ZrB2/Al2O3 composite powders prepared by self-propagating high-temperature synthesis
(Department of Material Science, Fudan University, Shanghai 200433, China)
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