Thermoelastic equation of state of boron suboxide B₆O up to 6 GPa and 2700 K: simplified anderson-grüneisen model and thermodynamic consistency

• Дата: 2014
• Автори: Kurakevych, O.O., Solozhenko, V.L.
• Формат: Стаття
• Мова: English
• Опубліковано: Інститут надтвердих матеріалів ім. В.М. Бакуля НАН України 2014
• Назва видання: Сверхтвердые материалы
• Теми: Получение, структура, свойства
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/126121
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Thermoelastic equation of state of boron suboxide B₆O up to 6 GPa and 2700 K: simplified anderson-grüneisen model and thermodynamic consistency / O.O. Kurakevych, V.L. Solozhenko // Сверхтвердые материалы. — 2014. — № 4. — С. 68-77. — Бібліогр.: 43 назв. — англ.

The p-V-T equation of state of superhard boron suboxide B₆O has been measured up to 6 GPa and 2700 K using multianvil technique and synchrotron X-ray diffraction. To fit the experimental data, the theoretical p-V-T equation of state has been derived in approximation of the constant value of the Anderson-Grüneisen parameter δT. Bulk modulus B₀ =181 GPa and its first pressure derivative B₀' = 6 at 300 K; two parameters describing thermal expansion at 0.1 MPa, i.e., a = 1.4×10–5 K–1 and b = 5×10–9 K–2 as well as dT = 6 have been included in the model. The good agreement between fitted and experimental isobars has been achieved to the absolute volume changes up to 5 % as compared to the volume at standard conditions, V0. The fitted thermal expansion at 0.1 MPa well consistent with the experimental data as well as with ambient-pressure heat capacity cp, bulk modulus B₀ and dT describing its evolution with volume and temperature have been discussed. The fitted value of Grüneisen parameter g = 0.85 in agreement with previous empiric estimations for B₆O and experimental values for other boron-rich solids has been reported.