in this experimental work the pressure induced phase transformation of silicon and germaniumhas been studied. it was shown that at a particular value of applied pressure, (pt), depending on the sampletemperature, the electrical resistance of the specimen falls off to a metallic state. the main goal of this studywas to find out how the phase transformation pressure, pt, for a p-type silicon vari...

Phase transformations under high strain rates (dynamic compression) are examined in situ on ZrW2O8, a negative thermal expansion ternary ceramic displaying polymorphism. Amorphization, consistent with prior quasi-static measurements, was observed at peak pressure of 3.0 GPa dynamic conditions, which approximate those expected during fabrication. Evidence partial amorphization lower (1.8 GPa) th...

An in-situ Raman spectroscopic study was conducted to explore the pressure induced phase transformation of spinel-type ferrite ZnFe2O4. Results indicate that ferrite ZnFe2O4 initially transforms to an orthorhombic structure phase (CaFe2O4polymorph) at a pressure of 24.6 GPa. Such a phase transformation is complete at 34.2 GPa, and continuously remains stable to the peak pressure of 61.9 GPa. Th...

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 applications. Here, the phase transitio...

Dielectric relaxation spectra of a metastable crystal phase formed on implosive and exothermic transformation of pressure-amorphized hexagonal ice have been measured in situ at 0.97 GPa pressure over a range of temperature. The metastable phase showed no relaxation peak at 130 K and 0.97 GPa. When heated at a fixed pressure of 0.97 GPa, it began to transform at approximately 145 K exothermally ...