A regrown composite fiber was synthesized during the sintering of diamond under high pressure 5.8 GPa and high temperature 1500℃for 1 min,using 3wt%MWCNTs as additive.SEM observation of the fiber after alkali and aci...A regrown composite fiber was synthesized during the sintering of diamond under high pressure 5.8 GPa and high temperature 1500℃for 1 min,using 3wt%MWCNTs as additive.SEM observation of the fiber after alkali and acid treatment revealed that the outer layer of the fiber is composed of nano-polycrystalline diamond.EDS,XPS,XRD and Raman spectrum analysis further identified that the fiber is composed of MWCNTs in the inner part and nano-polycrystalline diamond in the out layer.It is proposed that the untransformed MWCNTs may act as a template for the regrown outer layer of nano diamond fiber under high pressure and high temperature.展开更多
The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 ℃ using the RheoChan 7400 Rheometer.The experimental ...The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 ℃ using the RheoChan 7400 Rheometer.The experimental results show that the apparent viscosity,plastic viscosity and yield point decrease with the increase of temperature,and increase with the increase of pressure.The effect of pressure on the apparent viscosity,plastic viscosity and yield point is considerable at ambient temperature.However,this effect gradually reduces with the increase of temperature.The major factor influencing the rheological properties of oil-based drilling fluids is temperature instead of pressure in the deep sections of oil wells.On the basis of numerous experiments,the model for predict the apparent viscosity,plastic viscosity and yield point of oil-based drilling fluids at high temperature and pressure was established using the method of regressive analysis.It is confirmed that the calculated data are in good agreement with the measured data,and the correlation coefficients are more than 0.98.The model is convenient for use and suitable for the application in drilling operations.展开更多
The effects of preheating temperature and W powder size on the Self propagating High temperature Synthesis(SHS) of Ti W C system were studied. Preheated mixtures and the decrease of W powder size can accelerate the fo...The effects of preheating temperature and W powder size on the Self propagating High temperature Synthesis(SHS) of Ti W C system were studied. Preheated mixtures and the decrease of W powder size can accelerate the formation of (W,Ti)C powders. The uniphase (W,Ti)C (WC∶TiC=5∶5) powders with 0.32% free carbon were synthesized from Ti, W, C powders by SHS. The powder size of the product was 3～5 μm.展开更多
Experimental and theoretical researches on the doping effect of interface binding state with homologous and heterogeneous dopants(d) in the system of PCD etc,as well as the action of intermediate layers between D /d a...Experimental and theoretical researches on the doping effect of interface binding state with homologous and heterogeneous dopants(d) in the system of PCD etc,as well as the action of intermediate layers between D /d at superhigh pressure and high temperature(HP-HT) are reported in this paper.展开更多
Cubic boron nitride(CBN) composites starting with CBN-Al mixtures were sintered on WC-16 wt%Co substrate under static high pressure of 5.0 GPa at temperatures of 800 to 1 400℃for 30 min.Vickers hardness of the sinter...Cubic boron nitride(CBN) composites starting with CBN-Al mixtures were sintered on WC-16 wt%Co substrate under static high pressure of 5.0 GPa at temperatures of 800 to 1 400℃for 30 min.Vickers hardness of the sintered samples increased with increasing CBN content and the highest hardness of 32.7 GPa was achieved for the CBN-5 wt%Al specimens sintered at 1 400℃.The reactions between CBN and Al started to occur at about 900℃and the reaction products strongly depended on the Al content,sintering temperature and Co diffused from the substrates according to the x-ray diffraction(XRD) observations.The CBN composite sintered at 1 200℃from a CBN-15 wt%Al mixture showed the best cutting performance.展开更多
Lonsdaleite,also known as hexagonal diamond,is an allotrope of carbon with a hexagonal crystal structure,which was discovered in the nanostructure of the Canyon Diablo meteorite.Theoretical calculations have shown tha...Lonsdaleite,also known as hexagonal diamond,is an allotrope of carbon with a hexagonal crystal structure,which was discovered in the nanostructure of the Canyon Diablo meteorite.Theoretical calculations have shown that this structure gives it exceptional physical properties that exceed those of cubic diamond,making it highly promising for groundbreaking applications in superhard cutting tools,wide-bandgap semiconductor devices,and materials for extreme environments.As a result,the controllable synthesis of hexagonal diamond has emerged as a cutting-edge research focus in materials science.This review briefly outlines the progress in this area,with a focus on the mechanisms governing its key synthesis conditions,its intrinsic physical properties,and its potential applications in various fields.展开更多
传统的水岩反应实验中,流体在高温高压条件下发生淋滤反应之后,一些物质很容易在冷却过程中发生二次沉淀或吸附,从而影响实验结果的准确性。人工合成流体包裹体技术能在高温高压条件下对流体进行原位取样,再通过激光剥蚀电感耦合等离子...传统的水岩反应实验中,流体在高温高压条件下发生淋滤反应之后,一些物质很容易在冷却过程中发生二次沉淀或吸附,从而影响实验结果的准确性。人工合成流体包裹体技术能在高温高压条件下对流体进行原位取样,再通过激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)进行成分分析,直接获得高温流体的物质组成,可以有效避免这一问题。本研究模拟兰坪地区盆地卤水(NaCl/NaCl+CaCl_(2))与基底岩石(三叠纪辉绿岩、二叠系岩屑灰岩和中三叠统凝灰岩)在高温高压条件下(200℃、10 MPa)发生水岩反应的过程,通过方解石人工合成流体包裹体技术,研究水岩反应对流体成分的影响,探讨流体中成矿元素的来源,以及与盆地内密西西比河谷型(Mississippi Valley-type,MVT)铅锌矿床在成因上的关系。显微测温表明,初始流体为3 m NaCl+0.15 m CaCl_(2)体系的人工合成流体包裹体的冰点温度介于-13.6~-11.4℃之间,初始流体为3 m NaCl体系的合成包裹体的冰点温度介于-11.8~-10.7℃之间,NaCl体系合成包裹体的冰点温度高于NaCl+CaCl_(2)体系的冰点温度,表明人工合成的包裹体流体组分与初始流体组分一致。结合显微测温分析及单个流体包裹体的LA-ICP-MS原位成分分析测试,证实以方解石为寄主矿物合成水岩反应流体包裹体的实验方法在低温流体-岩石相互作用模拟领域具有广阔的应用前景。展开更多
基金Supported by the National Natural Science Foundation of China(No.50342017)by the Natural Science Foundation of Beijing(No.2042019)
文摘A regrown composite fiber was synthesized during the sintering of diamond under high pressure 5.8 GPa and high temperature 1500℃for 1 min,using 3wt%MWCNTs as additive.SEM observation of the fiber after alkali and acid treatment revealed that the outer layer of the fiber is composed of nano-polycrystalline diamond.EDS,XPS,XRD and Raman spectrum analysis further identified that the fiber is composed of MWCNTs in the inner part and nano-polycrystalline diamond in the out layer.It is proposed that the untransformed MWCNTs may act as a template for the regrown outer layer of nano diamond fiber under high pressure and high temperature.
基金Project(50574061) supported by the National Natural Science Foundation of ChinaProject(IRT0411) supported by the Changjiang Scholars and Innovative Research Team,Ministry of Education
文摘The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 ℃ using the RheoChan 7400 Rheometer.The experimental results show that the apparent viscosity,plastic viscosity and yield point decrease with the increase of temperature,and increase with the increase of pressure.The effect of pressure on the apparent viscosity,plastic viscosity and yield point is considerable at ambient temperature.However,this effect gradually reduces with the increase of temperature.The major factor influencing the rheological properties of oil-based drilling fluids is temperature instead of pressure in the deep sections of oil wells.On the basis of numerous experiments,the model for predict the apparent viscosity,plastic viscosity and yield point of oil-based drilling fluids at high temperature and pressure was established using the method of regressive analysis.It is confirmed that the calculated data are in good agreement with the measured data,and the correlation coefficients are more than 0.98.The model is convenient for use and suitable for the application in drilling operations.
文摘The effects of preheating temperature and W powder size on the Self propagating High temperature Synthesis(SHS) of Ti W C system were studied. Preheated mixtures and the decrease of W powder size can accelerate the formation of (W,Ti)C powders. The uniphase (W,Ti)C (WC∶TiC=5∶5) powders with 0.32% free carbon were synthesized from Ti, W, C powders by SHS. The powder size of the product was 3～5 μm.
文摘Experimental and theoretical researches on the doping effect of interface binding state with homologous and heterogeneous dopants(d) in the system of PCD etc,as well as the action of intermediate layers between D /d at superhigh pressure and high temperature(HP-HT) are reported in this paper.
文摘Cubic boron nitride(CBN) composites starting with CBN-Al mixtures were sintered on WC-16 wt%Co substrate under static high pressure of 5.0 GPa at temperatures of 800 to 1 400℃for 30 min.Vickers hardness of the sintered samples increased with increasing CBN content and the highest hardness of 32.7 GPa was achieved for the CBN-5 wt%Al specimens sintered at 1 400℃.The reactions between CBN and Al started to occur at about 900℃and the reaction products strongly depended on the Al content,sintering temperature and Co diffused from the substrates according to the x-ray diffraction(XRD) observations.The CBN composite sintered at 1 200℃from a CBN-15 wt%Al mixture showed the best cutting performance.
基金the National Natural Science Foundation of China(12274170 and 52225203)。
文摘Lonsdaleite,also known as hexagonal diamond,is an allotrope of carbon with a hexagonal crystal structure,which was discovered in the nanostructure of the Canyon Diablo meteorite.Theoretical calculations have shown that this structure gives it exceptional physical properties that exceed those of cubic diamond,making it highly promising for groundbreaking applications in superhard cutting tools,wide-bandgap semiconductor devices,and materials for extreme environments.As a result,the controllable synthesis of hexagonal diamond has emerged as a cutting-edge research focus in materials science.This review briefly outlines the progress in this area,with a focus on the mechanisms governing its key synthesis conditions,its intrinsic physical properties,and its potential applications in various fields.
文摘传统的水岩反应实验中,流体在高温高压条件下发生淋滤反应之后,一些物质很容易在冷却过程中发生二次沉淀或吸附,从而影响实验结果的准确性。人工合成流体包裹体技术能在高温高压条件下对流体进行原位取样,再通过激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)进行成分分析,直接获得高温流体的物质组成,可以有效避免这一问题。本研究模拟兰坪地区盆地卤水(NaCl/NaCl+CaCl_(2))与基底岩石(三叠纪辉绿岩、二叠系岩屑灰岩和中三叠统凝灰岩)在高温高压条件下(200℃、10 MPa)发生水岩反应的过程,通过方解石人工合成流体包裹体技术,研究水岩反应对流体成分的影响,探讨流体中成矿元素的来源,以及与盆地内密西西比河谷型(Mississippi Valley-type,MVT)铅锌矿床在成因上的关系。显微测温表明,初始流体为3 m NaCl+0.15 m CaCl_(2)体系的人工合成流体包裹体的冰点温度介于-13.6~-11.4℃之间,初始流体为3 m NaCl体系的合成包裹体的冰点温度介于-11.8~-10.7℃之间,NaCl体系合成包裹体的冰点温度高于NaCl+CaCl_(2)体系的冰点温度,表明人工合成的包裹体流体组分与初始流体组分一致。结合显微测温分析及单个流体包裹体的LA-ICP-MS原位成分分析测试,证实以方解石为寄主矿物合成水岩反应流体包裹体的实验方法在低温流体-岩石相互作用模拟领域具有广阔的应用前景。
