Synthesis and characterization of diamonds using C3H5N3O as an organic additive under high pressure and high temperature

Abstract

In the NiMnCo–C system, diamond single crystals have been successfully synthesized by adding C₃H₅N₃O as an organic additive under 5.5–6.2 GPa and 1280–1320 °C. The synthesized diamonds are initially characterized using OM, SEM, FTIR, Raman, XPS and powder XRD. With the increase of the C₃H₅N₃O content, the color of diamonds changes from light yellow to green. The FTIR spectra of the diamond synthesized indicate that its nitrogen concentration increases with the increase of the C₃H₅N₃O additive. The typical oxygen and hydrogen related peaks appear and the absorption intensity increases with addition of C₃H₅N₃O. The Raman spectrum and XRD spectrum show synthesized diamonds with a good quality phase of crystallization. The XPS results again confirmed that oxygen, hydrogen and nitrogen related impurities exist in the diamond. It is meaningful to provide reference data to further recognize the composition of the natural diamond growth environment.