Microstructure Changes of Beta Alumina Sintering at Lower Temperature

Abstract

Changes in the microstructure and phase content of beta alumina near the lowest possible β-Al2O3 to β-Al2O3 transform temperature were investigated through varying sintering temperature. Obvious microstructure varieties were observed in stabilized β/β alumina specimens following extended sintering treatments. The results show that there is a slightly lower temperature of 1150°C for nanometer precursor powder particles to transform into grains and for β-Al2O3 to convert into β-Al2O3.

Improving the Reactivity and Stability of Fe2O3/Al2O3 in Chemical Looping Process by Optimizing the Al2O3 Precursor

“…It can also be found in Figure3and Table2that high CO 2 purity was maintained for the Fe 2 O 3 -activated Al 2 O 3 and Fe 2 O 3 −AlOOH although a nearly 50% decrease occurred in their BET surface area, and the surface area was still much higher than that of the fresh Fe 2 O 3 and Fe 2 O 3 -inert Al 2 O 3 . Al 2 O 3 with different crystal phases and textures can be synthesized from Al(OH) 3 or AlOOH via different calcination programs; however, compared to other transition phases, α-Al 2 O 3 as the most stable one usually possesses fewer pore surfaces and volumes because of the deformation during calcination at high temperature,37 which may be one reason for the decaying texture of Al 2 O 3 -supported OCs by correlating the Table2with Figure4. Moreover, a correlation analysis between the activity and structure of the OCs was conducted.…”