Investigation of microstructure and properties in short carbon fiber reinforced silica-based ceramic cores via atmosphere sintering.

• C sf reinforced silica-based ceramic cores were prepared by injection molding method. • C sf reinforced silica-based ceramic cores were sintered in air and N 2 atmosphere. • A significantly enhanced flexural strength of 16.2 MPa is achieved in the ceramic core with 1.5 vol% C sf. • The improved overall performances are attributed to the composite coating on the surface of C sf. Short carbon fiber (C sf) reinforced silica-based ceramic cores for investment casting were prepared by an injection molding approach and sintered in air and N 2 atmospheres, respectively. SEM and XRD results present that there are some in-situ formed silicon carbides (SiC) in sintered samples. Moreover, as for the ceramic cores sintered in N 2 atmosphere, the peaks in XRD patterns related to the cristobalite increase with an increment in C sf content, which may be attributed to the adhesion interface provided by the C sf and the decreased crystallization free energy. Interestingly, the sample sintered in N 2 exhibits a higher flexural strength about 16.2 MPa, which is 155 % times than that of the samples sintered in air. This is originated from an obvious composite coating consisting of fused silica, SiC and cristobalite on the C sf. In addition, the sintering necks can further enhance the interfacial bonding strength between the fibers and ceramic cores matrix. [ABSTRACT FROM AUTHOR]