Advances in technology and application: Proceedings of the International Thermal Spray Conference, Osaka, Japan, 10-12 May 2004, pp. 861-865

Publication year

2004

Keyword(s)

Central injection probe;  EBC;  Environmental barrier coating;  Grain boundaries;  Image analysis;  Microstructure;  Multi-layered coatings;  Nanostructured materials;  Plasma torches;  Scanning electron microscopy;  SEM;  Silicon carbide;  TBC;  Thermal barrier coatings;  Thermal expansion;  Triple Torch Plasma Reactor;  TTPR;  Zirconia

Publisher

ASM International

ISBN

9780871708090, 0871708094

Publisher URL

http://books.google.com/books?id=ZuO5x1lyRa0C

Peer reviewed