Self-diffusion of potassium in potassium azide

Sharma, J. K. N.; Laskar, A.L.

doi:10.1016/s0022-3697(73)80006-x

Cited by 6 publications

(6 citation statements)

References 7 publications

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“…Analysis of the experimental data of Sharma and Laskar [5] for the temperature dependence of tracer diffusion parallel to the c-axis, using theoretical values [9] for the anisotropy of vacancy migration energies, leads to values of the cation vacancy migration energy of 0.55 and 0.8 eV parallel and perpendicular to the c-axis respectively. However, analysis of the single datum for the anisotropy of the diffusion coefficient leads to migration energies for perpendicular and parallel vacancy motion of 0.82 and 0.78 eV respectively, i.e.…”

Section: Discussionmentioning

confidence: 99%

“…Thus determining (1 -T);l, (1 -!P);l, and (1 -T);I yields 5 and co from equations (10) and (11) and the correlation factors f Z Z and f Z Z from equation (5).…”

Section: Evaluation Of the Correlation Factormentioning

confidence: 99%

“…where the usual Arrhenius temperature dependence for the vacancy jump frequencies has been assumed and Em is the migration energy for the vacancy. I n the temperature range and for the crystal purity employed by Sharma and Laskar [5] in their diffusion measurements, the vacancy concentration is controlled by the crystal purity and may thus be considered essentially temperature independent (extrinsic conditions). For this case, the activation energy for diffusion is determined by the vacancy migration energy and the temperature dependence of the correlation factor.…”

Section: Evaluation Of the Correlation Factormentioning

confidence: 99%

“…The experimental results of Sharma and Laskar [5], for diffusion parallel to the c-axis between 358 and 527 K, which yield Q,, = 0.8 eV are not consistent with the predictions of any of the three potentials which imply Q,, = 0.2, 0.5 5 Q,, 5 0.7; and 0.9 5 Q,, 5 1.4 eV for the GWI, GWII, and DS potentials respectively. A potential somewhere "between" GWII and DS appears to be necessary.…”

Section: Evaluation Of the Correlation Factormentioning

confidence: 99%

“…No clear evidence for azide ion transport exists although ionic conductivity measurements close to the thermal decomposition temperature [4] may show a contribution from the azide sublattice. Tracer diffusion measurements [5] have also been made for the potassium sublattice in a direction parallel to the c-axis. These measurements show a temperature dependence of the diffusion coefficient that is consistent with the extrinsic ionic conductivity data 154 A. G .…”

Section: Introductionmentioning

confidence: 99%

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A Theoretical Analysis of Cation Diffusion in Potassium Azide

Danemar

Royce

Welch

1974

Physica Status Solidi (b)

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A theoretical analysis has been made of the temperature dependence and anisotropy of the self-diffusion of tracer potassium ions in KN,. A vacancy mechanism is assumed, and the effects of correlation on diffusion are examined. An approximate analytic expression is obtained for the correlation factor, and its validity is determined by comparison with more accurate numerical calculations. The temperature dependence of the elements of the diffusion tensor including correlation is evaluated, making use of theoretical values of the migration energy of cation vacancies, and the role of correlation in determining the crystallographic anisotropy of cation diffusion is discussed. Comparison is made to available experimental data.Es wird die theoretische Analyse der TemperaturabhLngigkeit und Anisotropie der Selbstdiffusion von radioaktiv markierten Kaliumionen in KN, durchgefuhrt. Es wird ein Leerstellenmechanismus angenommen und die Einflusse der Korrelation auf die Diffusion untersucht. Ein geeigneter analytischer Ausdruck fur den Korrelationsfaktor wird erhalten und seine Gultigkeit durch Vergleich mit genaueren numerischen Rechnungen bestimmt. Die Temperaturabhangigkeit der Elemente des Diffusionstensors wird unter EinschluD der Korrelation berechnet, wobei theoretische Werte der Wanderungsenergie der Kationenleerstellen benutzt werden und die Rolle der Korrelation bei der Bestimmung der Kristallanisotropie der Kationendiffusion diskutiert wird. Die Ergebnisse werden mit erhaltlichen experiment ellen Werten verglichen.

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Section: Discussionmentioning

confidence: 99%

“…Thus determining (1 -T);l, (1 -!P);l, and (1 -T);I yields 5 and co from equations (10) and (11) and the correlation factors f Z Z and f Z Z from equation (5).…”

Section: Evaluation Of the Correlation Factormentioning

confidence: 99%

Section: Evaluation Of the Correlation Factormentioning

confidence: 99%

Section: Evaluation Of the Correlation Factormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Theoretical Analysis of Cation Diffusion in Potassium Azide

Danemar

Royce

Welch

1974

Physica Status Solidi (b)

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Activation Energies for Migration of K⁺ and N⁰ in KN₃

Chang

Neuberger

Fischer

1979

Physica Status Solidi (b)

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Activation energies for the migration of K+ and KO interstitials in KN, crystals are calculated.The total cohesive energy is obtained from a modified Born model. Both double-spherical and triple-spherical potentials are used as the repulsive interaction. Polarization effects according to the Hatcher-Dienes scheme are employed. No interstitial migration is found to require very little energy and thus becomes a good candidate for explaining the explosive instability of the azides. Les energies d'activation pour la migration des ions interstitids K+ e t N O dans le KN, ont Bt6calcukes. L'Bnergie totale de cohhsion a kt6 obtenue a l'aide d'un modde de Born modifii.. Des potentiels doublement-sph6riques, ainsi que triplement-sphhriques ont 6tA utilises dans le calcul de 1'Bnergie d'interaction rhpulsive. Les effets de polarisation ont BtB determines & l'aide d'un modkle de Hatcher e t Dienes. On a trouve que la migration de l'interstitiel N O ne demande que peu d'knergie, de sorte que ceci pourrait expliquer l'instabilitk explosive des nitrures.

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