Study of high-pressure sintering behavior of cBN composites starting with cBN–Al mixtures

2008 ◽  
Vol 23 (9) ◽  
pp. 2366-2372 ◽  
Author(s):  
Yongjun Li ◽  
Sicheng Li ◽  
Ran Lv ◽  
Jiaqian Qin ◽  
Jian Zhang ◽  
...  
Keyword(s):  
High Pressure ◽  
Sintering Temperature ◽  
Cubic Boron Nitride ◽  
Sintering Behavior ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
High Pressure Sintering

Cubic boron nitride (cBN) composites starting with cBN–Al mixtures were sintered on WC-16 wt% Co substrates under static high pressure of 5.0 GPa and at temperatures of 800–1400 °C 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 1400 °C. The reactions between cBN and Al started to occur at about 900 °C, and the reaction products strongly depended on the Al content, sintering temperature, and Co diffusion from the substrates according to the x-ray diffraction (XRD) observations. The high pressure and high temperature in situ resistance measurement indicated that the reactions between cBN and Al could be completed in about 90 s when the temperature was higher than ∼1200 °C at high pressure. The cBN composite sintered at 1200 °C from a cBN–15 wt% Al mixture showed the best cutting performance.

scholarly journals Pressure-induced Jahn-Teller Switch in the Homoleptic Hybrid Perovskite [(CH3)2NH2]Cu(HCOO)3: Orbital Reordering by Unconventional Degrees of Freedom

2021 ◽  
Author(s):  
Rebecca Scatena ◽  
Michał Andrzejewski ◽  
Roger D Johnson ◽  
Piero Macchi
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Coordination Polymer ◽  
Degrees Of Freedom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Perovskite ◽  
Jahn Teller

Through in-situ, high-pressure x-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3)2NH2]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct...

PHASE TRANSITION IN LAYERED PEROVSKITE LIKE MANGANATE Ca3Mn2O7 UNDER HIGH PRESSURE

2001 ◽  
Vol 15 (18) ◽  
pp. 2491-2497 ◽  
Author(s):  
J. L. ZHU ◽  
L. C. CHEN ◽  
R. C. YU ◽  
F. Y. LI ◽  
J. LIU ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
The Other ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Diamond Anvil

In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca 3 Mn 2 O 7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca 3 Mn 2 O 7 underwent two phase transitions under pressures in the range of 0~35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.

scholarly journals In situ observation of phase changes of a silica-supported cobalt catalyst for the Fischer–Tropsch process by the development of a synchrotron-compatible in situ/operando powder X-ray diffraction cell

2018 ◽  
Vol 25 (6) ◽  
pp. 1673-1682 ◽  
Author(s):  
Adam S. Hoffman ◽  
Joseph A. Singh ◽  
Stacey F. Bent ◽  
Simon R. Bare
Keyword(s):  
High Pressure ◽  
Elevated Pressure ◽  
Phase Changes ◽  
In Situ Observation ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
X Ray ◽  
And Performance ◽  
Co Nanoparticles

In situ characterization of catalysts gives direct insight into the working state of the material. Here, the design and performance characteristics of a universal in situ synchrotron-compatible X-ray diffraction cell capable of operation at high temperature and high pressure, 1373 K, and 35 bar, respectively, are reported. Its performance is demonstrated by characterizing a cobalt-based catalyst used in a prototypical high-pressure catalytic reaction, the Fischer–Tropsch synthesis, using X-ray diffraction. Cobalt nanoparticles supported on silica were studied in situ during Fischer–Tropsch catalysis using syngas, H2 and CO, at 723 K and 20 bar. Post reaction, the Co nanoparticles were carburized at elevated pressure, demonstrating an increased rate of carburization compared with atmospheric studies.

scholarly journals In-situ high-pressure x-ray diffraction study of zinc ferrite nanoparticles

2016 ◽  
Vol 56 ◽  
pp. 68-72 ◽  
Author(s):  
S. Ferrari ◽  
R.S. Kumar ◽  
F. Grinblat ◽  
J.C. Aphesteguy ◽  
F.D. Saccone ◽  
...  
Keyword(s):  
High Pressure ◽  
Diffraction Study ◽  
Zinc Ferrite ◽  
Ferrite Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals In Situ High-Pressure X-ray Diffraction and Raman Spectroscopy Study of Ti3C2Tx MXene

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Luxi Zhang ◽  
Weitao Su ◽  
Yanwei Huang ◽  
He Li ◽  
Li Fu ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Spectroscopy Study ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals The Viscosity and Atomic Structure of Volatile-Bearing Melilititic Melts at High Pressure and Temperature and the Transport of Deep Carbon

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 267 ◽  
Author(s):  
Vincenzo Stagno ◽  
Veronica Stopponi ◽  
Yoshio Kono ◽  
Annalisa D’Arco ◽  
Stefano Lupi ◽  
...  
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Atomic Structure ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
High Pressure And Temperature ◽  
X Ray ◽  
Falling Sphere ◽  
Basaltic Melts

Understanding the viscosity of mantle-derived magmas is needed to model their migration mechanisms and ascent rate from the source rock to the surface. High pressure–temperature experimental data are now available on the viscosity of synthetic melts, pure carbonatitic to carbonate–silicate compositions, anhydrous basalts, dacites and rhyolites. However, the viscosity of volatile-bearing melilititic melts, among the most plausible carriers of deep carbon, has not been investigated. In this study, we experimentally determined the viscosity of synthetic liquids with ~31 and ~39 wt% SiO2, 1.60 and 1.42 wt% CO2 and 5.7 and 1 wt% H2O, respectively, at pressures from 1 to 4.7 GPa and temperatures between 1265 and 1755 °C, using the falling-sphere technique combined with in situ X-ray radiography. Our results show viscosities between 0.1044 and 2.1221 Pa·s, with a clear dependence on temperature and SiO2 content. The atomic structure of both melt compositions was also determined at high pressure and temperature, using in situ multi-angle energy-dispersive X-ray diffraction supported by ex situ microFTIR and microRaman spectroscopic measurements. Our results yield evidence that the T–T and T–O (T = Si,Al) interatomic distances of ultrabasic melts are higher than those for basaltic melts known from similar recent studies. Based on our experimental data, melilititic melts are expected to migrate at a rate ~from 2 to 57 km·yr−1 in the present-day or the Archaean mantle, respectively.

High-pressure study of a nanostructured SnSe1−xSx (x = 0.5) solid solution by in-situ X-ray diffraction and ab-initio calculations

2019 ◽  
Vol 792 ◽  
pp. 536-542
Author(s):  
Larissa da Silva Marques ◽  
Joelma Maria de Oliveira Ferreira ◽  
Querem Hapuque Félix Rebelo ◽  
Angsula Ghosh ◽  
Daniela Menegon Trichês ◽  
...  
Keyword(s):  
Solid Solution ◽  
High Pressure ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure Study
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