利用不同籽晶面生长优质宝石级金刚石单晶

Growth of High-quality Gem Diamonds with Different Seed Facets

为了研究不同籽晶生长面合成宝石级金刚石单晶(>1 mm),以N iMnCo金属触媒,采用高温高压温度梯度法合成了籽晶{1 0 0}生长面的优质宝石级金刚石单晶(>4 mm),并与以籽晶{1 1 1}作为生长面合成的晶体作了对比分析。结果表明:随着合成温度的升高,用{1 0 0}面生长出的晶体形貌由低温片状逐渐过渡到高温塔状,而用{1 1 1}面生长出的晶体形貌变化趋势则相反;采用籽晶{1 0 0}面或{1 1 1}面生长晶体,无论合成温度高低,包裹体都不容易进入片状晶体内部;只要存在合适的温度梯度,N iMnCo触媒同样适合利用籽晶{1 1 1}面生长优质大尺寸宝石级金刚石(≥4 mm)。因此可以利用该方法寻找物美价廉的新触媒以取代目前价格日益增长的N iMnCo合金。

To study gem-grade diamond crystals （ 〉 1 mm）synthesized on different seed facets, high-quality gem-grade diamond crystal（ 〉4 mm） was synthesized on { 111 } seed facets with NiMnCo as metal solvent using temperature gradient method （TGM） under high pressure and high temperature（ HPHT）, and compared with that grown on { 100 } facet. The results show that in the case of { 100 } , the morphology of crystal changes from low-temperature sheet to high-temperature tower with increasing the synthesized temperature, whereas in the case of {111} the change trend is contrary to {100}. When {111} facet or {111} was used as the growth facet, the sheet-like crystal is more difficult to incorporated for the metal inclusion regardless of synthesized temperature. With NiMnCo metal as solvent, large high-quality gem-grade diamonds can also grow on { 111 } facet with proper temperature gradient. Therefore, this method can be used to seek a cheaper metal solvent to replace expensive NiMnCo alloy for diamond synthesis.