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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 248 (1975), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 25 (1990), S. 3191-3198 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Plane silica substrates were coated with a titanium-based deposit by gaseous cementation at temperatures ranging from 600 to 800 ° C, over 1 h to several tens of hours. The cement consisted of hydrogen chloride and titanium. The bilayer structure of the coating was established by X-ray diffraction, X-ray electron microprobe analysis, scanning electron microscopy, low-energy electron-induced X-ray spectroscopy. X-ray photoelectron spectroscopy, optical microscopy and X-ray fluorescence spectroscopy. Thin coatings were amorphous and the composition of the outer zone was close to TiO. Thicker coatings ranging from 2 to 30 μm were crystalline. In this case, the outer layer, designated α-Ti(O) or TiO x with 0.44 ⩽ × ⩾ 0.49, corresponded to an ordered solid solution of oxygen in a close-packed hexagonal titanium. The inner layer in contact with the substrate was Ti5Si3. At fixed temperatures (600, 650, 700, and 800 ° C), the thickness of the coating increased according to a parabolic law. Activation energy and diffusion coefficient were calculated. Thermodynamic considerations concerning the interactions between the gaseous phase of cementation and the silica substrate, are presented from theoretical calculations and from Ti-Si-O phase diagrams experimentally constructed at 800, 1000 and 1300 ° C.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 111 (1937), S. 362-366 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 471 (1980), S. 233-240 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Wirkung chemischer Reduktionsmittel auf die Stabilität von ThiazylringenDie Stabilität von verschiedenen Thiazylhalogeniden wurde untersucht in Gegenwart von Reduktionsmitteln: polare Lösungsmittel und HBr. Die Löslichkeiten von S3N2Cl2 und S6N4Cl2 sind gering. Die polaren Lösungsmittel SOC12, flüss. SO2 und HCOOH sind die besten Lösungsmittel; jedoch können wir zeigen, daß es immer zwischen Thiazylchloriden und dem verwendeten Lösungsmittel eine Wechselwirkung gibt. Die Hauptreaktion erfolgt unter Spaltung des Ausgangsringes und Bildung von S6N42+- oder S4N3+-Ringen.HBr reagiert mit S3N3Cl3. S3N2Cl2 und S6N4C12 unter HCl-Abgabe. S4N3Br wird aus S4N3C1 bei -80°C erhalten; bei höherer Temperatur ist die Reaktion komplexer, und das auf diesem Wege erhaltene S4N3Br ist unrein. Bei den anderen Thiazylchloriden ist die Reaktion bei allen Temperaturen heftig; der Thiazyl-Ring wird gespalten und S4N3Br bzw. S4N3Br3 wird gebildet.Diese Ergebnisse stehen im Einklang mit den unterschiedlichen Stabilitäten der Thiazyl-Ringe. S3N2C12 ist das am wenigsten stabile der Thiazylchloride im Hinblick auf die verschiedenen Parameter (Reaktanden, Druck, Temperatur).
    Notes: The stability of the different thiazyl halogenides was studied in presence of reducing agents: polar solvents and HBr.The solubilities of S3N2CI2 and S6N4CI2 are weak. The polar solvents SOCl2, SO2 liquid and HCOOH are the best solvents, but we have shown there was always interaction between thiazyl chlorides and the solvent used. The main reaction occured with destruction of the initial cycle and formation of the S6N42+ or S4N3+ cycles.HBr reacts on S3N3Cl3, S3N2Cl2 and S6N4CI2 to give substitution reactions with HCI emission. S4N3Br is obtained from S4N3Cl, at -80°C; at higher temperature, the reaction is more complex and S4N3Br obtained by this way is unpure. With the other thiazyl chlorides, the reaction is violent at all temperatures, the thiazyl cycle is destroyed, and S4N3Br or S4N3Br3 is formed.These results are in agreement with the different stabilities of the thiazyl cycles. S3N2Cl2 is the less stable among the thiazyl chlorides towards different parameters (reactants, pressure, temperature).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The molecular vibration frequencies of the gallium-chlorine gaseous species were selected. For the known species Ga2Cl6, GaCl3 and GaCl selection was performed by comparing previous experimental values with our own Raman spectrometric determinations. For the unidentified species Ga2Cl4, Ga2Cl2 and GaCl2 frequency values were evaluated from theoretical literature considerations. The Raman spectra of the vapours obtained by heating condensed gallium and chlorine mixtures are discussed using the selected frequencies and taking into account the Ga2Cl6 and GaCl3 detection limits. With our Raman recording conditions corresponding to well defined spectra, the species are detected up to 5 × 10-3 at. Under these conditions, for Cl/Ga = 3 and between 70 and 500 °C, the main gaseous species are GaCl3 and Ga2Cl6 and the system should be described by the single equilibrium: Ga2Cl6(g)⇌2GaCl3(g). For Cl/Ga = 0.122-3, and between 300 and 800 °C, the representation of the system should be simplified to a single heterogeneous equilibrium between the major species: 2Ga(I)+GaCl3(g)⇌3GaCl(g). In this case, the evolution of the Raman spectra with temperature is explained by taking into account contribution of Ga2Cl4 in very small amounts.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 18 (1987), S. 265-272 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Procedures for the quantitative treatment of Raman spectra are proposed for the investigation of gallium-chlorine gaseous mixtures. They are based on correlations between pressures and Raman band intensities and require a knowledge of reliable entropy and heat capacity data for the main gaseous species. For the ratio Cl/Ga=3 and between 590 and 690 K, the pressure determinations from the band intensity evolution corresponding to the symmetric vibrational modes ‘ν1’ of Ga2Cl6 and GaCl3 confirm the starting consideration of the single equilibrium Ga2Cl6(g)⇌2GaCl3(g). They lead to an enthalpy of dissociation of Ga2Cl6 very close to the literature data. For Cl/Ga3 and between 800 and 950 K, the treatment of the Raman spectra is performed by computation of the GaCl spectrum in order to discriminate between the GaCl3 ‘ν1’ band intensity and the GaCl ‘νs’ branch intensity. This intensity difference and the GaCl ‘νQ’ branch intensity are used for pressure determinations. The results are consistent with the proposed equilibrium 2Ga(l)+GaCl3(g)⇌3GaCl(g). They lead to a calculated reaction enthalpy that allow one to select a reliable value for the enthalpy of formation of GaCl.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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