Influence mechanism of temperature fluctuation on the growth of adjunct diamond under HPHT conditions

The growth of adjunct crystals significantly impacts the quality of synthetic diamonds, with temperature fluctuations being the primary cause. This study investigates the influence mechanism of temperature fluctuations on the growth of synthetic diamond crystals under high temperature and high pressure (HPHT) conditions through a combination of experimental and numerical simulation approaches. Numerical simulations reveal that ambient temperature variations directly affect the temperature field within the cavity, subsequently altering the carbon solubility in the metal catalyst. Over time, the synthesis process, influenced by varying solubility due to temperature changes, leads to secondary diamond growth, resulting in the formation of adjunct diamonds. This study offers a theoretical explanation of how temperature fluctuations affect the growth of these crystals, providing valuable theoretical guidance for the experimental synthesis of high-quality diamonds in industrial settings.