Synthesis of quenchable amorphous diamond

Abstract

Diamond owes its unique mechanical, thermal, optical, electrical, chemical, and biocompatible materials properties to its complete sp 3-carbon network bonding. Crystallinity is another major controlling factor for materials properties. Although other Group-14 elements silicon and germanium have complementary crystalline and amorphous forms consisting of purely sp 3 bonds, purely sp 3-bonded tetrahedral amorphous carbon has not yet been obtained. In this letter, we combine high pressure and in situ laser heating techniques to convert glassy carbon into “quenchable amorphous diamond”, and recover it to ambient conditions. Our X-ray diffraction, high-resolution transmission electron microscopy and electron energy-loss spectroscopy experiments on the recovered sample and computer simulations confirm its tetrahedral amorphous structure and complete sp 3 bonding. This transparent quenchable amorphous diamond has, to our knowledge, the highest density among amorphous carbon materials, and shows incompressibility comparable to crystalline diamond.

High‐Pressure Geophysical Properties of Fcc Phase FeHX

“…The reaction sequence previously described by Narygina et al () (Fe + C n H 2n+2 → 2Fe 3 C + 3H 2 → 6FeH + 2C) was not consistently observed, as no attempt was made to evaluate this transformation with low temperature (<1,500 K) diffraction. Additionally, the obtained phase assemblage (supporting information Table S1) did not consistently indicate the presence of diamond, likely due to diamond's poor diffraction properties, particularly when synthesized at low temperatures (Zeng et al, ). Though the formation of fcc FeH X could be confirmed using at minimum the (111) and (200) peaks, the presence of iron carbide was not detected via XRD.…”

Pressure-induced tuning of lattice distortion in a high-entropy oxide

“…We speculate that the crystal-to-crystal transitions may be hindered by a large energy barrier in this system, therefore, we also performed in situ laser heating XRD measurements at highpressure (more experimental details can be found in ref. 46 ) on the (Ce,La,Pr,Sm,Y)O HEO ( Supplementary Fig. 4).…”

MXene‐Based Composites: Synthesis and Applications in Rechargeable Batteries and Supercapacitors

“…The elemental carbon-based materials adopt many forms, such as amorphous, graphite, [128] diamond, [129] etc. Carbon-based materials show a number of excellent physical and chemical properties, such as good electronic optical and mechanical properties.…”