Thermodynamics and Phase Stability in the Si—O System

Abstract

For Abstract see ChemInform Abstract in Full Text.

A computational analysis of a ZrO2–SiO2 scale for a ZrB2–ZrC–Zr ultrahigh temperature ceramic composite system

“…At temperatures greater than 1687 • C, liquid silica would equilibrate with the ZrO 2 phase as expected from the phase diagram. In addition, with impurities collecting in the grain boundaries, the SiO 2 phase would probably melt below its melting point of 1723 • C, which is usually reported for phase diagrams containing silica, 14 or the recent calculated melting temperature of 1725 • C according to Schnurre et al 15 The flexural strength of SiO 2 steadily increases from 70 MPa at 300 K to 95 MPa at 2000 K according to Borodai. 16 The flexural strength and elastic modulus of ZrO 2 -6.5 mol% Y 2 O 3 , as reported by Adams et al 17 was reviewed to determine the possible deformation mechanisms of a ZrO 2 layer of the scale.…”

Oxygen distribution on a multicrystalline silicon ingot grown from upgraded metallurgical silicon

“…This is, in turn, due to the production process and long holding time of the feedstock at high temperatures ( 41550 1C). At 1550 1C the solubility of oxygen in silicon is approximately 122 ppma [16]. Moreover, the large difference (5-10 ppma) between total and interstitial oxygen concentration led to assume that a large amount of precipitates was present in the material.…”

Effect of SiO2 Dispersion on Chlorine-Induced High-Temperature Corrosion of High-Velocity Air-Fuel Sprayed NiCrMo Coating

“…Although such crystalline forms attain different physical characteristics due to their internal structures (owing to different arrangements of Si and O layers), the chemical composition is identical (each Si is always surrounded by four O atoms). Moreover, as these crystalline forms of SiO2 are stable in the high temperature corrosion test condition of the present study (600 °C) [39], these three phases were similarly considered as SiO2. The effect of each SiO2 crystalline phase on the high temperature corrosion behavior of the coatings is not under the scope of the present study, but a research subject for further investigation in future.…”