Retained strength of UHTCMCs after oxidation at 2278 K

Abstract

In the frame of Horizon 2020 European C 3 HARME research project, the manufacture of ZrB2-based CMCs was developed through different processes: slurry infiltration and sintering, radio frequency chemical vapour infiltration (RF-CVI) and reactive metal infiltration (RMI). To assess the high temperature stability, room temperature bending strength was measured after oxidizing the samples at 2278 K and compared to the strength of the as-produced materials. Microstructures were analysed before and after the thermal treatment to assess the damage induced by the high temperature oxidation. Short fibre-reinforced composites showed the highest retained strength (>80 %) and an unchanged stress-strain curve.

A systematic approach for horizontal and vertical scale up of sintered Ultra-High Temperature Ceramic Matrix Composites for aerospace – Advances and perspectives

“…In previous works, the high temperature flexural strength of these composites was generally higher than room temperature values [12,15,36,37]. This trend was confirmed in this study, see the loaddisplacement curves in Fig.…”

“…Previous works have already identified the several steps involved in the development of these composites, such as the design of matrix compositions, development of new processes including manual fibre preform impregnation or filament winding [12], densification of the composites through hot pressing or spark plasma sintering [10], mechanical characterization at room and elevated temperature, oxidation studies from 1500 to 2100 °C and arc jet tests in plasma wind tunnel facilities [10,[13][14][15][16]. Results obtained have shown that similar microstructures and properties can be achieved by HP and SPS, with a reduction of temperature and processing time in case of SPS [17,18].…”

Propulsion tests on ultra-high-temperature ceramic matrix composites for reusable rocket nozzles

“…Neither coating is applied to the fiber, no external TBC is applied. This approach was widely developed during the EU project C 3 HARME [36,37]. Sintering of these UHTCMCs through methods typical of bulk ceramic science (e.g.…”

“…For the matrix of UHTCMCs, ZrB2/SiC powder mixtures were prepared by wet ball milling and drying. With these mixtures, water-based slurries were prepared using polyacrylates at different molecular weight as dispersants to adjust the fiber volumetric amount [37,43]. The composites were fabricated by infiltrating the fabrics with the slurries with subsequent stacking in a predefined sequence and sintering by hot pressing or spark plasma sintering at temperatures between 1800 -1930°C under 30 MPa of pressure.…”

“…In the second and third simulations, the presence of a 60 μm-thick oxide layer over the whole nozzle inner surface was taken into account. In the second simulation ("Oxidized -k = 2 W/m‧K" ), this layer was characterized by a specific heat equal to 650 J/kg‧K and a thermal conductivity of 2 W/m‧K, according to a previous authors' work [37]. In the third simulation ("Oxidized -k = 1 W/m‧K" ), for an additional parametric analysis taking into account possible factors leading to reduction in thermal conduction through the oxide, such as porosity, the oxide layer thermal conductivity was set to 1 W/m‧K [64][65][66].…”