Growth characteristics of type IIa large single crystal diamond with Ti/Cu as nitrogen getter in FeNi–C system  

作　　者：Ming-Ming Guo Shang-Sheng Li Mei-Hua Hu Tai-Chao Su Jun-Zuo Wang Guang-Jin Gao Yue You Yuan Nie 郭明明;李尚升;胡美华;宿太超;王君卓;高广进;尤悦;聂媛(Henan Key Laboratory of Materials on Deep-Earth Engineering,School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;Jiaozuo Engineering Technology Research Center of Advanced Functional Materials Preparation under High Pressure,Jiaozuo 454003,China)

机构地区：[1]Henan Key Laboratory of Materials on Deep-Earth Engineering,School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China [2]Jiaozuo Engineering Technology Research Center of Advanced Functional Materials Preparation under High Pressure,Jiaozuo 454003,China

出　　处：《Chinese Physics B》2020年第1期457-462,共6页中国物理B（英文版）

基　　金：Project supported by the Natural Science Foundation of Henan Province of China(Grant No.182300410279);the Key Science and Technology Research Project of Henan Province of China(Grant No.182102210311);the Key Scientific Research Project in Colleges and Universities of Henan Province of China(Grant Nos.18A430017 and 20B140009);the Fundamental Research Funds for the Universities of Henan Province of China(Grant No.NSFRF180408);the Fund for the Innovative Research Team(in Science and Technology)in the University of Henan Province of China(Grant No.19IRTSTHN027)

摘　　要：High-quality type IIa large diamond crystals are synthesized with Ti/Cu as nitrogen getter doped in an FeNi–C system at temperature ranging from 1230℃to 1380℃and at pressure 5.3–5.9 GPa by temperature gradient method.Different ratios of Ti/Cu are added to the Fe Ni–C system to investigate the best ratio for high-quality type IIa diamond.Then,the different content of nitrogen getter Ti/Cu(Ti:Cu=4:3)is added to this synthesis system to explore the effect on diamond growth.The macro and micro morphologies of synthesized diamonds with Ti/Cu added,whose nitrogen concentration is determined by Fourier transform infrared(FTIR),are analyzed by optical microscopy(OM)and scanning electron microscopy(SEM),respectively.It is found that the inclusions in the obtained crystals are minimal when the Ti/Cu ratio is 4:3.Furthermore,the temperature interval for diamond growth becomes narrower when using Ti as the nitrogen getter.Moreover,the lower edge of the synthesis temperature of type IIa diamond is 25℃higher than that of type Ib diamond.With the increase of the content of Ti/Cu(Ti:Cu=4:3),the color of the synthesized crystals changes from yellow and light yellow to colorless.When the Ti/Cu content is 1.7 wt%,the nitrogen concentration of the crystal is less than 1 ppm.The SEM results show that the synthesized crystals are mainly composed by(111)and(100)surfaces,including(311)surface,when the nitrogen getter is added into the synthesis system.At the same time,there are triangular pits and dendritic growth stripes on the crystal surface.This work will contribute to the further research and development of high-quality type IIa diamond.High-quality type IIa large diamond crystals are synthesized with Ti/Cu as nitrogen getter doped in an FeNi–C system at temperature ranging from 1230℃ to 1380℃ and at pressure 5.3–5.9 GPa by temperature gradient method. Different ratios of Ti/Cu are added to the Fe Ni–C system to investigate the best ratio for high-quality type IIa diamond. Then, the different content of nitrogen getter Ti/Cu(Ti : Cu = 4 : 3) is added to this synthesis system to explore the effect on diamond growth. The macro and micro morphologies of synthesized diamonds with Ti/Cu added, whose nitrogen concentration is determined by Fourier transform infrared(FTIR), are analyzed by optical microscopy(OM) and scanning electron microscopy(SEM), respectively. It is found that the inclusions in the obtained crystals are minimal when the Ti/Cu ratio is 4:3. Furthermore, the temperature interval for diamond growth becomes narrower when using Ti as the nitrogen getter.Moreover, the lower edge of the synthesis temperature of type IIa diamond is 25℃ higher than that of type Ib diamond.With the increase of the content of Ti/Cu(Ti : Cu = 4 : 3), the color of the synthesized crystals changes from yellow and light yellow to colorless. When the Ti/Cu content is 1.7 wt%, the nitrogen concentration of the crystal is less than 1 ppm.The SEM results show that the synthesized crystals are mainly composed by(111) and(100) surfaces, including(311)surface, when the nitrogen getter is added into the synthesis system. At the same time, there are triangular pits and dendritic growth stripes on the crystal surface. This work will contribute to the further research and development of high-quality type IIa diamond.

关 键 词：high temperature and high pressure temperature gradient method type IIa diamond 

分 类 号：TB34[一般工业技术—材料科学与工程] O78[理学—晶体学]