Thermal stability of polymer derived ultra-high temperature ceramic matrix composites
- Paper number
IAC-23,C2,4,3,x78092
- Author
Dr. Luca Zoli, CNR - ISSMC, Italy
- Coauthor
Dr. Francesca Servadei, CNR - ISSMC, Italy
- Coauthor
Dr. Diletta Sciti, CNR - ISSMC, Italy
- Year
2023
- Abstract
The demand for materials that can withstand temperatures exceeding 2000 °C is increasing for the production of the next generation of leading edges, thermal protection systems (TPS), rocket nozzles, and turbine blades for propulsion in hypersonic vehicles. To address this need, ultra-high temperature ceramic matrix composites (UHTCMCs) have emerged as a novel class of materials that can surpass the limitations of existing materials. For example, silicon carbide matrix composites (SiC/SiC and C/SiC) are limited to temperatures below 1800°C, while carbon/carbon is not limited in temperature but shows low wear and oxidation resistance. UHTCMCs typically consist of a matrix of ultra-high temperature ceramic (UHTC) phases belonging to borides, carbides, or nitrides of groups IV and V metals, which are reinforced with carbon fibers. In addition to their high-temperature properties, UHTCs also exhibit excellent wear resistance and chemical stability, making them attractive for use in harsh chemical environments.[1-7] This study investigates the thermal stability and mechanical properties of a ZrB2/SiC/Cf ultra-high temperature ceramic matrix composite (UHTCMC) fabricated through powder slurry infiltration (SI) and six cycles of Polymer Infiltration and Pyrolysis (PIP) with allylhydrido polycarbosilane (SMP-10 from Starfire Systems, Inc.). [8,9] The material was first investigated after consolidation under mild conditions at 1000 °C, at which point the polymer-derived SiC remained amorphous. Post-consolidation thermal treatments were then carried out at temperatures ranging from 1100 °C to 1900 °C to evaluate the microstructural evolution of the matrix, including crystallization and an increase in porosity. Finally, elevated temperature mechanical properties were studied through bending tests up to 1500 °C. Post pyrolysis heat treatments up to 1400 °C did not significantly affected the porosity neither the morphology of SiC(O), while annealing at temperature of 1500 °C and beyond led to conversion of amorphous SiC(O) into crystalline β-SiC and consequently to an increase of open porosity up to 30%. Strength of annealed composites above 1500 °C resulted in performance deterioration at room temperature, reaching values not higher than of 215 MPa. Tests at 1500 °C revealed an improvement of the strength compared to material consolidated at mild conditions. Annealing at 1400 °C was identified as the best trade-off to balance performance and cost effectiveness to achieve dense materials with excellent performance up to 1500 °C. Annealing at 1700 °C was identified as the minimal heat treatment to complete crystallization of SiC as well as the removal of oxide impurities on ZrB2 and SiC grains.
- Abstract document
- Manuscript document
IAC-23,C2,4,3,x78092.pdf (🔒 authorized access only).
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