硼含量对合成金刚石的颜色和热稳定性的影响

Influence of Boron Content in Diamond on Color and Thermal Stability of Synthetic Diamond

研究了金刚石中硼含量对金刚石的颜色和耐热性能的影响。以石墨和触媒粉末作原料，用硼酸作为添加剂，在高温高压下合成出含硼金刚石。用原子发射光谱定量分析法检测金刚石中硼原子的含量；采用动态空气流条件下的热重和差示扫描量热方法对金刚石进行了热稳定分析，用体视显微镜观察金刚石的颜色。结果表明：合成金刚石的初始氧化温度超过840℃，最高达到920℃；1200℃时，热失重率在58％～94％之间，放热峰值在990℃～1135℃之间；随着硼含量的增加，金刚石的颜色由黄变黑，热稳定性提高。当控制硼元素的含量低于30×10^-6时，可以合成出热稳定性高的黄色透明金刚石。

In order to investigate the influence of boron content in the diamond on the color and thermal stability of diamond, boron-doped diamond was synthesized under high pressure and high temperature, using graphite and alloy catalyst powders as starting materials, and boric acid as addiefives. The boron contents in the diamond crystals were quantitatively measured by the atomic-emitting spectrum method. Further, thermogravimetrie analysis （TGA） and differential scanning calorimetry （DSC） in flowing air were used to analyze thermal stability of synthetic diamond. The colors of synthetic diamond crystals were observed with the help of a stereomieroseope. The results indicate that the synthesized diamond has the initial oxygenation temperatures of over 840 ℃, even up to 920 ℃, and the exothermie summit of approximate 990 ℃, even up to 1135 ℃, and the weight loss from 58% to 94% at 1200 ℃. With the increase of the boron content, the color of the diamond turns from yellow to dark, the thermal stability of diamond gets better. Transparent yellow diamond with good thermal stability can be obtained if the contents of boron element in the diamond are controlled below 30 ppm.