Fabrication and microstructure characterization of dense and porous SiC-Si3N4/AlN composites using multi-pass extrusion process

Abstract

Novel dense and porous SiC-Si3N4/AlN composites were fabricated using a multi-pass extrusion process. In the 2nd and 3rd pass dense composites, the diameter of AlN fibers in the SiC-Si3N4 matrix was about 170 μm and 30 μm, respectively. The AlN fibers were refined in the SiC-Si3N4 composites with the increase of extrusion pass number. However, in the porous SiC-Si3N4/AlN composites, the thin layer of AlN was well coated on the continuous pore surface of the porous SiC-Si3N4 matrix. The thickness of the AlN layers in the porous composite was about 40 μm. The detailed microstructures and material properties of the dense and porous SiC-Si3N4/AlN composites were investigated using OM, SEM, XRD, TEM and HRTEM techniques.