Each claim states how it is known and cites its evidence.
EstablishedTechnical ceramic matrix reinforced with fibres, whiskers or particles.
In a ceramic-matrix composite a technical ceramic forms the matrix and the reinforcement can be fibres, whiskers or particles; continuous-fibre ceramic-matrix composites such as SiC/SiC and C/SiC are described as having densities of 2–3 g/cm3, temperature resistance up to 1600 °C and higher fracture toughness than monolithic ceramics.
- precision note: The density and temperature figures are the review’s general description of continuous-fibre CMCs, not values for any particular material; they are carried in the statement and not published as quantities.
Evidence support: Supported by the cited evidence · one source
Evidence: Bisma 2022 · Peer-reviewed
EstablishedInterphase coatings (pyrolytic carbon or ceramic) control bonding, raise toughness and protect fibres.
In fibre-reinforced ceramics the fibre–matrix interfacial bonding governs load transfer and so fracture toughness, and the fibres are commonly coated with an interphase — typically pyrolytic carbon, or a ceramic such as silicon carbide — to raise toughness and to protect them during processing, although in infiltration routes the coating can also limit how far matrix material penetrates the fibre tows.
Evidence support: Supported by the cited evidence · one source
Evidence: Jon 2020 · Peer-reviewed
EstablishedThermal-expansion mismatch suppresses densification; reinforcement generally kept below 40 vol%.
Because a difference in thermal expansion puts the ceramic matrix around the reinforcement in tension and suppresses densification, the reinforcement in a ceramic-matrix composite is generally kept below 40 per cent by volume.
- precision note: A general practice the review states, not a limit for any particular composite; 40 per cent by volume is an upper bound as the review gives it.
Evidence support: Supported by the cited evidence · one source
Evidence: Bisma 2022 · Peer-reviewed
EstablishedThe reinforcement toughens a brittle ceramic matrix.
In a ceramic-matrix composite the reinforcement’s chief job is toughening: monolithic ceramics have low fracture toughness and are therefore vulnerable to thermal shock, and reinforcing fibres are added to raise toughness while allowing mechanical and thermal properties to be tailored.
- precision note: One premise speaks of ultra-high temperature ceramics and the other of continuous-fibre CMCs generally; both make the toughening role of the reinforcement explicit.
Evidence support: Supported by the cited evidence · 2 sources, multiple sources, independence unknown
Evidence: Jon 2020 · Peer-reviewed; Bisma 2022 · Peer-reviewed