VAPOR PRESSURES OF INORGANIC SUBSTANCES: ZIRCONIUM DIOXIDE

Abstract

The Knudsen effusion method was used to measure the vapor pressure of ZrO2 and a stoichiometric ZrO2+Zr mixture between 2014 and 2290 K. The pressure was calculated from rate of effusion data, using the equation p=m square root of 2 pi RT/M (p is the pressure in atmospheres; m, the rate of effusion in g/sq cm/sec; R, the molar gas constant; and M, the mol wt of the vapor). The same rates of evaporation in both cases indicated that ZrO2 vaporizes as ZrO2. The mean heat of evaporation (140.3 + or - 1.5 kcal) of ZrO2 was determined from the slope of the log p vs 1/T plot for the stated temperature range. By using a previously determined heat of evaporation for Zr and delta H sub f of ZrO2(s) (NBS values), 375 + or - 5 kcal/mol was obtained for the heat of dissociation for ZrO2 (g) into Zr (g) and O (g). The bp pf ZrO2 was calculated to be 3735 K from the NBS data for temperature, heat, and entropy of fusion. (See also AD18365)

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Document Details

Document Type
Technical Report
Publication Date
Aug 15, 1953
Accession Number
AD0018364

Entities

People

  • Herrick L. Johnston
  • Masaru Nakata
  • Michel Hoch

Organizations

  • Ohio State University

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Boiling Point
  • Ceramic Materials
  • Chemistry
  • Dissociation
  • Effusion
  • Equations
  • Evaporation
  • Heat Energy
  • Heat Of Vaporization
  • Jet Propulsion
  • Metals
  • Military Research
  • Navy
  • New York
  • Standards
  • Thermodynamics
  • Vapor Pressure

Readers

  • Combustion science or combustion engineering.
  • Fire Suppression Systems Design.
  • Powder metallurgy of Titanium alloys.