The oxidation of SiC particles and its interfacial characteristics in Al-matrix composite

The passive oxidation behavior of SiC particles has been studied in an elec tric furnace at atmospheric pressure and in dry air, the weight change due to the transformation from SiC into SiO2 is descibed as a function of expos ed temperature and holding time. According to the oxidation data of SiC par ticles, the oxidation parameters and the degree of oxidation for SiC partic les can be controlled. Controllable preoxidation of SiC particles is one of the keys for designing interface and interphase to achieve high performanc e aluminum composite. Consequently, the evolution of interfacial reaction p roducts in 2014 aluminum alloy composite reinforced with oxidized-SiC parti cles after extended thermal exposure at elevated temperatures were further characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray diffraction. While it could act to prevent the interfacial reaction between SiC particles and aluminum alloy, the preoxida tion of SiC particles led to the formation of other interfacial reaction pr oducts. The observation of the microstructure revealed that at elevated tem peratures nano-MgO formed initially on the surface of the oxidized SiC part icles and then turned into nano-MgAl2O4 crystal due to the reaction between the SiO2 and aluminum alloy containing Mg. TEM observations indicated that the oxidized layer on SiC particles was uniform and had a good bonding wit h SiC and aluminum alloy. (C) 2001 Kluwer Academic Publishers.