Toughness Determination of Yttria + Tantala Co-Doped Stabilized Zirconia for TBC Applications

Co-doped thermal barrier coating ceramics are being explored for the purpose of increasing the resistance of current TBC materials to corrosion and erosion. Used in gas turbine engines, thermal barrier coating materials provide protection to super alloy components from the high temperatures needed to perform efficiently. Erosion caused by excessive heat or small particle contact lessens insulating capabilities of these ceramics, eventually exposing engine components. Due to tetragonal bonding, it is theorized that the yttria plus tantula systems offer high toughness characteristics. Proposed thermal barrier coating materials must meet or exceed state-of-the-art material toughness properties. Toughness values are realized by use of the Vickers Hardness Test for crack propagation. Resulting crack length is used along with the force applied to determine comparative numerical values. Compositions varying in percentages of yttria and tantula will be considered in search of a material to surpass current limits.