ZrB_2/Al_2O_3 composite powders prepared by self-propagating high-temperature synthesis

摘要

Self-propagating high-temperature synthesis(SHS) method was used to synthesize ZrB_2/Al_2O_3 composite powders from B_2O_3-ZrO_2-Al system. X-ray diffractometry(XRD) and scanning electron microscopy (SEM) analyses show the presence of ZrB_2 and Al_2 O_3 as the primary phases in the composite powders, while the presence of a very small amount of ZrO_2 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 ZrB_2 /Al_2O_3 bond well without any interfacial reaction products. It is proposed that the good inter-facial bonding of composite powders results from the ZrBz particles crystallizing and growing on the Al_2 O_3 particles surface with surface defects acting as nucleation centers.