Thermal expansion effects in cordierite. Final report, March 16, 1981-March 15, 1984

A Huber-Guinier x-ray diffraction system was modified for accurate expansion work. Lattice thermal expansion data were obtained on cordierite samples doped with Li/sup +1/, Be/sup +2/, B/sup +3/, P/sup +5/, Ca/sup +2/, Zn/sup +2/, Ge/sup +4/ at the 1% and 5% level. The a-axis thermal expansion was mostly linear with temperature and relatively insensitive to dopant type and level. The c-axis thermal expansion showed marked nonlinearities and trend reversals with temperature and dopant level. No obvious correlations were found between the expansion data and either ion size charge or the room temperature lattice parameters. The largest decrease in overall c-axis thermal expansion was shown by Li/sup +1/ at the 5% level and the largest initial decrease in c-axis expansion by Ca/sup +2/ at the 1% level.