Accession Number : AD0484613

Title :   THERMODYNAMIC AND KINETIC STUDIES OF BORIDES AND OTHER REFRACTORY MATERIALS AT HIGH TEMPERATURES.

Descriptive Note : Yearly summary technical rept. no. 2, 1 Jan-31 Dec 65,

Corporate Author : RICE UNIV HOUSTON TX DEPT OF CHEMISTRY

Personal Author(s) : Margrave, John L.

Report Date : MAY 1966

Pagination or Media Count : 41

Abstract : The reactions of elementary fluorine with several refractory elements (B, C, Si, Zr and Ir) and with several refractory compounds (TiC, TiB2, WC and W2B5) have been quantitatively observed and rate equations derived. The products of fluorination have isolated and studied to provide further information. For example, solid CF(x), the reaction product between graphite and F2 at low temperatures, has been thermally decomposed and the products characterized by gas chromatography and mass spectrometry. The high temperature drop calorimeter has been remodeled and is now capable of operation at temperatures up to 2000 K with the samples being contained in a refractory metal capsule (Ir, Ta or Mo) and heated inductively. Measurements up to the highest temperatures on the easily oxidized borides and carbides have not yet been made because of problems in obtaining capsules which can be tightly sealed. Several designs have been investigated. With a Pt-Rh alloy, one can approach 1500 C and several studies have been carried out. Gold capsules are being used for collection of data up to 1000 C and the measurements will be extended when the capsules are available. Fluorine bomb calorimetry is being applied for determination of heat of formation of refractory borides and oxides. (Author)

Descriptors :   *BORIDES), (*REFRACTORY MATERIALS, (*THERMODYNAMICS, REFRACTORY METAL ALLOYS), HIGH TEMPERATURE, GRAPHITE, FLUORINE, OXIDES, EXPERIMENTAL DATA, CALORIMETRY, GAS CHROMATOGRAPHY, CARBIDES, HEAT OF FORMATION, MASS SPECTROSCOPY, ZIRCONIUM, TITANIUM, REACTION KINETICS, TUNGSTEN, DECOMPOSITION, GOLD.

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE