Synthesis of the Nanocomposite Based on Impact Diamonds and Silicon Carbide under Conditions of High Pressure and Temperature

Abstract

The article studies the structure, phase composition and physicomechanical characteristics of the nanocomposite based on impact diamonds. It is shown that the additions of a binder based on SiC and Si lead to reduction of the defectiveness of the nanocomposite and increase in the uniformity of its structure compared to the material without additives. Moreover, increase in the binder content also leads to the inversion of the structure type of the nanocomposite from polycrystalline to matrix. It is established that the addition of amorphous carbon black and boron affects the refinement of the nanocomposite matrix structure due to the formation of secondary finedispersed nanostructured SiC and boron carbide. Preliminary mechanical activation of the reaction mixture leads to structural changes in the synthesized material in comparison with the material obtained without the use of mechanical activation. In this case, the hardness of the samples obtained under comparable synthesis modes increases, which is associated both with the formation of a fine-grained structure of the material and with the phase transformation of lonsdaleite to diamond. An analysis of the microhardness and heat resistance of the obtained samples makes it possible to conclude that the achieved level of physicomechanical parameters of the diamond nanocomposite allows it to be used in a stone-processing tool for treating medium hard rocks.

Keywords

• nanocomposite
• synthesis
• impact diamonds
• high pressure and temperature
• silicon carbide
• mechanical activation