MASS SPECTROMETRIC STUDY OF ZIRCONIUM DIBORIDE
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1964
- Accession Number
- AD0450678
Entities
People
- H. W. Goldstein
- O. C. Trulson