高压物理学报

The Effect of Boron Additives on the Oxidation Rate of Synthetic Diamond Monocrystals

ZHENG Zhou

1992, 6(1): 1-6 . doi: 10.11858/gywlxb.1992.01.001

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Abstract:
By means of molten KNO3 oxidation experiments were conducted on the discs cut from a large synthetic diamond monocrystal. The relative depth of oxidation formed at sector boundaries on oxidized (110) cross-section of the diamond monocrystals (boron-doped and non-boron-doped) were measured with a two-beam interference microscope. The relative oxidation rates between growth sectors were calculated, and were connected with the amount of boron additive in these sectors.

The High Oxygen Pressure Synthesis of Metallic LaCuO3 and the XPS Study on Cu3+ State

ZHOU Jian-Shi

1992, 6(1): 7-14 . doi: 10.11858/gywlxb.1992.01.002

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Abstract:
In this work, on the basis of LaCuO3 synthesized at high oxygen pressure (~6.5 GPa) and temperature (~980 ℃) and of its structure determination, the Cu3+ ion in metallic state was first characterized, and the difference between the metallic and insulator state was studied. The compound of LaCuO3 synthesized in this study is a metallic one which does not show superconductivity until 13 K by resistivity measurements. The XPS measurements show that the Cu2p3/2 core level in LaCuO3 shifts to higher binding energy about 2.6 eV relative to that of Cu2+ in La2CuO4 or CuO, this value is 1.3 eV higher than the relative shift value of Cu2p3/2 in NaCuO2 (insulator) to Cu2+ in CuO. The measurement of Auger line indicates that the modified Auger parameters of LaCuO3 are comparable to CuO but the L3VV Auger-electron kinetic energy shifts by 2.8 eV relative to that of CuO. These shifts indicate that the Cu3+ is in an octahedral site linked to neighboring Cu3+ via a single 180CuOCu bridge in a metallic phase. This spectrum is, therefore, can be used as a useful standard for comparison with the XPS spectra of the p-type high-Tc copper oxides.

An Investigation of the Equation of State of NaCl at High Pressure by Use of Gordon-Kim Model

WU Shao-Zeng, ZHANG Cheng-Xiang, WU Shu-Yan, WANG Rong, ZHU Hai-Jun

1992, 6(1): 15-22 . doi: 10.11858/gywlxb.1992.01.003

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Abstract:
Pair-potentials of ions in the NaCl crystal are calculated by using Gordon-Kim model and numerical solutions of Hartree-Fock wave functions for free ions. Results show that short range interactions have different properties for different pairs of ions, the cation-anion pair interaction potential is repulsive, but the cation-cation and anion-anion pair interaction potentials are attractive in the separation range of interest here. Different functional forms of these potentials are adopted and the parameters are determined by the least-square-fit. The Gruneisen parameter and the equation of state of NaCl are calculated by using the theory of lattice dynamics. Agreements between the calculated results and the experimental data are satisfactory.

Interference Diagnosis of Laser Induced Vapor Plume

YUAN Yong-Hua, LIU Chang-Ling, GUI Yuan-Zhen, ZHANG Ning

1992, 6(1): 23-29 . doi: 10.11858/gywlxb.1992.01.004

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Abstract:
Characterizations of the vapor plume from LY12 aluminum target irradiated by a focused normal mode pulsed Nd: glass laser beam have been studied by using of a plate shearing interferometer and the high speed photography. The frame photos show that the speed of shock wave in the air is bout 473 m/s, the vapor plume front is about 162 m/s. By using the Abel inversion and Saha equations to analyze the interferogram of the vapor plume, based on electron density is deduced to be about 3.11017 cm-1, the temperature about 6 096 K, iconicity about 0.014, and optic absorption about 0.03 cm-1.

Study on Vibration Spectra of cBN Synthesized under High Pressure and High Temperature

ZHANG Tie-Chen, YANG Jun, ZHAO Yong-Nian, ZOU Guang-Tian, CUI Qi-Liang

1992, 6(1): 30-36 . doi: 10.11858/gywlxb.1992.01.005

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Abstract:
Phonon absorption and reflection of the lattice vibration of different color cBN synthesized by static high-pressure high-temperature method were investigated, much information about its lattice vibrations being obtained. Three new spectrum lines of lattice vibration in the range from 1 000 cm-1 to 1 300 cm-1 were observed, one of which is ascribed to the TO mode couple of body-surface phonons, the other two lines may probably be caused by the absorption of impurities.

Research on Thermodynamic Mechanism of Diamond Surface Metallization

SUN Yu-Chao

1992, 6(1): 37-47 . doi: 10.11858/gywlxb.1992.01.006

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Abstract:
The wetting of diamond by three kinds of liquid alloy and its surface metallization by means of solid contact techniques were systematically studied. The micro structure of the surface-metallized diamond in the matrix alloy as well as its chemical compositions distribution were investigated by SEM analyses X-ray diffraction, were used to observe the phase structure of the carbides formed on the diamond surface. Also, the thermodynamic mechanism for the formation of the carbides was preliminarily discussed.

The Compression Behavior of Raman Active Mode E2g of Graphite and the Pressure Effect of Force Constant of CC Bonding

ZHAO Yong-Nian, ZHANG Zhi-Lin, CUI Qi-Liang, LIU Zhen-Xian, ZOU Guang-Tian

1992, 6(1): 48-53 . doi: 10.11858/gywlxb.1992.01.007

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Abstract:
The frequency changes of Raman active mode E2g of graphite were measured with pressure in the range of 0 to 13 GPa. The results show that a discontinuity in d/dp appeared near 4 GPa and that d/dp is larger before the discontinuous point than behind it. This may be caused by the distortion of the hexagonal network of graphite near 4 GPa. In this paper, we also obtained a relation about the force constant of CC bonding of graphite under high pressure and revised E. Fitzer's equation on calculating the length of CC bonding with Raman frequency at ambient pressure.

The Dependence of Constitutive Model on the Density, Temperature, Pressure and Strain Rate

LI Mao-Sheng, WANG Zheng-Yan, CHEN Dong-Quan, WANG Xiao-Sha

1992, 6(1): 54-57 . doi: 10.11858/gywlxb.1992.01.008

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Abstract:
We introduce strain rate into constitutive model and integrate dynamic and static yield into the same model. Results of computation for 2024Al are in good agreement with experiments.

Study on the Spallation Behavior of Tungsten Alloy

ZENG Yuan-Jin, JING Fu-Qian, ZHANG Wan-Jia

1992, 6(1): 58-67 . doi: 10.11858/gywlxb.1992.01.009

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Abstract:
Spallation behavior of a kind of tungsten alloy, with composition percent by weight W90%-Ni6.8%-Fe2.7%-Cr0.5% and manufactured by powder metallurgical method, was investigated by using a compressed gas gun as impact loading device. The peak stress in target is 5~10 GPa, stress duration 0.2~0.6 s. The stress history measured by manganin gauge embedded in target/window interface demonstrated that the spallation strength of the tungsten alloy is a monotonic increasing function of square root of tensile stress rate and independent on the peak stress level. Metallographic analysis for the recovery sample showed that the tensile fracture of the tungsten alloy occurs mainly in the Fe-Ni mixture region with a few transcrystalline fracture in tungsten grain and there exhibits many cup-like pits on the fractographic surface as well. It can be seen from those mentioned above that the tensile fracture of the tungsten alloy is essentially contributed to the ductile fracture mechanism.

A Plating Manganin Piezoresistance Gauge

SHI Shang-Chun, ZHANG Qing-Fu, LUO Jiao-Ming, CHENG Ju-Xin, CHEN Pan-Sen

1992, 6(1): 68-74 . doi: 10.11858/gywlxb.1992.01.010

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Abstract:
The magnetically controlled cathode plasma sputtering technique has been successfully used to manufacture a plating-type manganin piezoresistance gauge on a mica matrix plate. Calibration experiments under pressures 5 to 6 GPa show that the piezoresistance behavior is well-reproduceable. The pressure-piezoresistance fit of the gauge can be written as p(GPa)=-0.14+90.63(R/R0)+10.81(R/R0)2-7.64(R/R0)3, here, R0 is the initial resistance of the gauges, R the resistance increment under shock loading.

Phase Decomposition of FexN Compounds under High Pressures

WEI Yu-Nian, SUN Ke, FENG Yuan-Bing, YAO Yu-Shu, LIU Shi-Chao, WANG Wen-Kui

1992, 6(1): 75-80 . doi: 10.11858/gywlxb.1992.01.011

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Abstract:
The effect of pressure on the decomposition of compounds FexN at room temperature has been investigated X-ray diffraction analysis shows that high pressure prompts nitrogen atoms precipitating from the lattice of FexN compounds, causing phase decomposition and forming parent phase and -Fe. This phenomenon increases with increasing pressure. Dynamic process of nitrogen precipitation and the activation volume in FexN have been investigated by analyzing the relative content of -Fe in the parent phase FexN. The activation volume of Fe3N and Fe4N are 2.2410-5 m3/mol and 1.6210-5 m3/mol, respectively. The Fe16N2 compound can be obtained at appropriate condition by annealing the FexN compounds which have been compacted under high pressure.

1992 Vol. 6, No. 1

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