Thermal Expansion of Cordierite

Fabrication of Nitrogen‐Containing Cordierite Ceramics

“…Although the microscopic features of the cordierite sinters differed, their relative densities were similar, which indicates that the densification of cordierite can be achieved by hot pressing at an applied pressure of 15 MPa. It was found that the coefficient of thermal expansion of nitrogen‐containing cordierite ceramics fabricated in the present study was remarkably low, and it was comparable with the reported values for oxide cordierite ceramics 7,8,10,38,39 . This finding suggests that a small amount of nitrogen (several mass percent) does not negatively affect the CTE, although the chemical state of nitrogen in cordierite‐based oxynitride ceramics is unknown.…”

“…I t is well known that cordierite has three polymorphs: a high‐temperature‐stable α‐form (hexagonal, P 6/ mcc ), a low‐temperature‐stable β‐form (orthorhombic, Cmcc ), and a metastable μ‐form (hexagonal, P 6 2 22) 1–6 . Only polycrystalline α‐cordierite ceramic has a remarkably low coefficient of thermal expansion (CTE) because of the counterbalancing of thermal expansion of the constituent α‐cordierite (Mg 2 Al 4 Si 5 O 18 ) crystals, which have a positive expansion along the a ‐axis and a negative expansion along the c‐axis 7,8 . Accordingly, α‐cordierite ceramics are used in a wide variety of applications, such as apparatuses for ceramic sintering, insulators for high current, and carriers of catalytic converters that can be constantly exposed to a rapidly heating and cooling atmosphere.…”

Elaboration and chemical corrosion resistance of tubular macro-porous cordierite ceramic membrane supports

“…This uniqueness of cordierite is caused by the negative lattice expansion coefficient in the c-axis direction, which provides excellent resistance to thermal shock as well as low thermal conductivity [16][17][18]. This makes it suitable to be applied where the environmental temperature is rapidly and severely changed such as refractory products for industrial furnaces and electric heaters [19], heat exchangers for gas turbines, thermal shock-resistant tableware, and monolithic catalyst supports for diesel automobiles [20][21][22][23].…”

Fabrication and Characterization of Near‐Net‐Shape In Situ Reaction‐Bonded Porous Cordierite/SiC Ceramics

“…Therefore, cordierite‐based materials are extensively used in the fields where the environmental temperature is rapidly and severely changed. Some examples of the applications are refractory products, such as kiln furniture, refractory‐lined chambers, and gas burners for industrial furnaces, heat exchangers for gas turbines engines, catalyst carriers, etc . The low intrinsic strength of cordierite can be compensated by the presence of secondary phases such as mullite, zircon, and SiC .…”