Industrial diamonds grown in Ni70Mn25Co5-graphite-sulfur system under HPHT

• 来源期刊: 中国物理B（英文版）
• 关键词: sulfur diamond morphology MnS
• 年，卷（期）: 2009,（1）
• 页码范围: 333-338
• 页数: 6页
• 语种: 英文

摘要

This paper reports that diamond single crystals were synthesized from sulfur-added Ni70Mn25Co5 +C system under high pressure and high temperature (HPHT). It was found that additive sulfur had inhibited the nucleation and growth of diamond to some extent. X-ray diffraction of the collected sample indicated that under the synthesis conditions, a new compound MnS had been formed through the reaction of additive sulfur with manganese in the catalyst. The MnS has a fcc structure, and its average crystal size was about 30 nm. By scanning electron microscope, the {111} surface of diamond was found to be flat, while there was usually a large deprcssion on the central region of {100}. Further observation showed that there were many small upside-down pyramidal pits in the expression. The results of x-ray photoelectron spectroscopy shows that MnS can only be detected in the depression in the range of detection precision. It was inferred that MnS had been dissolved in the melted alloy during the growth experiment, and precipitated in the sequent qucnching process.