High temperature single crystal properties of mullite

摘要: Abstract Extensive neutron diffraction and Rietveld studies of dense, hot pressed mullite (3Al 2 O 3 ·2SiO ) have been conducted up to 1650 °C in air, yielding a complete set lattice parameters axial thermal expansion coefficients. Unconstrained powders the same stoichiometric composition were also analyzed by X-ray techniques 900 °C from which coefficients obtained. An earlier reported structural discontinuity was confirmed XRD lie temperature range 425 450 °C. Single-crystalline fibers 2·5Al ·SiO grown melt laser-heated, float zone method. A partial single-crystal elastic moduli determined various sections fiber, Brillouin spectroscopy, room 1400 °C. They indicated roughly 10% reduction stiffness over that range.