Crystal Structures and Mechanism of Thermal Expansion of High Cordierite and Its Solid Solutions

Abstract

The crystal structure of high cordierite and that of high cordierite solid solutions containing either Mn or Ga or Ge were refined. The structural changes caused by substitutions and the characteristic features of deformations of each T1O 4 , T2O 4 tetrahedron and MO 6 octahedron were clarified. Thorough crystal chemical considerations led to a conclusion that the structure of Mn‐bearing solid solution at room temperature may be regarded as a model structure of high cordierite at an elevated temperature. On the basis of the thermal expansion mechanism derived from this consideration, the thermal expansion behavior of the solid solutions is presented.