Phase Transformation of Amorphous Boron Nitride under High Pressure

2003 ◽  
Vol 15 (14) ◽  
pp. 2744-2751 ◽  
Author(s):  
Takashi Taniguchi ◽  
Koji Kimoto ◽  
Masataka Tansho ◽  
Shigeo Horiuchi ◽  
Shinobu Yamaoka
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Boron Nitride ◽  
Amorphous Boron

PHASE TRANSFORMATION OF BN NANOPARTICLES UNDER HIGH PRESSURE LOW TEMPERATURE CONDITIONS

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2663-2668 ◽  
Author(s):  
Z. CHEN ◽  
Z. F. LAI ◽  
K. LI ◽  
D. L. CUI ◽  
N. LUN ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Low Temperature ◽  
Boron Nitride ◽  
Hot Pressing ◽  
Cubic Boron Nitride ◽  
Strong Interactions ◽  
Hot Press ◽  
Temperature Conditions ◽  
Pressing Time

Phase transformation of BN nanoparticles under high pressure (580~860MPa) and low temperature (270~325°C) hot press conditions was investigated. It was found that the contents of orthorhombic boron nitride (oBN) and cubic boron nitride (cBN) increased with the increase of temperature and the prolonging of hot pressing time under high pressure conditions. At the same time, because of the intergrowth of hBN, oBN and cBN. there are strong interactions among these three phases.

On the choice of hexagonal boron nitride for high pressure phase transformation using the catalyst solvent process

1991 ◽  
Vol 26 (1) ◽  
pp. 196-202 ◽  
Author(s):  
M. M. Bindal ◽  
B. P. Singh ◽  
S. K. Singhal ◽  
R. K. Nayar ◽  
R. Chopra ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
High Pressure Phase ◽  
Pressure Phase

Synthesis and Decomposition of Ti3SiC2 under 1-5GPa at 1400°C

2014 ◽  
Vol 602-603 ◽  
pp. 499-502 ◽  
Author(s):  
Yuan Yuan Zhu ◽  
Shang Sheng Li ◽  
Liang Li ◽  
Ai Guo Zhou
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Pressure ◽  
Phase Transformation ◽  
Boron Nitride ◽  
Cubic Boron Nitride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ternary Carbide ◽  
Scanning Electron

Ternary carbide Ti3SiC2 is a good binder to make superhard composites with diamonds or cubic boron nitride. Superhard composites are normally made at high temperature and under high pressure around 5 GPa to avoid the phase transformation of diamonds or cubic boron nitride. This paper researched the synthesis of Ti3SiC2 from the powders of Ti, Si, and graphite by a cubic presser under 1 GPa to 4 GPa at 1400°C. The decomposition of Ti3SiC2 under 5GPa at 1400°C was also researched. From X-ray diffraction (XRD) and scanning electron microscopy (SEM) results, Ti3SiC2 was synthesized in 30 min under 1 GPa at 1400°C. The impurities were TiSi2, Ti5Si3Cx, and TiC. As the pressure increased from 1GPa to 4GPa, less Ti3SiC2 more TiSi2 was synthesized. Therefore, high presser > 1GPa is unfavorable for the synthesis of Ti3SiC2. After treated under 5GPa at 1400°C, pure Ti3SiC2 was decomposed.

Effect of pressure on the structure of Fe–N alloys formed by solid-state reaction

2001 ◽  
Vol 16 (9) ◽  
pp. 2583-2590 ◽  
Author(s):  
B. Yao ◽  
L. Liu ◽  
S. E. Liu ◽  
X. Hu ◽  
W. H. Su
Keyword(s):  
High Pressure ◽  
Solid State ◽  
Boron Nitride ◽  
Solid State Reaction ◽  
Atmospheric Pressure ◽  
Amorphous Boron ◽  
Orthorhombic Structure ◽  
Mechanism Of Formation ◽  
Lattice Constants ◽  
Cubic Structure

Fe–N alloys with crystalline structures different from those obtained at atmospheric pressure were produced by solid-state reaction between Fe and amorphous boron nitride under high pressure. Two new paramagnetic Fe–N phases were obtained at temperatures above 800 K under pressures between 2.0 and 4.0 GPa. One is of cubic structure with lattice constant of 6.114 Å, and another is of orthorhombic structure with lattice constants of a = 4 8.443, b = 4 4.749, and c 4 3.993 Å. ε–Fe3Nx with N contents of 18.1 to 21.4 at.%, which could not be obtained at atmospheric pressure, was produced at pressures of 3.0 to 4.0 GPa and temperatures of 690 to 800 K. The mechanism of formation of ε–Fe3Nx under high pressure is discussed.

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