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Synthesis, formation mechanism and hydraulic activity of novel composite cements belonging to the system CaO–Al2O3–ZrO2
This paper describes a new approach for synthesizing novel composite cements belonging to the system CaO–Al 2 O 3 –ZrO 2 via the high-temperature reactions within the Ca 7 ZrAl 6 O 18 –Al 2 O 3 system and characterizes products using X-ray diffraction (XRD), Rietveld XRD quantification, infrared spe...
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| Published in: | Journal of thermal analysis and calorimetry 2017-12, Vol.130 (3), p.1913-1924 |
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| Main Author: | |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
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| Summary: | This paper describes a new approach for synthesizing novel composite cements belonging to the system CaO–Al
2
O
3
–ZrO
2
via the high-temperature reactions within the Ca
7
ZrAl
6
O
18
–Al
2
O
3
system and characterizes products using X-ray diffraction (XRD), Rietveld XRD quantification, infrared spectroscopy, scanning electron microscopy combined with energy-dispersive spectrometry and heat flow calorimetry techniques. Quantitative comparison of the phase transformation in the samples 25 mass% Al
2
O
3
–75 mass% Ca
7
ZrAl
6
O
18
, 50 mass% Al
2
O
3
–50 mass% Ca
7
ZrAl
6
O
18
and 75 mass% Al
2
O
3
–25 mass% Ca
7
ZrAl
6
O
18
sintered in the temperature range 1300–1500 °C was presented. Detailed investigations of the reaction mechanism in the synthesis process in these samples show that calcium zirconium aluminate is unstable when it is heated with alumina, and it undergoes chemical reactions forming calcium aluminates with different CaO/Al
2
O
3
molar ratios and Zr-bearing compounds (CaZrO
3
or ZrO
2
). Probability of liquid-phase sintering of ceramics prepared from alumina and Ca
7
ZrAl
6
O
18
that provides particle rearrangement increases with increasing the CaO/Al
2
O
3
mass ratio of composites. Specifically, this paper discusses composition design and microstructural characterization for achieving modern calcia–alumina–zriconia composite cements. A model that explains the chemical and microstructural changes within the Ca
7
ZrAl
6
O
18
–Al
2
O
3
system due to high temperature was proposed. This study extensively investigates the effects of the cement phase composition on the hydraulic activity in the Ca-aluminates and Zr-bearing compounds containing blended binder pastes.
Graphical Abstract |
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| ISSN: | 1388-6150 1588-2926 |
| DOI: | 10.1007/s10973-017-6498-7 |