Synthesis of β-SiAlON/h-BN nanocomposite by a precursor infiltration and pyrolysis (PIP) route

• β-SiAlON/h-BN nanocomposite was fabricated by a novel PIP combining pressureless sintering route.
• The formed nanoflake-like h-BN particles with width of 1–2 μm and thickness of 50–200 nm were distributed homogeneously in the composite, and were inclined to exist in the β-SiAlON grain boundaries.
• The obtained nanocomposite exhibited good strength, excellent machinability and improved thermal shock resistance, and can be applicable for engineering.

β-SiAlON/hexagonal boron nitride (h-BN) nanocomposite was successfully fabricated by a precursor infiltration and pyrolysis (PIP) route using boric acid and urea as precursors of h-BN, and the composite was pressureless sintered at 1750 °C in nitrogen. XRD and XPS results confirmed that the composite was composed of β-SiAlON and h-BN phases. Microstructure observation showed that the nanoflake-like h-BN particles with width of 1–2 μm and thickness of 50–200 nm were formed and distributed homogeneously in the composite. The nanoflake-like h-BN particles were inclined to exist in the β-SiAlON grain boundaries. The machinability and thermal shock resistance were improved due to the formation of h-BN in β-SiAlON matrix.

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