Dependence of Growing High-Quality Gem Diamonds on GrowthRates by Temperature Gradient Method

Abstract

Using the temperature gradient method under high pressure and hightemperature, we investigate the dependence of growing high-quality gemdiamond crystals on the growth rates. It is found that the lower thegrowth rate of gem diamond crystals, the larger the temperature rangeof growing high-quality gem diamond crystals, and the easier thecontrol of temperature. In particular, when growing gem diamonds undera very-low growth rate, the temperature range of growing high-qualitygem diamonds can extend from a low-temperature pure {100} growthregion to {100} +{111} growth regions, and finally to ahigh-temperature only-{111}-growth region. When growing gem diamondsunder a high growth rate, some metal inclusions in the growing diamondsalways exist near the seeds, no matter whether the growth temperatureis high or low. This result is not in agreement with the result ofSumitomo Electric Corporation in Japan.