Elastic and thermodynamical properties of cubic (3C) silicon carbide under high pressure and high temperature

Dinesh Varshney,M Varshney,R Khenata,N Singh,S Shriya

doi:10.1007/s40094-015-0183-7

Abstract

Pressure-dependent first-order phase transition, mechanical, elastic, and thermodynamical properties of cubic zinc blende to rock-salt structures in 3C silicon carbide (SiC) are presented. An effective interatomic interaction potential for SiC is formulated. The potential for SiC incorporates long-range Coulomb, charge transfer interactions, covalency effect, Hafemeister and Flygare type short-range overlap repulsion extended up to the second-neighbour ions, van der Waals interactions and zero point energy effects. The developed potential including many body non-central forces validates the Cauchy discrepancy successfully to explain the high-pressure structural transition, and associated volume collapse. The 3C SiC ceramics lattice infers mechanical stiffening, thermal softening, and ductile (brittle) nature from the pressure (temperature) dependent elastic constants behaviour. To our knowledge, these are the first quantitative theoretical predictions of the pressure and temperature dependence of mechanical and thermodynamical properties explicitly the mechanical stiffening, thermally softening, and brittle/ductile nature of 3C SiC and still awaits experimental confirmations.

Highlights

Silicon carbide, (SiC), a high quality technical grade ceramics, possesses wide energy band gap, low density, high strength, low thermal expansion, high thermal conductivity, high hardness, high melting point, large bulk modulus, low dielectric constant, high elastic modulus, excellent thermal shock resistance, and superior chemical inertness
The interatomic interaction potential with charge transfer interactions caused by ions of Si and C atom and covalent nature of Si–Si, Si–C, and C–C bonds are effective in studying the structural phase transitions and elastic properties of tetrahedrally coordinated ceramics 3C silicon carbide (SiC)
Compressions in SiC at higher pressure indicate the mechanical stiffening of lattice

Summary

Introduction

Silicon carbide, (SiC), a high quality technical grade ceramics, possesses wide energy band gap, low density, high strength, low thermal expansion, high thermal conductivity, high hardness, high melting point, large bulk modulus, low dielectric constant, high elastic modulus, excellent thermal shock resistance, and superior chemical inertness. The IV–IV SiC compound possesses tetrahedral of C and Si atoms with strong bonds in the crystal lattice and the availability of wide variety of its polytypes with unique structural and electronic properties. The high thermal conductivity coupled with low thermal expansion and high strength gives this material exceptional thermal shock resistant qualities.

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Conclusion