Effect of transition-metal-ion doping on high temperature thermal expansion of 3:2 mullite—An in situ, high temperature, synchrotron diffraction study

摘要: Abstract The effect of Ti 4+ , Cr 3+ or Ga doping on thermal expansion 3:2 mullite was examined from 20 °C to 1400 °C by high temperature XRD using synchrotron radiation. room lattice expanded with metal-ion incorporation and the change in b -axis larger than that along a (Δ  > Δ ) for all ion types. Upon heating, largest elongation / RT similar pure (∼0.5%). Least observed (0.28% ≤ Δ  ≤ 0.41%). not constant range 1400 °C, had linear dependence ( α T ) =  A 0  +  1 Δ ). mean values increased (20 °C ≤   ≤ 1000 °C), but were always within 3.0–6.7. decreased anisotropy expansion, however, showed sharp increase. Trends associated type quantity dopant are discussed.