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dc.contributor.authorAziz, Michael
dc.contributor.authorNygren, Eric
dc.contributor.authorHays, James F.
dc.contributor.authorTurnbull, David
dc.date.accessioned2010-02-17T19:11:54Z
dc.date.issued1985
dc.identifier.citationAziz, Michael J., Eric Nygren, James F. Hays, and David Turnbull. 1985. Crystal growth kinetics of boron oxide under pressure. Journal of Applied Physics 57 (6): 2233-2242.en_US
dc.identifier.issn0021-8979en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:3645198
dc.description.abstractWe have measured the crystal growth rate u of B2O3-I in the amorphous phase, as it varied over five orders of magnitude with changes in temperature and pressure. We eliminated the crystal nucleation barrier by seeding the surface of boron oxide glass with crystals. u became measurable only when the pressure exceeded a threshold level near 10 kbar. Using the published thermodynamic information on the B2O3 system and a crude free-energy model for the crystal and glass phases, we account qualitatively for our results with the theory of crystal growth limited by the rate of two-dimensional nucleation of monolayers. The constants for the prefactor, activation energy, activation volume, and ledge tension are determined by fitting. By adjusting the thermodynamic parameters to a set of values that are well within the ranges delineated by their experimental uncertainties, we account quantitatively for the measured growth rates from 300 to 500 °C and from 0 to 30 kbar with the following relation: u(T,P)=(785 m/s)[||DeltaGm||/(RT)]1/6 ×exp[pi×3 Å(420 erg/cm2)2(28 cm3/mole)/(3 kTDeltaGm)]exp[−10 366 cal/mole/(RT)] ×exp[−P×16 cm3/mole/(RT)]×{1−exp[DeltaGm/(RT)]}2/3, with the driving free energy given by DeltaGm(T,P)=(13 cm3/mole) [PM(T)−P] and the melting curve given by PM(T)=(T−450 °C)/(42.6 K/kbar). The "B2O3 crystallization anomaly", that crystals have never been observed to grow at atmospheric pressure, is explained, since according to our model, the frequency of two-dimensional nucleation is negligible at all temperatures at pressures less than 10 kbaren_US
dc.description.sponsorshipEngineering and Applied Sciencesen_US
dc.language.isoen_USen_US
dc.publisherAmerican Institute of Physicsen_US
dc.relation.isversionofhttp://scitation.aip.org/vsearch/servlet/VerityServlet?KEY=JAPIAU&possible1=boron%20oxide&smode=results&possible1zone=article&maxdisp=10en_US
dash.licenseLAA
dc.subjectglassen_US
dc.subjecthigh temperatureen_US
dc.subjectmeltingen_US
dc.subjectvery high pressureen_US
dc.subjectkineticsen_US
dc.subjectcrystal growth from meltsen_US
dc.subjectcrystallizationen_US
dc.subjectfree energyen_US
dc.subjectthermodynamic propertiesen_US
dc.subjectmonolayersen_US
dc.subjectphase transformationsen_US
dc.subjectcrystal-en_US
dc.subjectnucleationen_US
dc.subjectactivation energyen_US
dc.subjectpressure effectsen_US
dc.subjecttemperature effectsen_US
dc.subjectboron oxidesen_US
dc.subjectamorphous stateen_US
dc.titleCrystal Growth Kinetics of Boron Oxide Under Pressureen_US
dc.typeJournal Articleen_US
dc.description.versionVersion of Recorden_US
dc.relation.journalJournal of Applied Physicsen_US
dash.depositing.authorAziz, Michael
dc.date.available2010-02-17T19:11:54Z
dash.contributor.affiliatedAziz, Michael


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