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Boron is an element of fascinating chemical complexity. Controversies have shrouded this element since its discovery was announced in 1808: the new 'element' turned out to be a compound containing less than 60-70% of boron, and it was not until 1909 that 99% pure boron was obtained. And although we now know of at least 16 polymorphs, the stable phase of(More)
In situ x-ray diffraction study of the hexagonal 6H SiC under pressure and shear in rotational diamond anvil cell is performed that reveals phase transformation to the new high-density amorphous (hda) phase SiC. In contrast to known low-density amorphous SiC, hda-SiC is promoted by pressure and unstable under pressure release. The critical combination of(More)
The effect of shear strain on the iron α-ε phase transformation has been studied using a rotational diamond anvil cell (RDAC). The initial transition is observed to take place at the reduced pressure of 10.8 GPa under pressure and shear operation. Complete phase transformation was observed at 15.4 GPa. The rotation of an anvil causes limited pressure(More)
Disordered structures of boron nitride (BN), graphite, boron carbide (BC), and boron carbon nitride (BCN) systems are considered important precursor materials for synthesis of superhard phases in these systems. However, phase transformation of such materials can be achieved only at extreme pressure-temperature conditions, which is irrelevant to industrial(More)
Plastic shear significantly reduces the phase transformation (PT) pressure when compared to hydrostatic conditions. Here, a paradoxical result was obtained: PT of graphitelike hexagonal boron nitride (hBN) to superhard wurtzitic boron nitride under pressure and shear started at about the same pressure ( approximately 10 GPa) as under hydrostatic conditions.(More)
A high pressure angle dispersive synchrotron x-ray diffraction study of titanium disulfide (TiS(2)) was carried out to pressures of 45.5 GPa in a diamond-anvil cell. We observed a phase transformation of TiS(2) beginning at about 20.7 GPa. The structure of the high pressure phase needs further identification. By fitting the pressure-volume data to the(More)
We report on an original method that measures sample thickness in a diamond anvil cell under high pressures. The method is based on two hypotheses: completely plastic deformation on the gasket and completely elastic deformation of the diamonds. This method can further eliminate the effect of diamond deformation on the thickness measurement of a sample,(More)
Two-electrode configuration was developed for in situ electrical impedance detecting on diamond anvil cell under high pressure. The metal gasket was used as one electrode and the risk coming from electrical short between sample and interside wall of the gasket was eliminated. The configuration was evaluated and proved to be effective by measuring the(More)
A method for in situ Hall effect measurement under high pressure was developed on a diamond anvil cell. The electrode was accurately integrated on one diamond anvil with regular shape. A uniform and strong magnetic field was introduced into the sample zone. The voltage errors brought by some negative effects during the measurement were well eliminated. The(More)