Crack propagation studies and bond coat properties in thermal barrier coatings under bending

Ray, Ashok K and Roy, Nilima and Godiwalla, K M (2001) Crack propagation studies and bond coat properties in thermal barrier coatings under bending. Bulletin of Materials Science, 24 (2). pp. 203-209.

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Ceramic based thermal barrier coatings (TBC) are currently considered as a candidate material for advanced stationary gas turbine components. Crack propagation studies under bending are described that were performed on plasma sprayed ZrO2, bonded by MCrAlY layer to Ni base superalloy. The crack propagation behaviour of the coatings at room temperature in as received and oxidized conditions revealed a linear growth of the cracks on the coating till the yield point of the super alloy was reached. High threshold load at the interface between the ceramic layer and the bond coat was required to propagate the crack further into the bond coat. Once the threshold load was surpassed the crack propagated into the brittle bond coat without an appreciable increase in the load. At temperatures of 800°C the crack propagated only in the TBC (ceramic layer), as the ductile bond coat offered an attractive sink for the stress relaxation. Effects of bond coat oxidation on crack propagation in the interface region have been examined and are discussed.

Item Type:Article
Official URL/DOI:
Uncontrolled Keywords:coating - thermal barrier - bond coat - superalloy - crack propagation - zirconia - plasma spraying - stress - strain - modulus
Divisions:Material Science and Technology
ID Code:780
Deposited By:Sahu A K
Deposited On:01 Jun 2010 11:51
Last Modified:08 Feb 2012 16:25
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