High‐Thermal‐Expansion Polycrystalline Leucite Ceramic

A high‐thermal‐expansion ceramic consisting of leucite crystals was prepared by sintering leucite powder. The densification was promoted by adding Li 2 CO 3 or Na 2 CO 3 . The leucite ceramic obtained had a thermal expansion coefficient of about 2.4 × 10 −5 /°C from room temperature to 600°C. Some of the Li + and Na + ions were incorporated into the leucite crystal lattice to form solid solutions, and the characteristic tetragonal‐cubic inversion point shifted from ca. 600° to 650°C.