Isotopic effect of boron carbide thermal conductivity

Karumidze, G. S.; Shengelia, L.A.

doi:10.1016/0925-9635(94)90023-x

Cited by 7 publications

(2 citation statements)

References 3 publications

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“…This is attributed to the increase in the bonding energy per unit mass and the phonon velocity as a lighter isotope is substituted for a heavier isotope. 58 Electrical conductivity in boron carbide was studied by Wood et al 49 and Matusi et al 55 Charge carriers in boron carbide are holes which form small polarons and move by phonon assisted hoping between carbon atoms located at geometrically non-equivalent sites. 49 The nonequivalence arises from two sources.…”

Section: Structure Sensitive Propertiesmentioning

confidence: 99%

Synthesis and consolidation of boron carbide: a review

Suri

Subramanian

Sonber

et al. 2010

International Materials Reviews

623

290

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Boron carbide is a strategic material, finding applications in nuclear industry, armour for personnel and vehicle safety, rocket propellant, etc. Its high hardness makes it suitable for grinding and cutting tools, ceramic bearing, wire drawing dies, etc. Boron carbide is commercially produced either by carbothermic reduction of boric acid in electric furnaces or by magnesiothermy in presence of carbon. Since many specialty applications of boron carbide require dense bodies, its densification is of great importance. Hot pressing and hot isostatic pressing are the main processes employed for densification. In the recent past, various researchers have made attempts to improve the existing methods and also invent new processes for synthesis and consolidation of boron carbide. All the techniques on synthesis and consolidation of boron carbide are discussed in detail and critically reviewed.

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Section: Structure Sensitive Propertiesmentioning

confidence: 99%

Synthesis and consolidation of boron carbide: a review

Suri

Subramanian

Sonber

et al. 2010

International Materials Reviews

623

290

View full text Add to dashboard Cite

show abstract

“…Measurements for LiF, 36 Ge, 21,37,38 and diamond 22,23,39,40 were performed in the temperature range between 4 K and room temperature or higher. Studies of solid 4 He, 41,42 LiF, 36,43,44 Ne, 45,46 and B 4 C, 47 cover only a rather limited temperature range. Effects similar to those caused by isotopic disorder are produced by very heavy isolated impurities in quantum crystals, e.g., Ar, Ne in parahydrogen.…”

Section: ͑1͒mentioning

confidence: 99%

Thermal conductivity of germanium crystals with different isotopic compositions

et al. 1997

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We have measured the thermal conductivity of seven germanium crystals with different isotopic compositions in the temperature range between 2 K and 300 K. These samples, including one made of highly enriched 70 Ge͑99.99%͒, show intrinsic behavior at room temperature with the exception of a p-type sample with ͉N d-N a ͉Х2ϫ10 16 cm Ϫ3. The ''undoped'' samples exhibit a T 3 dependence at low temperatures, basically determined by boundary scattering. The maximum value of ͑which falls in the range between 13 K and 23 K͒ is found to be a monotonically decreasing function of the isotopic mass variance parameter g. The maximum m measured for the most highly enriched 70 Ge͑99.99%͒ sample is 10.5 kW/mK, one order of magnitude higher than for natural germanium. The experimental data have been fitted with the full Callaway theory, modified by treating transverse and longitudinal modes separately, using three free adjustable parameters for each set of modes to represent anharmonic effects plus the calculated contributions from isotopic and boundary scattering. For the isotopically purest 70 Ge͑99.99%͒ sample, dislocation scattering, or a similar mechanism, must be added in order to fit the data. We have also checked the effect of various surface treatments on the thermal conductivity in the low temperature region. The highest values of are found after polish etching with a SYTON suspension. ͓S0163-1829͑97͒00539-0͔

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Boron compounds with group IV elements: boron carbide: further properties

Landolt-Börnstein - Group III Condensed Matter

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Isotopic effect of boron carbide thermal conductivity

Cited by 7 publications

References 3 publications

Synthesis and consolidation of boron carbide: a review

Synthesis and consolidation of boron carbide: a review

Thermal conductivity of germanium crystals with different isotopic compositions

Boron compounds with group IV elements: boron carbide: further properties

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