Search

To improve the performance of PcBN composites prepared under high temperature and high pressure, mixed cBN particle sizes ranging from 0 to 0.5 μm and 0.5 to 1.0 μm were used as the raw material, Al-Ti-Al2O3 was used as the binder and the carbon nanotubes with different contents were added. The PcBN composites were prepared by sintering under high temperature and high pressure conditions. The effect of carbon nanotube content on the structure and properties of PcBN composites was investigated. The results show that there is no chemical reaction between PcBN and carbon nanotubes after the addition of carbon nanotubes, and the carbon nanotubes exist in the form of reinforcement inside the composite. The composite material is relatively dense, and the relative density of PcBN increases first and then decreases with the addition of carbon nanotubes. When the mass fraction of carbon nanotubes added is 1.5%, the relative density of PcBN reaches its maximum value of 97.9%, while PcBN has the maximum microhardness and fracture toughness of 3 892 HV and 6.82 MPa·m1/2, respectively. When the mass fraction of carbon nanotubes added is 1.0%, PcBN has the maximum bending strength and wear ratio, which are 584 MPa and 6 873 MPa, respectively. The pull-out and bridging effects of carbon nanotubes improve the mechanical properties of PcBN composites.

Copyright of Diamond & Abrasives Engineering is the property of Zhengzhou Research Institute for Abrasives & Grinding and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Phases and pressure–temperature (P–T) relationship of CH4–H2O binary system were observed in situ by diamond anvil cell (DAC) and Raman spectroscopy under various temperature and pressure. The system shows three states: (1) State I: methane in low density and immiscible with water at 75–150°C and 80–189MPa; (2) State II: methane in high density and immiscible with water at 175–220°C and 265–303MPa; and (3) State III: methane dissolved in water at above 225°C and 303MPa. Pressure drops by about 100MPa in the system when the state transforms from II to III, indicating negative excess volume during the transition. Raman spectra of methane show discontinuity between State II and III, indicating multi-component interactions and system property variations during the phase transition. [Copyright &y& Elsevier]