Selecting the best thermal barrier coating material for hot sections in gas turbine using AHP and TOPSIS multi-criteria decision making techniques

The use of thermal barrier coatings (TBC) in gas turbines provides good thermal insulation and protection of their components against erosion, which enables running them at high temperatures to produce more energy and increase their efficiency. In this study, selecting the best TBC material that allows the hot section components to operate at their peak performance and assure better durability is addressed by using two multi criteria decision making methods which are: Analytic Hierarchical Process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). The developed decision models consider the significant design factors of new generation novel TBCs; including: thermal properties (thermal conductivity and thermal expansion coefficient), phase stability, durability (erosion resistance, hot corrosion resistance, fracture toughness, oxidation resistance), and service temperature. Six novel TBCs (La₂Ce₂O_7, La₂Zr₂O_7, 8 YSZ, SrZrO_3, Gd₂Zr₂O_7, and Y₃Al₅O₁₂) were used as candidates for coating NIMONIC 263 substrate. In results, AHP model found La₂Ce₂O₇ as the best TBC for this application; the inconsistency test and sensitivity analysis indicate effective and reasonable materials ranking. The robustness of the created model was demonstrated by the TOPSIS result's agreement with the AHP result.