The enhanced mechanical properties of SiC nanowires/Ba0.75Sr0.25Al2Si2O8 ceramics with embedded SiO2 interface

Abstract

In this work, low-softening-temperature and low-modulus SiO2 was introduced as an embedded interface between SiC nanowires (SiCnws) and a BaxSr1−xAl2Si2O8 ceramic matrix to enhance strength and toughness of the ceramic. During the sintering process, molten SiO2 enhances the flowability of the ceramic powders and modifies the dispersion of SiCnws. The strengthening effect of SiCnws was fully realized, and the flexural strength of the optimized ceramics reached 193±16 MPa, which represents an increase of 52.6%. After the formation of the embedded SiO2 interface with a low modulus, cracks can deflect along the SiCnws surface, which is consistent with the criterion of He and Hutchinson. This can effectively extend the crack propagation path, and the fracture toughness (KIC) is thus improved by 94.0%, reaching 3.1±0.5 MPa·m1/2.

Keywords

• multiphase ceramics
• sio2 interface
• densification
• mechanical properties