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.
TCS Metal Oxide Solutions Database (TCOX) is a thermodynamic database for slags and oxides. The intended application is for solid and liquid ionized materials, for example oxides or sulfides. Despite the name of the database, it can also be used for fluoride and sulfide systems without oxygen.The database includes thermodynamic data plus properties data for molar volume and viscosity of ionic liquids, and as of version 11 (TCOX11), it also includes surface tension. Additionally, TCOX11 includes 29 elements and 550 assessed phases.