Refraction of Hydrosols Containing Diamond/Amorphous Carbon Composite Particles

Refractometric studies of hydrosols containing diamond nanoparticles have been carried out in this work. The samples for the study have been obtained from a statically synthesized diamond powder preliminarily subjected to standard purification by washing with strong acids and sonication. After additional repeated washing, centrifugation, sonication, and settling for a month, samples, whose particles contained different fractions of amorphous carbon, have been obtained. The particle size in the obtained samples was smaller than 100 nm. To analyze the data of refractometric measurements, equations have been derived that make it possible to determine the fraction of amorphous carbon in the particles and to calculate the thickness of its layer on the particle surface from the results of studying the refractive index and density of the sols of diamond particles. The data of the refractometric studies have been used to determine the ratios between the fractions of crystalline diamond and amorphous carbon in the particles. The performed studies have shown that the refractometric analysis of particle composition can be used to control the quality of industrially produced nanodiamonds.