Comparison of morphological and structural characteristics of nanopowder particles obtained by natural diamond grinding and detonation synthesis

Abstract

The study covers specific features of morphological and structural characteristics exhibited by nanopowder particles obtained by grinding a massive natural diamond and the method of detonation synthesis. High-resolution transmission and scanning electron microscopy, small-angle X-ray scattering demonstrated that natural diamond nanopowder particles obtained by grinding have a wider range of sizes and a plated appearance, unlike detonation synthesis nanopowders consisting of similar in size and isometric particles. X-ray diffraction analysis and Raman spectroscopy used in addition to the methods mentioned above showed that the structure of nanodiamond particles obtained from natural diamond is similar to the structure of a detonation synthesis nanodiamond. Each particle of natural nanopowder, as well as detonation synthesis nanodiamond, consists of a diamond core with a crystal lattice related to the cubic system and a shell containing mainly non-diamond carbon forms with sp 2 hybridization having a complex structure. The average particle size of nanopowders obtained from natural diamond and using detonation synthesis studied by three methods including BET showed results that are in satisfactory agreement with each other. The average nanoparticle size is about 24 nm for natural diamond powder and close to 5.6 nm for UDA-S-GO detonation synthesis nanodiamonds produced by the Federal Research and Production Center «Altai». An insignificant increase in the interatomic distances in diamond nanocrystals compared with a massive diamond crystal was shown experimentally. The study and analysis of a numerous images of natural and detonation synthesis diamond nanocrystals obtained by high-resolution transmission electron microscopy made it possible to establish that the most frequent defects in nanodiamonds are dislocations and point defects.