Advanced Manufacturing of Novel Oxide Composites for Reusable Leading Edges

Project Overview

Ceramic coatings are essential components in thermal and environmental barrier systems for hot zone and corrosion protection in gas turbines. 7-8 mol% yttria-stabilized zirconia (YSZ) protective layer is considered the gold standard. However, the ultimate working temperature of the YSZ coating (1200°C) is a critical bottleneck to achieving higher operating temperatures. To this day, a material system that can survive temperatures greater than 1800 °C does not exist. The goal of this LW LDRD is to develop thermal barrier coating centering around A6Ta2O17 (A=Hf or Zr) superstructure oxides. Hf6Ta2O17 and Zr6Ta2O17 were systematically synthesized, and their mechanical properties and oxygen diffusivities were evaluated. Both Hf6Ta2O17 and Zr6Ta2O17 show remarkably low oxygen diffusivity (2-3x better) while having comparable mechanical properties compared to the current state-of-the-art 8YSZ coating ceramic. Furthermore, The Hf6Ta2O17 coating – ZrB2/SiC substrate system survived 11 rapid heating up to 1800 °C and cooling cycles before coating failure without compromising the substrate material. The testing temperature is beyond the service conditions of 8YSZ by about 600 °C indicating a superior thermal protective performance. The fundamental understandings gained from the project strengthen our subject matter expertise in materials for extreme environments to meet the growing need for improved thermal barrier coatings.

Mission Impact

Hf6Ta2O17 and Zr6Ta2O17 are superior oxide materials compared to the current state-ofthe-art 8YSZ coating ceramic. The projects provided fundamental understanding and developed thermal barrier coating technology to meet the future national security challenges. We standardize the test procedure for high temperature torch testing as a high-throughput screening tool to strengthen our subject matter expertise in materials for extreme environments to meet the growing need for improved thermal barrier coatings. 

Publications, Presentations, and Patents

Cahill, James T. and Qirong Yang. “Shape-Stable Structures with Ablative Cooling.” Patent IL-1373.

Yang, Qirong, Harry Charalambous, Elizabeth M. Sobalvarro, Jesus Rivera, Peter WF Evans, James T. Cahill, Wyatt L. Du Frane, and Joshua D. Kuntz. "Synthesis, sintering, and grain growth kinetics of Hf6Ta2O17." Journal of the European Ceramic Society 43, no. 10 (2023): 4541-4548.

Qirong Yang, Harry Charalambous, Elizabeth M. Sobalvarro, Jesus Rivera, Peter WF Evans, James T. Cahill, Wyatt L. Du Frane, and Joshua D. Kuntz, "Functionally graded thermal protective systems using Hf6Ta2O17" (Presentation, Composite, Materials, & Structures Conference, St. Augustine, FL, Jan 2023).

Qirong Yang, Harry Charalambous, Elizabeth M. Sobalvarro, Jesus Rivera, Peter WF Evans, James T. Cahill, Wyatt L. Du Frane, and Joshua D. Kuntz, "High-temperature Hf6Ta2O17 oxide coating" (LLNL Postdoc Poster Session, Livermore, CA, April 2023).

Qirong Yang, Harry Charalambous, Elizabeth M. Sobalvarro, Jesus Rivera, Peter WF Evans, James T. Cahill, Wyatt L. Du Frane, and Joshua D. Kuntz,"Synthesis and consolidation of Hf6Ta2O17 for thermal protected layered composites" (LLNL Postdoc Presentation, Livermore, CA, August 2022).