Accession Number:

AD0450678

Title:

MASS SPECTROMETRIC STUDY OF ZIRCONIUM DIBORIDE

Descriptive Note:

Corporate Author:

UNION CARBIDE RESEARCH INST TARRYTOWN NY

Personal Author(s):

• Trulson, O. C.
• Goldstein, H. W.

Report Date:

1964-10-01

Pagination or Media Count:

20.0

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 kcalmole. 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 kcalmole 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 kcalmole.

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