Accession Number : AD0450678


Title :   MASS SPECTROMETRIC STUDY OF ZIRCONIUM DIBORIDE


Corporate Author : UNION CARBIDE RESEARCH INST TARRYTOWN NY


Personal Author(s) : Trulson, O C ; Goldstein, H W


Report Date : Oct 1964


Pagination or Media Count : 20


Abstract : A mass spectrometer was used with a high temperature Knudsen effusion source to obtain vapor pressure data for zirconium diboride in the temperature range 2267 to 2445 K. The heat of vaporization at 298 K determined from a Third Law analysis of the data is 454.5 = 5.3 kcal/mole. Vapor pressure data from zirconium and boron were also obtained. The Third-Law heats of vaporization are 141.8 = 3.3 kcal/ mole for zirconium and 130.3 = 3.3 kcal/mole for boron. The corresponding heat of formation of zirconium diboride at 298 K is -72.1 kcal/ mole. Separate vapor-pressure measurements made on ZrB2 mixed with C in a graphite crucible gave a value of -74.5 kcal/mole.


Descriptors :   *ZIRCONIUM COMPOUNDS , *CERAMIC MATERIALS , EXPERIMENTAL DATA , THERMODYNAMICS , ZIRCONIUM , BORON , VAPORIZATION , HEAT OF FORMATION , SCIENTIFIC RESEARCH , BORIDES , SPECTRUM ANALYZERS , VAPOR PRESSURE , HIGH TEMPERATURE , MASS SPECTROSCOPY , CARBON


Subject Categories : Inorganic Chemistry


Distribution Statement : APPROVED FOR PUBLIC RELEASE