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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
01 Feb 2001
TL;DR: In this article, a reusable PTC composite material which has a low room-temperature resistivity, a transition temperature of <200 deg.C, and a high heat resistance was proposed.
Abstract: PROBLEM TO BE SOLVED: To provide a reusable PTC composite material which has a low room- temperature resistivity, a transition temperature of <200 deg.C, and a high heat resistance and causes large resistivity jumping at the transition temperature and a low power loss. SOLUTION: This PTC composite material contains; (i) a matrix of a ceramic material having either one of a cristobalite crystal structure to which with the oxide of at least element selected from among Be, B, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, and W and a tridymite crystal structure, and (ii) a conductive phase containing at least one kind of metal, silicide, nitride, carbide, or boride and scattered through the matrix.

19 citations

Journal ArticleDOI
TL;DR: In this paper, a powder technology route was reported as a low cost, simple and safe method for the fabrication of SiO2 NPs, which has high throughput (91.7%) for different applications.

19 citations

Journal ArticleDOI
TL;DR: In this article, Wiederhorn et al. discuss the properties of high strength properties of glass and propose a method to measure the surface energy of a glass crystal in the Fatigue range.
Abstract: terials,” Am. Scicntist, 53 [ 11 20-51 (1965). 6 (a) A. A. Gritlith, “Phenomena of Rupture and Flow in Solids,” Phil. Trans. Roy. SOC. (London), 221A, 163-98 (1920). (a) A. A. Gritlith, “Theory of Rupture,” Proc. First Intern. Congr. Appl. Mechanics, Delft, pp. 55-63 (1924). ‘ S . M. Wiederhorn; pp. 503-28 in Materials Science Research, Vol. 3. Edited by W. W. Kriegel and Hayne Palmour 111. Plenum Press. New York, 1966. S. M. Wiederhorn; pp. 293317 in Environment-Sensitive Mechanical Behavior of Materials. Edited by A. R. C. Westwood and N. S. Sto?yff. Gordon and Breach, New York, 1966. I . J. Gilman, Direct Measurements of Surface Energies of Crystals,” J. Appl. Phys., 31 1121 2208-18 (1960). E. B. Shand, “Fracture Velocity and Fracture Energy of Glass in the Fatigue Range,” J. Am. Cerum. Soc., 44 [l] 21-26 (1961). lo R. J. Charles and W. B. Hillig; pp. 511-27 in Symposium on Mechanical Strength of Glass and Ways of Improving It. Florence, Italy, September 25-29, 1961. Union Scientiftque Continentale du Verre, Charleroi, Belgium, 1962. l1 W. B. Hillig and R. J. Charles, pp. 682-705 in High-Strength Materials. Edited by V. F. Zackey. John Wiley & Sons Inc., New York, 1965. Samuel Glasstone, K. J. Laidler, and Henry Eyring, Theory of Rate Processes, p. 369. McGraw-Hill Book Co., New York, 1941. Samuel Glasstone, Textbook of Physical Chemistry, 2d ed.; p. 1201. D. Van Nostrand Co.. Inc., New York, 1946. 1.R. B. Bud, W. E. Stewart, and E. N. Lightfoot, Transport Phenomena; pp. 519, 529. John Wiley & Sons, Inc., New York, 1960. 16 J. M. Coulson and J. F. Richardson, Chemical Engineering, Vol. I , p. 236. McGraw-Hill Book Co., New York, 1955. 16Handbook of Chemistry and Physics, 47th ed.; p. 646. Chemical Rubber Publishing Co., Cleveland, Ohio, 1966.

19 citations

Journal ArticleDOI
TL;DR: In this paper, a series of nominal compositions Al1−xFexPO4 with 0≤x≤0.8 calcined at various temperatures have been synthesized by the co-precipitation method.

19 citations

Journal ArticleDOI
TL;DR: In this article, the experimental Raman spectra of monoclinic tridymite and its higher temperature orthorhombic modification were successfully simulated with valence force fields applied to the X-ray determined structural parameters.
Abstract: The experimental Raman spectra of monoclinic tridymite and its higher temperature orthorhombic modification were successfully simulated with valence force fields applied to the X-ray determined structural parameters. The normal modes contributing to the corresponding Raman peaks in both the phases share essentially the same types of atomic displacements or bond deformations. In the modes with the wave numbers between 100 and 600 cm−1, predominant are the librations of Si-O-Si planes around Si-Si lines, being followed by bending of Si-O-Si or O-Si-O angles. The librational motions of SiO4 units around Si appear in the modes below 100 cm−1. Significant bond stretching and compression appear in the modes with wave numbers higher than 700 cm−1: the deformations are classified into 10 types, 7 for Si-O-Si and 3 for SiO4. Some modes in the highest frequency group between 1150 and 1250 cm−1 show symmetric bond stretching and compression of SiO4 units, while those between 1000 and 1150 cm−1 antisymmetric stretching and compression of Si-O-Si. A low-frequency normal mode is identified to have the polarization vectors of O atoms, which are nearly parallel with the largest principal axes of their thermal ellipsoids. A disorder model is presented to account for the extremely large mean square displacements of O atoms, and a possibility is suggested for the normal mode to boost the hopping of the SiO4 units between the two orientations.

19 citations


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