在压力为5.5—6.2 GPa,温度为1280—1450℃的条件下,利用温度梯度法详细考察了氮氢协同掺杂对{100}晶面生长宝石级金刚石的影响.实验结果表明伴随合成腔体内氮、氢浓度的升高,合成条件明显升高,金刚石生长V形区间上移;晶体的红外光谱中...在压力为5.5—6.2 GPa,温度为1280—1450℃的条件下,利用温度梯度法详细考察了氮氢协同掺杂对{100}晶面生长宝石级金刚石的影响.实验结果表明伴随合成腔体内氮、氢浓度的升高,合成条件明显升高,金刚石生长V形区间上移;晶体的红外光谱中与氮相关的吸收峰急剧增强,氮含量可达2000 ppm,同时位于2850 cm 1和2920 cm 1对应于sp3杂化C—H键的对称伸缩振动和反对称伸缩振动的红外特征峰逐渐增强,表明晶体中既有高的氮含量,同时又含有氢.对晶体进行电镜扫描发现,氮氢协同掺杂对晶体形貌影响明显,出现拉长的{111}面,且晶体表面上有三角形生长纹理.拉曼测试表明,晶体的峰位向高频偏移、半峰宽变大,说明氮、氢杂质的进入对晶体内部产生了应力.本文成功地以{100}晶面为生长面合成出高氮含氢宝石级金刚石单晶,在探究氮氢共存环境下金刚石生长特性的同时,也可为理解天然金刚石的形成机理提供帮助.展开更多
The high pressure and high temperature（HPHT） method is successfully used to synthesize jadeite in a temperature range of 1000℃–1400℃ under a pressure of 3.5 GPa. The initial raw materials are Na2SiO3·9H2O an...The high pressure and high temperature（HPHT） method is successfully used to synthesize jadeite in a temperature range of 1000℃–1400℃ under a pressure of 3.5 GPa. The initial raw materials are Na2SiO3·9H2O and Al2（SiO3）3.Through the HPHT method, the amorphous glass material is entirely converted into crystalline jadeite. We can obtain the good-quality jadeite by optimizing the reaction pressure and temperature. The measurements of x-ray diffraction（XRD）,scanning electron microscopy（SEM）, Fourier-transform infrared（FTIR） and Raman scattering indicate that the properties of synthesized jadeite at 1260℃ under 3.5 GPa are extremely similar to those of the natural jadeite. What is more, the results will be valuable for understanding the formation process of natural jadeite. This work also reveals the mechanism for metamorphism of magma in the earth.展开更多
The properties of urea under high pressure and high temperature(HPHT) are studied using a China-type large volume cubic high-presentation apparatus(CHPA)(SPD-6 × 600).The samples are characterized by scanning ele...The properties of urea under high pressure and high temperature(HPHT) are studied using a China-type large volume cubic high-presentation apparatus(CHPA)(SPD-6 × 600).The samples are characterized by scanning electron microscopy(SEM), x-ray diffraction(XRD), and Raman spectroscopy.By directly observing the macroscopic morphology of urea with SEM, it is confirmed that the melting point of urea rises with the increase of pressure.The XRD patterns of urea residues derived under different pressures show that the thermal stability of urea also increases with the increase of pressure.The XRD pattern of the urea residue confirms the presence of C3H5N5O(ammeline) in the residue.A new peak emerges at 21.80°, which is different from any peak of all urea pyrolysis products under normal pressure.A more pronounced peak appears at 708 cm^-1 in the Raman spectrum, which is produced by C-H off-plane bending.It is determined that the urea will produce a new substance with a C-H bond under HPHT, and the assessment of this substance requires further experiments.展开更多
文摘在压力为5.5—6.2 GPa,温度为1280—1450℃的条件下,利用温度梯度法详细考察了氮氢协同掺杂对{100}晶面生长宝石级金刚石的影响.实验结果表明伴随合成腔体内氮、氢浓度的升高,合成条件明显升高,金刚石生长V形区间上移;晶体的红外光谱中与氮相关的吸收峰急剧增强,氮含量可达2000 ppm,同时位于2850 cm 1和2920 cm 1对应于sp3杂化C—H键的对称伸缩振动和反对称伸缩振动的红外特征峰逐渐增强,表明晶体中既有高的氮含量,同时又含有氢.对晶体进行电镜扫描发现,氮氢协同掺杂对晶体形貌影响明显,出现拉长的{111}面,且晶体表面上有三角形生长纹理.拉曼测试表明,晶体的峰位向高频偏移、半峰宽变大,说明氮、氢杂质的进入对晶体内部产生了应力.本文成功地以{100}晶面为生长面合成出高氮含氢宝石级金刚石单晶,在探究氮氢共存环境下金刚石生长特性的同时,也可为理解天然金刚石的形成机理提供帮助.
基金supported by the National Natural Science Foundation of China(Grant Nos.51172089 and 51171070)the Graduate Innovation Fund of Jilin University,China(Grant No.2016065)
文摘The high pressure and high temperature（HPHT） method is successfully used to synthesize jadeite in a temperature range of 1000℃–1400℃ under a pressure of 3.5 GPa. The initial raw materials are Na2SiO3·9H2O and Al2（SiO3）3.Through the HPHT method, the amorphous glass material is entirely converted into crystalline jadeite. We can obtain the good-quality jadeite by optimizing the reaction pressure and temperature. The measurements of x-ray diffraction（XRD）,scanning electron microscopy（SEM）, Fourier-transform infrared（FTIR） and Raman scattering indicate that the properties of synthesized jadeite at 1260℃ under 3.5 GPa are extremely similar to those of the natural jadeite. What is more, the results will be valuable for understanding the formation process of natural jadeite. This work also reveals the mechanism for metamorphism of magma in the earth.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51772120,11604246,51872112,and 11804305)the Project of Jilin Science and Technology Development Plan,China(Grant No.20180201079GX)
文摘The properties of urea under high pressure and high temperature(HPHT) are studied using a China-type large volume cubic high-presentation apparatus(CHPA)(SPD-6 × 600).The samples are characterized by scanning electron microscopy(SEM), x-ray diffraction(XRD), and Raman spectroscopy.By directly observing the macroscopic morphology of urea with SEM, it is confirmed that the melting point of urea rises with the increase of pressure.The XRD patterns of urea residues derived under different pressures show that the thermal stability of urea also increases with the increase of pressure.The XRD pattern of the urea residue confirms the presence of C3H5N5O(ammeline) in the residue.A new peak emerges at 21.80°, which is different from any peak of all urea pyrolysis products under normal pressure.A more pronounced peak appears at 708 cm^-1 in the Raman spectrum, which is produced by C-H off-plane bending.It is determined that the urea will produce a new substance with a C-H bond under HPHT, and the assessment of this substance requires further experiments.
