A paper published in The Journal of The Minerals, Metals & Materials Society investigates the degradation of protective coatings in gas turbine engines due to ingested debris by using thermodynamic modeling, including the Metal Oxide Solutions (TCOX) database from Thermo-Calc Software.
In the paper, Developments in Thermodynamic Models of Deposit-Induced Corrosion of High-Temperature Coatings, the recent progress in the development and application of thermodynamic models to understand deposit-induced degradation of advanced coatings in turbine engines was described. It also illustrates the power of these modeling approaches to predict coating behavior and accelerate the design of new coating materials and architectures. Comprehensive thermodynamic databases containing the components for both the deposits and coating materials and robust models were necessary for this investigation. Both the FToxid database and TCOX database were considered. Recent developments with our TCOX database made it a good candidate for this research.
The TCOX database was the most suitable one for the thermodynamic modeling to predict the intrinsic behavior of debris and deposits and reactions between deposits and the coating materials among databases that were compared.
It was found that the results from the TCOX10 database (TCOX database version 10) agreed with the experimental data of the equilibrium phases formed. Furthermore, TCOX10 also includes an improved model for silicate melt viscosity. This is required to provide reliable predictions of the deposit melt viscosity, which is an important parameter for this investigation. The author also states that Thermo-Calc has been proven useful in the identification of ranges of deposits relevant for this study and understanding their reactions with dense environmental barrier coating (EBC) and porous thermal barrier coating (TBC) materials.
The paper was written by David L. Poerschke, Assistant Professor at the University of Minnesota.