Evaluation of CaO-CeO2-partially stabilized zirconia thermal barrier coatings

Ramaswamy, Parvati ; Seetharamu, S. ; Varma, K. B. R. ; Rao, K. J. (1999) Evaluation of CaO-CeO2-partially stabilized zirconia thermal barrier coatings Ceramics International, 25 (4). pp. 317-324. ISSN 0272-8842

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/S0272-8842(98)00041-8


Plasma sprayable powders were prepared from ZrO2-CaO-CeO2 system using an organic binder and coated onto stainless steel substrates previously coated by a bond coat (Ni 22Cr 20Al 1.0Y) using plasma spraying. The coatings exhibited good thermal barrier characteristics and excellent resistance to thermal shock at 1000°C under simulated laboratory conditions (90 half hour cycles without failure) and at 1200°C under accelerated burner rig test conditions (500 2 min cycles without failure). No destabilization of cubic/tetragonal ZrO2 phase fraction occured either during the long hours (45 h cumulative) or the large number of thermal shock tests. Growth of a distinct SiO2 rich region within the ceramic was observed in the specimens thermal shock cycled at 1000°C apart from mild oxidation of the bond coat. The specimens tested at 1200°C had a glassy appearance on the top surface and exhibited severe oxidation of the bond coat at the ceramic-bond coat interface. The glassy appearance of the surface is due to the formation of a liquid silicate layer attributable to the impurity phase present in commercial grade ZrO2 powder. These observations are supported by SEM analysis and quantitative EDAX data.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:C. Thermal Shock Resistance; Thermal Barrier Coating; Partially Stabilized Zirconia; Plasma Spray
ID Code:91070
Deposited On:16 May 2012 08:20
Last Modified:16 May 2012 08:20

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