Method of estimating the lifetime of thermal barrier coatings

US6681639B2 · kind B2 · utility

Assignee

• ALSTOM (Switzerland) Ltd · CH

Inventors

• Otto Bernhardi · Bad Schönborn, DE
• Roland Muecke · Windisch, CH
• Hans Joachim Schmutzler · Maikammer, DE
• Christoph Sommer · Plankstadt, DE
• Marianne Sommer · Walldorf, DE

Key dates

• Filing date: Apr 12, 2002
• Grant date: Jan 27, 2004
• Expiry date: Apr 22, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N17/00
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method of estimating the lifetime of a thermal barrier coating (14), which is applied to the surface of a member subjected to cyclical thermal loads, especially a vane and/or blade of a gas turbine, by means of a bond coat (12) lying in between the coating and the member, leads to more accurate results with simplified calculation by determining, in a first step, the amplitude of the normal stress (&Dgr;&sgr;n) perpendicular to the interface between the bond coat (12) and the thermal barrier coating (14) during cyclical loading, and calculating, in a second step, the number Ni of cycles to failure for every normal stress amplitude (&Dgr;&sgr;n) in accordance with the formula where &sgr;0 is a stress reference value and C(&dgr;ox) and m(&dgr;ox) are material parameters, which depend on the thickness (&Dgr;ox) of an oxide layer (13), which is located between the thermal barrier layer (14) and the bond coat (12) and grows with the cyclical loading.