Comparison of Morphological and Structural Characteristics of Nanopowder Particles Fabricated by Grinding Natural Diamond and Detonation Synthesis

Abstract

Specific features of the morphological and structural characteristics of nanopowder particles fabricated by grinding bulk natural diamond and by detonation synthesis are investigated. It is shown by highresolution transmission electron microscopy, scanning electron microscopy, and low-angle X-ray scattering that, in contrast with the detonation synthesis nanopowder, which consists of similar in size and isometrically primary particles, natural diamond particles fabricated by grinding have a broader spread in regards to size and a preferentially platelet form. It is established by the X-ray structural phase analysis and Raman spectroscopy used in addition to above-listed methods that the structure of particles of nanodiamond formed from natural diamond is similar to the structure of detonation-synthesis nanodiamond. Each particle of natural nanopowder, similarly to detonation-synthesis nanodiamond, consists of a diamond core having a crystal lattice of the cubic crystal system and a shell containing mainly nondiamond forms of carbon with sp 2 hybridization with a complex structure. The data on the evaluation of the average particle size of nanopowders of natural diamond and detonation synthesis by three methods, including BET, show results that satisfactorily agree with each other. Herewith, an average particle size of natural powder nanoparticles is close to 24 nm, while that of detonation-synthesis nanodiamonds of the UDA-S-GO brand produced by FRPC Altai is close to 5.6 nm. An insignificant increase in interatomic distances in diamond nanocrystals is revealed when compared with the bulk diamond crystal. The investigation and analysis of numerous images of natural diamond nanocrystals and detonation synthesis nanocrystals formed by high-resolution transmission electron microscopy show that the dislocations and point defects are most often defects in nanodiamonds.