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

• Published in: Journal of the European Ceramic Society 2021-11, Vol.41 (14), p.7339-7347
• Main Authors: Lu, Gang, Chen, Yisi, Yan, Qingsong, Zhan, Hongxing, Mao, Pu, Liu, Dong
• Format: Article
• Language: English
• Subjects: Carbon fibers; Ceramic cores; Investment casting; SiC; Sintering atmosphere
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2021.07.015

•Csf reinforced silica-based ceramic cores were prepared by injection molding method.•Csf reinforced silica-based ceramic cores were sintered in air and N2 atmosphere.•A significantly enhanced flexural strength of 16.2 MPa is achieved in the ceramic core with 1.5 vol% Csf.•The improved overall performances are attributed to the composite coating on the surface of Csf. Short carbon fiber (Csf) reinforced silica-based ceramic cores for investment casting were prepared by an injection molding approach and sintered in air and N2 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 N2 atmosphere, the peaks in XRD patterns related to the cristobalite increase with an increment in Csf content, which may be attributed to the adhesion interface provided by the Csf and the decreased crystallization free energy. Interestingly, the sample sintered in N2 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 Csf. In addition, the sintering necks can further enhance the interfacial bonding strength between the fibers and ceramic cores matrix.