Abstract: Self-propagating high-temperature synthesis(SHS) method was used to synthesize ZrB2/Al2O3 composite powders from B₂O₃-ZrO₂-Al system. X-ray diffractometry(XRD) and scanning electron microscopy(SEM) analyses show the presence of ZrB₂ and Al₂O₃ as the primary phases in the composite powders, while the presence of a very small amount of ZrO₂ is thought to be unreacted zirconium oxide. Transmission electron microscopy(TEM) and high resolution electron microscopy(HREM) observations of microstructure of the composite powders indicate that the interfaces of ZrB₂/Al₂O₃ bond well without any interfacial reaction products. It is proposed that the good interfacial bonding of composite powders results from the ZrB₂ particles crystallizing and growing on the Al₂O₃ particles surface with surface defects acting as nucleation centers.

Key words: self-propagating high-temperature synthesis; zirconium diboride; composite powder; B₂O₃+ZrO₂+Al system; microstructure