Polymer-Derived Al2O3-SiC Nanocomposites: Preparation Route vs. Microstructure

摘要: A polycarbosilane-based SiC-precursor with high ceramic yield (75 % by weight) was used for preparation of Al2O3-SiC nanocomposites. Two different ways the composite were tested. First, pre-sintered alumina matrix vacuum infiltrated liquid precursor. Second, alpha-alumina powder coated polymer diluted in cyclohexane, solvent evaporated, and axially pressed at elevated temperature (350 degrees C) 50 MPa pressure (warm pressing). The specimens then heat treated under carefully controlled conditions inert atmosphere (Ar), order to facilitate ceramisation precursor outgasing pyrolysis products from composite. either sintered or hot-pressed, attain complete densification. influence processing parameters (way preparation, concentration polymer, sintering/hot-pressing) on microstructure (grain size grain distribution Of Al2O3 grains SiC particles, fraction inter- intragranular presence defects) is discussed implications composites' way preparation.