Surface structure and energetics of low index facets of bismuth ferrite

2020 ◽  
Vol 22 (28) ◽  
pp. 16400-16406
Author(s):  
Dennis Trujillo ◽  
Ayana Ghosh ◽  
Serge M. Nakhmanson ◽  
Sanjubala Sahoo ◽  
S. Pamir Alpay
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Surface Structure ◽  
Electronic Properties ◽  
Thermodynamic Stability ◽  
Bismuth Ferrite ◽  
Chemical Potentials ◽  
Stability Structure

Thermodynamic stability, structure and electronic properties of BiFeO3 surfaces depend on oxygen partial pressure and chemical potentials of bismuth and iron.

scholarly journals System Bi–Sr–O: Synergistic measurements of thermodynamic properties using oxide and fluoride solid electrolytes

1998 ◽  
Vol 13 (7) ◽  
pp. 1905-1918 ◽  
Author(s):  
K. T. Jacob ◽  
K. P. Jayadevan
Keyword(s):  
Phase Diagram ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Chemical Potential ◽  
Free Energies ◽  
Two Phase ◽  
Chemical Potentials ◽  
Phase Fields ◽  
The Stability ◽  
Ternary Oxides

Phase equilibrium and electrochemical studies of the ternary system Bi–Sr–O indicate the presence of six ternary oxides (Bi2SrO4, Bi2Sr2O5, Bi2Sr3O6, Bi4Sr6O15, Bi14Sr24O52, and Bi2Sr6O11) and three solid solutions (δ, β, and γ). An isothermal section of the phase diagram is established at 1050 K by phase analysis of quenched samples. Three compounds, Bi4Sr6O15, Bi14Sr24O52, and Bi2Sr6O11, contain Bi5+ ions. The stability of these phases is a function of oxygen partial pressure. The chemical potentials of SrO in two-phase fields are determined as a function of temperature using solid-state cells based on single crystal SrF2 as the electrolyte. Measurement of the emf of cells based on SrF2 as a function of oxygen partial pressure in the gas at constant temperature gives information on oxygen content of the compounds present at the electrodes. The chemical potentials of Bi2O3 in two-phase fields of the pseudobinary Bi2O3–SrO are measured using cells incorporating (Y2O3)ZrO2 as the solid electrolyte. The standard free energies of formation of the ternary oxides are calculated independently using emfs of different cells. The independent assessments agree closely; the maximum difference in the value of of component binary oxides. The results are discussed in the light of the phase diagram and compared with calorimetric and chemical potential measurements reported in the literature. The combined use of emf data from cells incorporating fluoride and oxide electrolytes enhances the reliability of derived data.

scholarly journals Effect of Hot-Dip Galvanizing Process on Selective Oxidation and Galvanizability of Medium Manganese Steel for Automotive Application

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1265
Author(s):  
Zhang Chen ◽  
Yanlin He ◽  
Weisen Zheng ◽  
Hua Wang ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Surface Oxidation ◽  
Steel Sample ◽  
Dew Point ◽  
Manganese Steel ◽  
Automotive Application ◽  
Stable Phase ◽  
Annealing Atmosphere ◽  
Medium Manganese Steel

A medium manganese steel with 7.5 wt.% Mn for automobile application was galvanized in a continuous Hot Dip Galvanizing (HDG) simulator under different galvanizing conditions. It was shown that the effects of dew point, annealing temperature and annealing atmosphere on the surface oxidation of steel could be comprehensively evaluated by the consideration of oxygen partial pressure P(O2). Although Mn2SiO4 was a thermodynamic stable phase when P(O2) varied from 10−28 to 10−21 atm, it was difficult to form Mn–Si–O composite oxide because there was no enrichment of silicon on the steel surface. So, this oxide was generally formed in the Fe substrate and had little effect on the galvanizability. With the increase in P(O2) above 10−25 atm, MnO particles in the form of the thermodynamic stable phase became coarser and tended to aggregate, which hindered the formation of a continuous inhibition layer, resulting in the defects of bare spots on the galvanized surface of the steel. When the oxygen partial pressure greater than 10−22 atm, film-like MnO layer was formed on the surface of steel sample, which obviously deteriorated the galvanizability. The galvanizability of the steel can be improved by the regulation of oxygen partial pressure; based on this, the reasonable zinc plating process parameters can be developed.

Quantitative evaluation of the oxidation behavior of ZrB2-15 vol.%SiC at a low oxygen partial pressure

Vacuum ◽  
2013 ◽  
Vol 88 ◽  
pp. 98-102 ◽  
Author(s):  
Ai Momozawa ◽  
Rong Tu ◽  
Takashi Goto ◽  
Yuuki Kubota ◽  
Hiroshi Hatta ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Quantitative Evaluation ◽  
Oxidation Behavior ◽  
Low Oxygen
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