Fracture strength of ZrO2/SiC hybrid tubular honeycomb ceramic filters

The fracture strength of commercial ZrO 2 /SiC hybrid ceramic filters with a tubular honeycomb shape was assessed using uniaxial compression tests combined with Weibull statistical analysis of failure stresses, discriminating the individual contributions from the SiC support and the ZrO 2 membrane. First, it is shown that these filters possess high mechanical integrity ( i.e. , characteristic strength ( ) of 81.2 MPa) and reliability ( i.e. , Weibull modulus ( m ) of 10.1), outperforming the standard bare SiC support ( = 68.3 MPa and m = 9.8). Second, it is shown that the sintering cycle of the ZrO 2 membrane in air significantly strengthens the filter (by ∼26.1 MPa compared to the standard support; = 94.4 MPa), attributed to passivation of the SiC support, which improves the cohesion of the macroporous skeleton making it tougher. In contrast, the ZrO 2 membrane itself weakens the filter (by ∼13.2 MPa relative to the passivated support) due to thermoelastic mismatch between ZrO 2 and SiC, which generates residual tensile stresses. Third, comparison between ZrO 2 /SiC hybrid filters and SiC non-hybrid filters reveals that the latter are ∼51% stronger ( = 81.2 MPa vs. 122.3 MPa), which underscores the critical influence of the air-firing conditions and the membrane-to-support relationships. Finally, aspects beyond mechanical strength—such as production costs and filtration performance—are discussed to guide the selection of ceramic filters for practical filtration applications.