Al 2 O 3 AlN composite powders were synthesised in N 2 by the carbothermal reductionnitridation method with Al(OH) 3 and different carbon sources (i.e. carbon black, graphite and starch) as starting materials. The effects of the carbon source type, carbon source dosage and reaction temperature on the synthesis performance of the Al 2 O 3 AlN composite powders were investigated. The dried precursors and their synthesised products were characterised by X-ray diffractometer, comprehensive thermal

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... nalysis instrument and scanning electron microscope. The results showed that when the denoted mass ratio of Al 2 O 3 /AlN is 7:3, the optimum conditions for the synthesis of Al 2 O 3 AlN composite powders with carbon black and starch as carbon sources are 1500°C for 2 h and 1600°C for 2 h, respectively. In addition to generating elemental carbon and gaseous H 2 O, the singlephase starch raw material produces gaseous C x H y during heating. The actual mass loss rate generated in the system is consequently significantly higher than the theoretical mass loss rate. The Al 2 O 3 AlN composite powder samples synthesised at 1500°C with carbon black as the carbon source are mainly composed of approximately hedgehog-shaped aggregates, which consist of a mixture of flakes and nearly spherical particles (100300 nm). The powder samples synthesised at 1500°C with graphite as the carbon source form diverse microstructures composed of spherical, flaky and rod-like particles. When starch is used as the carbon source, the encapsulated structure particles formed at 1500°C tend to increase gradually with decreases in the Al 2 O 3 /AlN mass ratio.