使用高温烧结氧化铝陶瓷温度梯度法合成宝石级金刚石

在高温高压下采用温度梯度法合成宝石级金刚石，采用高纯氧化铝粉烧结制备氧化铝陶瓷腔体保温材料，研究不同烧结温度下的氧化铝陶瓷性能以及用作腔体保温材料时对应的晶体生长情况。研究表明:随着氧化铝烧结温度的提升，氧化铝陶瓷的密度增大，显气孔率降低，所对应的晶体生长速度增大，晶体内夹杂物减少。1 650 ℃烧结4 h时，氧化铝陶瓷相对密度为97%，显气孔率为0.05%；用于保温腔体材料时，可制得质量为0.4 g(2 ct)、生长速度达4.0 mg/h的基本不含任何夹杂物的高品级金刚石。 

Synthesis of gem grade diamond by temperature gradient method using high temperature sintered alumina ceramics

Gem diamond was synthesized by temperature gradient method under high temperature and high pressure. Alumina ceramics used as insulation chamber were prepared by sintering high purity alumina powder at different temperature. The results show that with the increase of sintering temperature, the density of alumina ceramics increases, the apparent porosity decreases, the corresponding crystal growth rate increases, and the inclusions in the crystal decrease. The relative density of alumina ceramics is 97% and the apparent porosity is 0.05% when sintered at 1 650 ℃ for 4h. The high-grade diamond without any inclusions, weighing 0.40 g (2 ct) and growing at a speed of 4.0 mg/h was prepared.