Preparation of SiC/Si3N4 composites with rod-like microstructure by combustion synthesis

SiC/Si3N4 composites with rod-like microstructure were successfully prepared from a mixture of Dy2O3, amorphous carbon (carbon black) and Si powder in static N2 atmosphere using combustion synthesis (CS) in combination with a controlled pre-reaction mechanical activation treatment. The results showed that a large number of crystals with rod-like microstructure which were made of SiC and Si3N4 appeared in the product. The present work demonstrated that Dy2O3 is a good additive for the preparation of SiC/Si3N4 composites with rod-like microstructure, and the pressure of N2 is also an important factor.

A large amount of β-Si3N4 and β-SiC is detected. They are both the major phases of the products.The powder consist predominantly of rod-like crystals with aspect ratio close to 5 and the cross-section of them appear clearly hexagonal.Figure optionsDownload as PowerPoint slideHighlights
► SiC/Si3N4 composites with rod-like microstructure were successfully prepared.
► Dy2O3 is a good additive for the preparation.
► The pressure of N2 is an important factor for the preparation.