In-situ xrd characterization of multilayered ceramic composite systems for hypersonic applications

Material systems exposed to extreme environments associated with hypersonic Might are subjected to oxidation and thermal strains which contribute to failure. Polymer Derived Ceramic Composites (PDCC), with a coating of Ternary Coating System (TCS) acting as Environmental Barrier Coatings (EBCs) to prevent oxidation, are a promising concept to meet higher temperatures. However, this layered architecture can be prone to inter-face failure due to thermal strain incompatibility between the layers. The fundamental understanding of oxidation content gained throughout thermal profiles is paramount for the development of these material systems. In this work, a multilayered material system is fabricated and subjected to high temperatures. The growth of oxide phases in the top layers is characterized using synchrotron X-ray diffraction (XRD) at environments which simulate service conditions. At 1100°C, the titanium aluminum nitride (TiAIN) top coat developed an aluminum oxide (α-Al₂O₃) layer due to high temperature oxidation. The evolution of the aluminum oxide layer is shown through the change of peak integrated intensity between the cubic (111) TiAIN and the rhombohcdral (012) Al₂O₃ with respect to temperature. Oxide growth of α-Al₂O₃ and t-titania (t-TiO₂-rutile) is tracked throughout the thermal profile with respect to the TiAlN/TiN content. This unique in-situ characterization allows us to measure and better understand the mechanics of the high temperature multilayered systems that could be used for hypersonic leading edge applications.