Due to their excellent thermal and mechanical properties silicon‐based ceramics and composites are prime candidates for high temperature structural applications. In this communication the authors report for the first time that amorphous silicoaluminum carbonitride (SiAlCN) ceramics possess anomalously high resistance to oxidation and hot‐corrosion. A mechanism underlying the observed phenomena is discussed.

To reduce the cost of nanocomposites and improve the dispersion of nanoparticles, Al2O3np/SiCnp/Al hybrid nanocomposites are fabricated by combining liquid-state blowing and ultrasonic-assisted casting. The average grain size of the matrix decreases to 39 μm in Al2O3np/SiCnp/Al, which shows improvements of approximately 118% and 26% as compared to those of Al2O3np/Al and SiCnp/Al, respectively. X-ray Diffractometer (XRD) results confirm the presence of SiCnp and Al2O3np in hybrid nanocomposites. The dispersed SiCnp and Al2O3np are homogeneously distributed in the matrix and no clusters consisting of SiCnp and Al2O3np exist in the microstructure. Theoretical analyses also verify that there is little possibility for clusters to form in the melt. Good bonding between nanoparticles and Al is demonstrated. Neither cavities nor reaction products exist at the interface. The ductility and the strength of Al2O3np/SiCnp/Al are improved. The improvement in yield strength of Al2O3np/SiCnp/Al, in comparison with that of A356, is about 45%.

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