Phase-engineering Strategy of ZrO2 for Enhancing the Mechanical Properties of Porous Cordierite Ceramics

Abstract Porous cordierite ceramics, one of the major industrial materials used in heat transmission pipelines, have gained much attention due to their superior thermal properties. However, the unsatisfactory mechanical properties restrict their further application to some extent. In this work, the porous cordierite ceramics were prepared with fused magnesia, Al2O3, and SiO2 at different sintering temperatures from 1250 ℃ to 1400 ℃. To further reinforce the mechanical properties, ZrO2 characteristic of various phase types was regarded as sintering additives and then the enhancing mechanism was investigated. The phase evolution, microstructures, apparent porosity, bulk density, cold compressive strength, and thermal shock resistance of porous cordierite ceramics have been evaluated. The results indicated a great promotion on the mechanical (from 77.43 to 148.18 MPa) and thermal properties (from1.66 to 2.09 W m-1 K-1) by introducing the sintering additives. Furthermore, the strengthening mechanism of ZrO2 on porous cordierite ceramics was proposed, that is, the monoclinic phases facilitated the substitution reaction of Zr4+ and Mg2+ in cordierite, and the tetragonal phases were highly advantageous for the formation of ZrSiO4. Profiting from the delicate material phase composition modulation of ZrO2, the reinforced porous cordierite ceramics manifests outstanding mechanical properties and superior thermal stability.