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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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Patent
22 May 1985
TL;DR: In this article, a boat is roughened by sand blast with powder of SiC, Al2O3 or the like, and then the boat is dried and heated at about 380-1,450 deg.C for >= about 1hr in an electric furnace to form a tridymite layer to such a degree that quartz is not exposed to the surface.
Abstract: PURPOSE:To grow a large-sized single crystal in high yield when a single crystal of an inorg. cmpound is grown from a group IIIb element and a group Vb element in the periodic table by a boat growing method, by using a quartz boat after forming a tridymite layer on the surface and roughening the inside. CONSTITUTION:A quartz boat is roughened by sand blast with powder of SiC, Al2O3 or the like. After cleaning the surface by pickling and washing, the boat is dried and heated at about 380-1,450 deg.C for >= about 1hr in an electric furnace to form a tridymite layer to such a degree that quartz is not exposed to the surface. A single crystal of a group III-V compound is manufactured by using the resulting boat.

1 citations

Journal ArticleDOI
TL;DR: In this article, structural models related to the stuffed tridymite derivative structures are proposed for the new forms of the ferri-aluminate, and two original phases, denoted O1 and O2, are obtained; they are metrically similar (3A× 3 A×C and β≈90°) and only differ by their space groups.

1 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the selectivity of the structure-directing action of amines under vapor-phase crystallization conditions basically corresponds to the template hydrothermal synthesis.
Abstract: Transformations of granules based on kaolin and phosphoric acid under conditions of vapor-phase crystallization in a mixture of water vapor and a structure-directing agent have been studied. It has been shown that silicoaluminophosphate granules obtained in the presence of dipropylamine, triethylamine, or tetramethylammonium hydroxide as a structure-directing agent consist of a shell formed by dense nonporous cristobalite, tridymite, and berlinite phases and the core made mainly of microporous crystalline silicoaluminophosphates. The formation of the shell, which ensures the strength of the silicoaluminophosphate granules, is due to the interaction of steam with the material of the granules at the initial stages of vapor-phase crystallization. It has been established that the selectivity of the structure-directing action of the amines under vapor-phase crystallization conditions basically corresponds to the template hydrothermal synthesis. It has been assumed that the specific features of the structure-directing action of dimethylamine during vapor-phase transport synthesis are due to its low boiling point, which ensures the primary contact of the granules with template, rather than water molecules. As a result, the products of the transformation of granules in the presence of a mixture of dimethylamine and water do not contain dense nonporous phases and are cocrystallized silicoaluminophosphate and calcium aluminosilicate with the gismondine structure.

1 citations

Patent
10 Apr 2015
TL;DR: In this article, a model block is coated with a ceramic suspension in layers with subsequent sprinkling with a heat resistant material and drying of each layer Sprinkling material is ground crushed ceramic shells containing quartz in phases of tridymite and cristobalite, iron and iron scale.
Abstract: FIELD: technological processesSUBSTANCE: invention relates to foundry A model block is coated with a ceramic suspension in layers with subsequent sprinkling with a heat resistant material and drying of each layer Sprinkling material is ground crushed ceramic shells containing quartz in phases of tridymite and cristobalite, iron and iron scaleEFFECT: invention provides for improved crack resistance and strength of ceramic shells1 ex

1 citations

Journal ArticleDOI
TL;DR: In this article, phase equilibria of the PbO-FeO-SiO2 and PbBO-CaO -SiO 2 slags with liquid Pb metal, solid or liquid Fe metal and solid oxides were investigated at 1100-1689°C.
Abstract: Phase equilibria of the PbO-“FeO”-SiO2 and PbO-“FeO”-CaO-SiO2 slags with liquid Pb metal, solid or liquid Fe metal and solid oxides [cristobalite and tridymite SiO2, wustite (Fe,Ca)O1+x, olivine (Fe,Ca)2SiO4, dicalcium silicate (Ca,Fe)2SiO4, wollastonite (Ca,Fe)SiO3 and lime (Ca,Fe)O] were investigated at 1100-1689 °C. These conditions correspond to the minimum solubility of PbO in slag in presence of Pb and Fe metals at reducing conditions and represent the limit of lead smelting and slag cleaning process. High-temperature equilibration on silica or iron foil substrates, followed by quenching and direct measurement of Pb, Fe, Ca, and Si concentrations in the phases with the electron probe x-ray microanalysis (EPMA) was used to accurately characterize the system. Present results provide important basis for improvement of the thermodynamic models for all phases in this system.

1 citations


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