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Tridymite

About: Tridymite is a research topic. Over the lifetime, 840 publications have been published within this topic receiving 14831 citations.


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Journal ArticleDOI
TL;DR: In this paper , the crystal transformation of silica in coal and biomass combustion processes was investigated and detailed transformation pathways of crystalline silica for the first time, showing that amorphous silica can transform into tridymite and cristobalite starting at 1000 °C.

6 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of water vapour pressure at high temperature (1200°C) on the corrosion of hot-pressed silicon nitride (HPSN) doped with Al 2 O 3 -MgO was evaluated.
Abstract: Silicon nitride is particularly sensitive to high-temperature oxidation. The intensity of oxidation is influenced by the chemical composition of the amorphous phases present at the grain boundaries and consequently by the sintering additives responsible for their formation. The presence of water vapour increases Si 3 N 4 oxidation also in intermediate temperature conditions. In this study the influence of water vapour pressure at high temperature (1200°C) on the corrosion of hot-pressed silicon nitride (HPSN) doped with Al 2 O 3 -MgO was evaluated. The water vapour has a great influence on the devitrification of the amorphous oxide upper layer, due to the formation of crystalline oxides (primarily cristobalite and tridymite). This process increases the oxidation rate, consequently increasing the porosity of the exposed surface. The microstructural evolution of HPSN in the presence of water vapour at 1200°C was analysed by SEM and XRD.

6 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of sintering temperature and amount of CP on samples proprieties were investigated and it was observed that X-ray diffracion measurements confirmed that EQS was transformed into cristobalite and tridymite phases when both Sintering Temperature and holding time were increased.
Abstract: This work addresses the development of an eventual low cost ceramic insulating or microfiltration membrane supports from inexpensive raw materials such Eloued quartz sand (EQS) and calcium phosphate (CP) using uniaxially dry compaction method. The prepared samples were sintered at different temperatures ranging between 1200 and 1550 oC. Subsequently, the effects of sintering temperature and amount of CP on samples proprieties were investigated. It is observed that X-ray diffracion measurements confirmed that EQS was transformed into cristobalite and tridymite phases when both sintering temperature and holding time were increased. This transformation is favored with increasing amount of CP, it is observed also formation of CaSiO3 and Ca(Fe)(Al)PO4. The SEM images of the samples sintered at different temperatures illustrate that silica grains, CP grains, intergranular phase contents (Si, Ca, P, and O) and an important open porosity depend on the sintering temperature. The porosity ratio changes in the range between 37% and 34% according to sintering temperature and to CP content; these values are in good agreement with SEM images. The thermal expansion behavior shows a weak expansion in the range of temperature between 600 and 1000 oC which is situated between 1.27% and 1.33% (variation of 0.05% at 400 oC).

6 citations

Journal ArticleDOI
15 Oct 1983-Lithos
TL;DR: In this article, the phase diagram of the alkali feldspars was analyzed and it was shown that the Al/Si disordered structure was produced during growth and afterwards transformed into a triclinic structure with cross-hatched twinning.

6 citations

Journal Article

6 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202315
202231
202125
202027
201920
201826