Reversible Nanodiamond-Carbon Onion Phase Transformations

Abstract

Because of their considerable science and technical interest, nanodiamonds (3-5 nm) are often used as a model to study the phase transformation between graphite and diamond. Here we demonstrated that a reversible nanodiamond-carbon onion phase transformation can become true when laser irradiates colloidal suspensions of nanodiamonds at the ambient temperature and pressure. Nanodiamonds are first transformed to carbon onions driven by the laser-induced high temperature in which an intermediary bucky diamond phase is observed. Sequentially, carbon onions are transformed back to nanodiamonds driven by the laser-induced high temperature and high pressure from carbon onions as nanoscaled temperature and pressure cell upon the laser irradiation process in liquid. Similarly, the same bucky diamond phase serving as an intermediate phase is found during the carbon onion-to-nanodiamond transition. To have a clear insight into the unique phase transformation the thermodynamic approaches on the nanoscale were proposed to elucidate the reversible phase transformation of nanodiamond-to-carbon onion-to-nanodiamond via an intermediary bucky diamond phase upon the laser irradiation in liquid. This reversible transition reveals a series of phase transformations between diamond and carbon allotropes, such as carbon onion and bucky diamond, having a general insight into the basic physics involved in these phase transformations. These results give a clue to the root of meteoritic nanodiamonds that are commonly found in primitive meteorites but their origin is puzzling and offers one suitable approach for breaking controllable pathways between diamond and carbon allotropes.

Reinforcement of nylon 6,6/nylon 6,6 grafted nanodiamond composites by in situ reactive extrusion

“…The thermal degradation of the nanodiamonds at 540 °C implied that a graphene-like amorphous layer existed on the nanodiamond surface. The oxidation of the nanodiamonds occurred at 540 °C with the removal of the amorphous graphene-like layer28. In contrast, the thermogram of the PA66 presented thermal degradation starting at about 360 °C.…”

Nano-Diamond Hybrid Materials for Structural Biomedical Application

“…On this morphological transition at the interface, it has been recently demonstrated by Xiao et al (2014) that reversible nanodiamond-graphitic carbon onion like phase transformation can occur even at room temperature and pressure leading to the formation of diamond cores with graphitic shells (bucky-diamond) (Fig. 1C) (Barnard and Sternberg, 2007).…”

Hybrid Ceramo-Polymeric Nano-Diamond Composites

“…A reversible reverse phase transformation in a nanodiamond-graphite cluster was observed by Xiao et al (2014) appear in this morphological transition interface that leads to the diamond formation of bucky, characterized by a diamond core, a graphic shell (schematized in Fig. 4) (Barnard and Sternberg, 2007).…”