Crystals of magnetite (Fe(3)O(4)) and periclase (MgO) in Fe-Mg-Ca carbonate in the Martian meteorite Allan Hills 84001 were studied by using transmission electron microscopy to understand their origin and evaluate claims that the magnetites were made by Martian microorganisms. In magnesian carbonate, periclase occurs as aggregates of crystals (grain size approximately equal to 3 nm) that are pr...

In contrast to most ionic minerals studied by SFM, the periclase (001) surface dissolves not by retreat of monolayer steps parallel to (001), but by retreat of a rough surface perpendicular to (001). At pH , 2, dissolution has an additional contribution from retreating macro-steps at the edges of nearly square pits. The macro-steps have heights up to 120 nm. In general, step direction is parall...

Thermochemical and compressibility data are used to calculate the approximate pressures and temperatures required for the reaction of clinoenstatite to Mg•SiO• (spinel or olivine) or to periclase and stishovite, the reaction of forsteritc to Mg•SiO• (spinel) or periclase and stishovite, and the breakdown of Mg•SiO• (spinel) to periclase and stishovite. The calculated reaction lines for Mg•SiO• ...

In this paper, the processes of decarburization periclase-carbon and aluminum-periclase-carbon ladle refractories were investigated. Decarburization take place already at stage drying heating lining after repair, during its heat treatment on gas or electric stands. These cause irreparable damage to even before is put into direct operation (before contact with molten steel). One ways increase re...

We have used first principles methods to calculate the partitioning of water between perovskite and ringwoodite under lower mantle and Fe-free conditions. We find that incorporation of water into ringwoodite is more favourable than into perovskite by about 0.25 eV per formula unit, or about 24 kJ/mol. This translates to a ringwoodite to perovskite partition coefficient of between 10 and 13, dep...

Over the past decades, development and improvement of refractory materials for lining high-temperature zones rotary kilns continues. The main requirements products cement clinker roasting are: high density ultimate compressive strength, low porosity gas permeability, increased abrasion resistance, thermal conductivity, corrosion resistance ability to form a protective layer.Today, goal modern r...

To study the viscosity of bridgmanite and ferropericlase aggregate, uniaxial compression deformation experiments on pre-synthesized post-spinel phase two-layered samples were conducted under top lower mantle pressure 1773 K utilizing DT-Cup apparatus. Up to strain 0.25 ± 0.05, observed comparable suggests dominates bulk without localization in periclase. The microstructures deformed show eviden...