Thermodynamic Study of Al2O3 Using a Mass Spectrometer

Drowart, Jean; DeMaria, G.; Burns, Robert C.; Inghram, Mark G.

doi:10.1063/1.1730923

Cited by 188 publications

(41 citation statements)

References 21 publications

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“…However, x-ray patterns of the specimens optically examined showed only reflections representing a-AI20:l. The unit cell dimensions , determ ined from back reflection measurements, were the same as those of the unheated starting materials. Apparently the dissociation process follows the equation generally postulated in vapor pressure studies [25]:…”

Section: Phase Equilibriamentioning

confidence: 90%

Effect of environment upon the melting point of Al2O3

Schneider

McDaniel

1967

J. RES. NATL. BUR. STAN. SECT. A.

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The me ltin g point of AI, O" has bee n d e termined in vac uum . a ir. a rgon. a nd he lium utilizin)': iridium or tun ),:s te n co ntain ers. A ll me ltin g po int expe rim e nt s we re conduc ted in indu c ti on furna ces capab le of hea ti ng s ma ll sa mpl es und er b lackbody co ndition s to 3000 °C in vacuum. 2600 °C in inert at mosp he res. a nd 2400 °C in air. Temperatures we re co ntinu ous ly mo nit o red wit h a reco rding phutoe lec tri c pyrome ter whi c h has a se n sitivity of±0.2° at 1063 °C and ± 10 at 2000 0c. Meltin g points were determ in ed on s pec im ens having a purity in excess of 99.9 pe rce nt. T he data indi c at e d that th e me ltin g poin t of AI ,O" d e te rmin ed in vac uum (-6.5 X 10 -5 torr) is 2051 °C OPTS). T he overa ll maximum un ce rt a int y was es tim ate d to be ± 6 0c. Th e mea s ure me nt s th e m se lves we re prec ise within ± 1.5 0c. Vacuum trea tm e nt had leas t de t rimenta l e ffec t upon th e AI,03 spec im e ns. Eac h of the gaseous a tmo s ph e res in c lu ding air yie lded lower me lti ng point s for AI,O", p res umably d ue to a premeltin g p he nom e no n.Key Word s : A I,O". di ss ocia tion. e nvironm e nt a l e ffec ts . me ltin g po int. prc mc ltin g:.

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Section: Phase Equilibriamentioning

confidence: 90%

Effect of environment upon the melting point of Al2O3

Schneider

McDaniel

1967

J. RES. NATL. BUR. STAN. SECT. A.

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“…Figure 2 shows comparisons of the observed and calculated partial vapor pressures of oxide gases over pure molten oxides. Figure 2a shows Knudsen effusion mass spectrometry measurements of the AlO partial vapor pressure over molten alumina (Drowart et al, 1960;Farber et al, 1972;Fig. 2.…”

Section: Comparisons With Prior Workmentioning

confidence: 99%

A thermodynamic model of high temperature lava vaporization on Io

Schaefer

Fegley

2004

Icarus

137

121

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“…Al 2 O 2 has been detected mass spectrometrically in the vapor over alumina [41,42]. It is a product of the reactions of pulsed-laser evaporated aluminum atoms with molecular oxygen [36].…”

Section: Aluminum Oxidesmentioning

confidence: 99%

Thermochemistry of aluminum species for combustion modeling from Ab Initio molecular orbital calculations

Swihart

Catoire

2000

Combustion and Flame

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High accuracy ab initio methods for computational thermochemistry have been applied to aluminum compounds expected to be present during combustion of aluminum particles. The computed enthalpies of formation at 298.15 K agree well with experimental values from the literature for AlCl, AlCl 3 , AlO, AlOAl, linear OAlO, planar Al 2 O 2 , AlOH, AlH, and AlN. The agreement is fair for AlCl 2 . Major revisions to the recommended thermochemistry must be considered for OAlCl, OAlH, OAlOH, and AlC. This is not surprising since the thermodynamic data for OAlCl, OAlH, OAlOH, and AlC are given in the literature as rough estimates. Calculated thermochemical data are also presented for several species never studied experimentally, including AlH 2 , AlH 3 , AlOO, cyclic-AlO 2 , linear AlOAlO, AlHCl, AlHCl 2 , and others. Based on the performance of the CBS-Q and G2 methods observed in other systems, the calculated enthalpies of formation would be expected to be accurate to within Ϯ1 to 2 kcal mol Ϫ1 . However, relatively large differences between the results from the CBS-Q and G2 methods for the aluminum oxides indicate that the uncertainties are slightly larger for these compounds. The thermochemistry proposed here is shown to predict substantially different equilibrium composition from the thermochemistry previously available in the literature.

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Thermodynamic Study of Al2O3 Using a Mass Spectrometer

Cited by 188 publications

References 21 publications

Effect of environment upon the melting point of Al2O3

Effect of environment upon the melting point of Al2O3

A thermodynamic model of high temperature lava vaporization on Io

Thermochemistry of aluminum species for combustion modeling from Ab Initio molecular orbital calculations

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