Shock-induced transformation of β-Si3N4 to a high-pressure cubic-spinel phase

Sekine, Toshimori; He, Hongliang; Kobayashi, Takayuki; Zhang, Ming; Xu, Fangfang

doi:10.1063/1.126756

Cited by 143 publications

(92 citation statements)

References 13 publications

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“…Experiments showed that the cubic spinel γ-Si 3 N 4 can be obtained from both hexagonal α-and β-Si 3 N 4 upon com-pression and simultaneous in situ heating. [3][4][5][6][7] The γ phase is quenchable to the ambient condition, and it remains stable at temperatures ranging up to about 1670 K at ambient pressure. 23,24 When γ-Si 3 N 4 "decomposes" at ambient pressure upon heating, the samples may consist of both α-and β-Si 3 N 4 .…”

mentioning

confidence: 99%

Equilibrium and metastable phase transitions in silicon nitride at high pressure: A first-principles and experimental study

Dong

McMillan

et al. 2011

Phys. Rev. B

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We have combined first-principles calculations and high pressure experiments to study pressure induced phase transitions in silicon nitride (Si3N4). Within the quasi-harmonic approximation, we predict that the α phase is always metastable relative to the β phase over the wide pressuretemperature range. Our lattice vibration calculations indicate that there are two significant and competing phonon-softening mechanisms in the β-Si3N4, while phonon softening in the α-Si3N4 is rather moderate.When the previously observed equilibrium high-pressure and high-temperature β→γ transition is by-passed at room temperatures (RT) due to kinetic reasons, the β phase is predicted to undergo a first-order structural transformation to a denser P6 phase above 39 GPa. The estimated enthalpy barrier height is less than 70 meV/atom, which suggests that the transition is kinetically possible around room temperatures. This predicted new high-pressure metastable phase should be classified as a "post-phenacite" phase. Our high-pressure X-ray diffraction experiment confirm this predicted room-temperature phase transition around 34 GPa. No similar RT phase transition is predicted for α-Si3N4. Furthermore, we discuss the differences in pressure dependencies of phonon modes in the α, β and γ phases and the consequences on their thermal properties. We attribute the phonon modes with negative Grüneisen ratios in the α and β phases as the cause of the predicted negative thermal expansion coefficients (TEC) at low temperatures in these two phases, and predict no negative TEC in the γ phase.

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mentioning

confidence: 99%

Equilibrium and metastable phase transitions in silicon nitride at high pressure: A first-principles and experimental study

Dong

McMillan

et al. 2011

Phys. Rev. B

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“…Consequently, the study of the transition from low pressure phases (α, β) to a high density c-phase and the construction of silicon nitride phase diagram are of importance as it will allow optimizing the conditions of the cphase synthesis in shock and detonation waves. It was found in [2] that the increase in temperature in recovery shock experiments brings down the transformation pressure threshold to the c-phase. To further investigate this phenomenon we constructed a Hugoniot and a sound velocity pressure dependence curve for porous silicon nitride samples, which allowed us to reach higher temperatures under shock loading.…”

Section: Introductionmentioning

confidence: 99%

“…In 1999 the A. Zerr group [1] synthesized a new high density c-Si 3 N 4 modification with a cubic crystalline structure in several tens of nanograms in a laser heating diamond anvil cell at 15 GPa and 2800 K from a low pressure Si 3 N 4 modification. Later the same modification was synthesized by shock wave [2] and detonation [3] methods. The determined bulk modulus of c-Si 3 N 4 was about 300 GPa and the hardness exceeded 35 GPa [4] which is slightly higher than for SiO 2 -stishovite (about 33 GPa) [5] often referred to as the third hardest material after diamond and cubic boron nitride [4,5].…”

Section: Introductionmentioning

confidence: 99%

Porous silicon nitride under shock compression

Yakushev¹,

Уткин²,

Zhukov³

2012

AIP Conference Proceedings

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Abstract. The measurements of the Hugoniot and sound velocity pressure dependence in β-Si 3 N 4 porous samples under shock loading up to 55 GPa are presented. The Hugoniot and experimental particle velocity profiles demonstrate no peculiarities arising from the phase transition into high density c-Si 3 N 4 . Nevertheless, it follows from the comparison of measured Hugoniot with the Hugoniot for monolithic samples that phase transition does take place, starting at a much lower pressure of approximately 25 GPa, where the two Hugoniots intersect. The analysis of the positional relationship of the Hugoniots for monolithic and porous samples allowed us to confirm that the transformation pressure threshold decreases with the temperature increase due to a greater heating of porous material under loading. Measurements of sound velocity in shocked samples showed that sound velocity pressure dependence has a kink near 23 GPa, which is very close to the presumable pressure of the transition to c-Si 3 N 4 in porous samples.

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“…Different preparation methods have also been developed. Recently, Sekine et al 15,17 have prepared ␥-Si 3 N 4 by shock-induced transformation of ␤-Si 3 N 4 powder, which may produce ␥-Si 3 N 4 in large scale.…”

Section: Introductionmentioning

confidence: 99%

Phonon spectrum and thermal properties of cubic Si3N4 from first-principles calculations

Fang¹,

Wijs

Hintzen³

2003

Journal of Applied Physics

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The phonon spectrum of cubic Si 3 N 4 was calculated by first-principles techniques. The results permit an assessment of important mechanical and thermo-dynamical properties such as the bulk modulus, lattice specific heat, vibration energy, thermal expansion coefficient, and thermal Grüneisen parameter for this compound. The calculated phonon spectrum shows a gapless spectrum extending to a cutoff energy of ϳ1030 cm Ϫ1 . The calculated Raman-and infrared-active phonon frequencies are compared with measured data in the literature.

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Shock-induced transformation of β-Si3N4 to a high-pressure cubic-spinel phase

Cited by 143 publications

References 13 publications

Equilibrium and metastable phase transitions in silicon nitride at high pressure: A first-principles and experimental study

Equilibrium and metastable phase transitions in silicon nitride at high pressure: A first-principles and experimental study

Porous silicon nitride under shock compression

Phonon spectrum and thermal properties of cubic Si3N4 from first-principles calculations

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