Development of the Advanced TBC for High Efficiency Gas Turbine

Since 2004, Mitsubishi has been pursuing a 1,700°C gas turbine as part of the Japanese National Project [1][2]. One of the most important key technologies for the target is thermal barrier coatings (TBCs) which are capable of improving cooling efficiency of hot parts. With increasing the turbine inlet temperature, TBCs surface temperature is also rising up. In addition, the temperature gradient through TBCs thickness must steepen as a result of keeping metal temperature. Both have a significant effect on durability such as spallation and erosion of TBCs. To evaluate these issues, thermal cycle test and hot erosion test were introduced. After the screening of those component tests, the advanced TBCs coated in the first unit of M501J were verified at our pilot plant called T-point. Sound condition for row 1 blades and vanes had been confirmed after over 3 year operation.