Hard and superhard carbon phases synthesised from fullerites under pressure

• Дата: 2012
• Автори: Brazhkin, V.V., Lyapin, A.G.
• Формат: Стаття
• Мова: English
• Опубліковано: Інститут надтвердих матеріалів ім. В.М. Бакуля НАН України 2012
• Назва видання: Сверхтвердые материалы
• Теми: Получение, структура, свойства
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/126011
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Hard and superhard carbon phases synthesised from fullerites under pressure / V.V. Brazhkin, A.G. Lyapin // Сверхтвердые материалы. — 2012. — № 6. — С. 75-105. — Бібліогр.: 122 назв. — англ.

A review has been presented on the structural and mechanical properties of hard carbon phases synthesized from fullerite C₆₀ under pressure. The density and nanostructure have been recognized as the key parameters defining the mechanical properties of hard carbon phases. By suggesting a version of the transitional high-pressure diagram of C₆₀ (developed up to 20 GPa), the three areas of the formation of hard carbon phases have been highlighted. The corresponding phases of superhard carbon are (1) disordered sp²-type atomic structures at moderate pressures and high temperatures (> 1100 K), (2) three-dimensionally polymerized C₆₀ structures at moderate temperatures and high pressures (> 8 GPa), and (3) sp³-based amorphous and nanocomposite phases at high pressures and temperatures. First region can be in turn separated into 2 subparts with different peculiarities of sp² structures and properties: low pressure part (0.1–2 GPa) and high-pressure part (2–8 GPa). Temperature can be recognized as a factor responsible for the formation of nanostructures by the partial destruction of molecular phases, whereas pressure is a factor responsible for stimulating the formation of rigid polymerized structures consisting of covalently bonded C₆₀ molecules, whereas the combination of both factors leads to the formation of atomic-based phases with dominating sp³ bonding.