Relaxation modes of trapped crystal point defects: The three-neighbor shells model in NaCl

Franklin, A.D.; Shorb, A.; Wachtman, J. B.

doi:10.6028/jres.068a.041

Cited by 26 publications

(5 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Three general types of interferometers that produce fringes of equal thickness are also described in an ASTM method of test [235] Except for a small correction due to refraction of the x-rays [223] Furnaces that have precision sample movements [245,246] [83] has found this to be the case for borosilicate glasses, as indicated in figure 21, and Brueckner [248] complete success. An equation derived by Turner [249] seems to be very useful in spite of its simplicity.…”

Section: Interferometersmentioning

confidence: 99%

“…V. J., Influence of Ti02 on properties of glasses in the system K20-PbO-Si02-Ti02 and its relation to structure, 46, 107 (1963 48, 157 (1965 37, 193 (1958). [235] Res. NBS 23, 179 (1939).…”

Section: Interferometersmentioning

confidence: 99%

“…In figure 22, the thermal resistivity data of Taylor [236] Lorenz function (after Williams [235]). High temperature thermal resistivity of two samples of high density beryllium oxide (after Taylor [236]).…”

Section: Interferometersmentioning

confidence: 99%

See 2 more Smart Citations

Mechanical and thermal properties of ceramics :

Wachtman¹

1969

115

139

View full text Add to dashboard Cite

Ceramics are frequently manufactured by a heating process which appears deceptively simple but which usually involves a number of competing reactions and transport processes occurring at different rates. Optimizing a particular property requires a starting composition and heat treatment which produces the final composition and microstructure (usually denoted by the word "character") needed for that property. In principle one should begin with the properties needed, determine the character required from an understanding of the propertycharacter relationship, and design the processing from an understanding of the chemistry and mass transport which are involved. In practice the understanding of both areas is limited so that empirical procedures, guided by some degree of fundamental understanding, are generally used.The current status of ceramic processing was surveyed by the Materials Advisory Board ad hoc Committee on Ceramics Processing, chaired by Professor J. A. Pask, and their conclusions are available in Ceramic Processing, National Academy of Sciences Publication 1576 (1968). The importance of an improved understanding and use of the property-character relationship by users of ceramics as well as producers is emphasized. In particular, the user should understand that many properties depend on other aspects of character in addition to gross chemical composition. The engineer who specifies that a part be made of "alumina" is leaving the strength very poorly specified; commercial alumina ceramics range in strength from values below 2000 psi for certain refractories to values approaching 100,000 psi for certain tool bits and other special purpose ceramics. The present symposium is aimed primarily at the users of ceramics but it is hoped that producers will also find a systematic review of property-character relationships useful.Properties of ceramics in general form too broad and diverse a subject to be effectively treated in this symposium; the properties selected for treatment are those related to mechanical and thermal behavior. Ceramics are frequently used to exploit their thermal properties and also as structural members in which case their deformation and ultimate fracture under load are of obvious importance. In many applications ceramics are used to exploit other properties, but mechanical and thermal properties are usually still important in determining the size, weight, and cost of the parts involved. Ceramics are, of course, particularly well suited to high temperature applications but the conditions of high temperature use frequently create thermal gradients with accompanying thermal stress. The symposium accordingly includes IV thermal factors not only because of their direct engineering importance, but also because of their role in limiting load-bearing capacity at high temperatures; i.e., the melting points, thermal expansion, thermal conductivity, and thermal radiation properties are surveyed.The practical utilization of high-performance ceramics requires more than their successful production ...

show abstract

Section: Interferometersmentioning

confidence: 99%

“…V. J., Influence of Ti02 on properties of glasses in the system K20-PbO-Si02-Ti02 and its relation to structure, 46, 107 (1963 48, 157 (1965 37, 193 (1958). [235] Res. NBS 23, 179 (1939).…”

Section: Interferometersmentioning

confidence: 99%

See 1 more Smart Citation

Mechanical and thermal properties of ceramics :

Wachtman¹

1969

115

139

View full text Add to dashboard Cite

show abstract

“…wx is the frequency with which a vacancy jumps from one nearest neighbour site to another, w2 is the solute-vacancy exchange frequency and w3 is the frequency with which a vacancy jumps from one nearest neighbour site to a (particular) more distant position. Corresponding to the fact th a t Q has only one element there is only one mode of relaxation (but note th a t a more elaborate analysis was made by Franklin (1964)); the corresponding tim e constant is…”

Section: <F>(t) = O-0s(t)/n + /1(n'ni)and(t)(nlii')mentioning

confidence: 99%

Atomic transport via point defects in crystals. II. Atomic mobilities and dielectric relaxation

1984

Proc. R. Soc. Lond. A

View full text Add to dashboard Cite

The general formulation of the kinetic theory of isothermal solid state diffusion applicable to systems showing small degrees of vacancy and interstitial disorder that was presented in a previous paper (Franklin & Lidiard, Proc. R. Soc. Lond . A 389, 405-431 (1983)) is here extended to describe atomic transport in such isothermal systems under the influence of external scalar potential fields (for example, electric, gravitational, centrifugal fields). For steady fields the results verify the correctness of the phenomenological equations suggested for solid state transport processes by the theory of non-equilibrium thermodynamics and provide expressions for the phenomenological transport coefficients L ij in terms of microscopic quantities characterizing the defect species and their movements. In particular, it is shown that the same expressions for these transport coefficients are obtained from the atomic fluxes coming from ‘drift’ under applied fields, as from diffusion arising from imposed concentration gradients. The dielectric response function for use with time-dependent fields is also obtained. It is made up of two parts; one corresponding to the d. c. conductivity, the other to a set of Debye relaxation modes. It is demonstrated that the occurrence of association and dissociation reactions among the defects influences both the relaxation times and the strengths of these modes. A brief examination of the example of solute-vacancy pairs in a f. c. c. lattice shows that these influences can be substantial and qualitatively significant.

show abstract

“…L'expression finale de P n'est donc fonction que des diffbrences entre les energies d'association des divers types de complexes et prend la formei = l P = (8e2a2Exi [l + exp (E,-E,)/kT+ exp (E5-E3)/kT + 3 exp ( E l -E , ) / k T ] } x x ( 3 k T [4 +exp (E4-E3)/kT + 2 exp (E,-E3)/kT+4exp ( E l --E,)/kT+(5) + 4 exp (E5 -E 3 ) / k T ] } -l Variations de type IV aussi lies que ceux de type I11 ( H) ; pour des complexes de type IV moins li6s que ceux de type 111 (A). Les courbes tillon tenant compte des cinq premiers comhiergies d'association Coulombiennes ( 0 ) ; pour en pointill& ne tiennent respectivement compte que des deux premiers types de complexes I11 e t IV: (o), (0) et ( A ) El, E,, E3, E4 et E , sont les valeurs absolues des energies d'association des complexes de types I, 11, 111, IV et V reportees sur le diagramme de laFig.…”

unclassified

Modes de relaxation électriques dans les cristaux ioniques de type NaCl dopés par des impuretés trivalentes

Brun

Dansas

1974

phys. stat. sol. (b)

View full text Add to dashboard Cite

A. BRUN et P. DANSAS : Modes de relaxation klectriques dans les cristaux ioniques 201 phys. stat. sol. (b) 66, 201 (1974) Subject classification: 10.2 and 14.4; 22.5.2 Laboratoire de Physique Electronique, Universitk Paris Sud, Orsay ( a ) , et Laboratoire de Physique de la ilfatikre Condenske, h'ice (b) Modes de relaxation Blectriques dans les cristaux ioniques de type NaCl dopes par des impuretes trivalentes Par A. BRUN (a) et P. DANSAS~) (b) On a utilis6 u n modhle A puits de potentiel pour dkterminer les modes de relaxation 6lectriquement actifs et les temps de relaxation correspondants pour un cristal de type NaCl dope par une impuretk trivalente en substitution. On a calculi! Bgalement les polarisations correspondantes A chaque mode de relaxation et discut6 de l'intbrbt particulier des mesures "di6lectriques" dans ce cas.In order t o obtain the electrically active relaxation modes and relaxation times for the NaCl structure with a trivalent substitutional impurity, a potential-well model is used. Each corresponding polarization is calculated and the full interest of dielectric measurements in this case is examined.

show abstract

Relaxation modes of trapped crystal point defects: The three-neighbor shells model in NaCl

Cited by 26 publications

References 7 publications

Mechanical and thermal properties of ceramics :

Mechanical and thermal properties of ceramics :

Atomic transport via point defects in crystals. II. Atomic mobilities and dielectric relaxation

Modes de relaxation électriques dans les cristaux ioniques de type NaCl dopés par des impuretés trivalentes

Contact Info

Product

Resources

About