The dispersion processing of SiC whisker and particle and themechanical properties of SiC particle and/or whisker reinforced AlzO3composites were studied. With electrostatic repulsion and stericinteraction methods, SiC whisker and particle were dispersedhomogeneously in Al2O3 matrix and the flexure strength and fracturetoughness of hot pressed SiCw-Al2O3 composite were up to 836 MPa and8.1 MPa.m~1/2, respectively. The hot-pressed SiC-Al2O3 compositeswere futher Nz- HIP post-treated. The fiexural strength of N2-HIPpost-treated SiC-Al2O3 composite was improved about 37-46 and theflexural strength of 1030 MPa was obtained. SEM and XRD analysisindicated that the nitnding reaction took place only on the surfaceof samples and the microstructure was improved. The grain size ofsurface reaction layer changed from about 2.0 pin to 0.5 mu mFinally, the strengthening mechanisms of the Nz-HIP post-treatmentwere discussed.
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