Fabrication and properties of SiC_nw‐reinforced SiC composites by reactive melt infiltration with BN and PyC interface

Abstract

To tailor the fiber-matrix interface of SiC nanowires-reinforced SiC (SiC nw /SiC) ceramic matrix composites (CMCs) for improved mechanical properties, SiC nanowires were coated with BN and pyrolytic carbon (PyC) compound coatings prepared by the dip-coating process in boric acid and urea solution and the pyrolysis of phenolic resin. SiC nw /SiC CMC with PyC/BN interfaces were fabricated by reactive melt infiltration (RMI) at 1680 • C for 1 h. The influences of phenolic resin content on the microstructure and mechanical properties of the CMC were investigated. The results showed that the flexural strength and fracture toughness reach the maximum values of 294 MPa and 4.74 MPa m 1/2 as the phenolic resin content was 16 and 12 wt%, respectively. The displacement-load curve of the sample exhibited a gradient drop with increasing phenolic resin content up to 12 wt%. The results demonstrated that the PyC/BN compound coatings could play the role of protecting the SiC nw from degradation as well as improving the more moderate interfacial bonding strengths during the RMI.