Synthesis and properties of CaAl{sub 2}O{sub 4}-coated Al{sub 2}O{sub 3} microcomposite powders
- Univ. of Illinois, Urbana, IL (United States)
Novel microcomposite powders, consisting of inert cores ({alpha}-Al{sub 2}O{sub 3}) surrounded by reactive cement-based coatings (CaAl{sub 2}O{sub 4}), were synthesized by a modified Pechini process. The evolution of the crystalline CaAl{sub 2}O{sub 4} phase during calcination was studied using multiple analytical techniques, including DRIFTS, {sup 13}C and {sup 27}Al MAS FT-NMR, and XRD, for both pure CaAl{sub 2}O{sub 4} and CaAl{sub 2}O{sub 4}-coated Al{sub 2}O{sub 3} precursor powders. In both powders, decomposition proceeded via hydrocarbon chain scission and removal of ester groups at low temperatures (T {le} 450 C), followed by the formation of inorganic carbonates at higher temperatures (T {ge} 450 C). These decomposition processes were accelerated by the underlying Al{sub 2}O{sub 3} cores. Transmission electron microscopy (TEM) of the fully calcined powders showed that the inert {alpha}-Al{sub 2}O{sub 3} particles were surrounded by relatively uniform CaAl{sub 2}O{sub 4} coatings ranging in thickness from approximately 10 to 100 nm.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-91ER45439
- OSTI ID:
- 136490
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 11 Vol. 78; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
Similar Records
Rate of reactions between D/sub 2/O dand Ca/sub x/Al/sub y/O/sub z/
Hydrothermal transformation of the calcium aluminum oxide hydrates CaAl{sub 2}O{sub 4}.10H{sub 2}O and Ca{sub 2}Al{sub 2}O{sub 5}.8H{sub 2}O to Ca{sub 3}Al{sub 2}(OH){sub 12} investigated by in situ synchrotron X-ray powder diffraction