Pressure dependence of electrical conductivity for fused mercuric halides

1971 ◽  
Vol 67 ◽  
pp. 1115 ◽  
Author(s):  
B. Cleaver ◽  
S. I. Smedley
Keyword(s):  
Electrical Conductivity ◽  
Pressure Dependence ◽  
Mercuric Halides

Dehydration and decomposition of pyrophyllite at high pressures: electrical conductivity and X-ray diffraction studies to 5 GPa

1997 ◽  
Vol 34 (6) ◽  
pp. 875-882 ◽  
Author(s):  
Tara L. Hicks ◽  
Richard A. Secco
Keyword(s):  
Electrical Conductivity ◽  
South African ◽  
Pressure Dependence ◽  
High Pressures ◽  
Ionic Conduction ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Dependence Of Conductivity

The dehydration and decomposition of South African pyrophyllite were studied in the pressure range 2.5–5.0 GPa and in the temperature (T) range 295–1473 K using both in situ electrical conductivity measurements and X-ray diffraction studies on the recovered samples. Activation energies for conduction (Qc) vary in the range 0.02–0.07 eV for T ≤ 500 K where the dominant conduction mode is electronic, and Qc is in the range 1.10–1.28 eV for T ≥ 500 K where ionic conduction dominates. Abrupt changes in the isobaric temperature dependence of conductivity mark the onset of dehydration and subsequent decomposition into kyanite plus quartz–coesite. At 2.5 GPa, South African pyrophyllite forms the dehydroxylate phase at 760 K with a pressure dependence of ~30 K/GPa and complete decomposition follows at 1080 K with a pressure dependence of ~41 K/GPa. The resulting pressure–temperature phase diagram is in very good agreement with many previous studies at 1 atm (101.325 kPa).

scholarly journals Fast Diffusion of Iron in Single Crystal Rutile and Iron Doped Rutile

1983 ◽  
Vol 24 ◽  
Author(s):  
J. Sasaki ◽  
N. L. Peterson ◽  
L. C. De Jonghe
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Pressure Dependence ◽  
Ionic Conduction ◽  
Complex Impedance ◽  
Fast Diffusion ◽  
Iron Ions ◽  
Impedance Measurements ◽  
Fe Content ◽  
Shear Structure

ABSTRACTTracer diffusion coefficients of Fe, DFe* in single crystals of rutile and of 0 –2.0% Fe doped rutile were measured. The oxygen pressure dependence of DFe* in pure rutile showed complicated behavior. The values of DFe* may consist of contributions from Fe2+ ions diffusing by an interstitial mechanism and from Fe3+ ions diffusing by an interstitialcy mechanism in cooperation with tetravalent titanium interstitial ions, Tii. The value of DFe* in Fe doped rutile attains a saturation value when the Fe content reaches about 0.1%, D*Fe decreases drastically when the Fe content exceeds about 0.35%. Complex impedance measurements of electrical conductivity indicate the existence of ionic conduction for Fe doped rutile containing less than 0.35% of Fe. The small ionic conductivity relative to the values of D*Fe suggests that only a small fraction of the iron ions are highly mobile. Above 0.35% Fe, the observed drastic decrease in D*Fe may result from the formation of a shear structure In highly doped rutile.

Temperature and pressure dependence of electrical conductivity in synthetic anorthite

2015 ◽  
Vol 276 ◽  
pp. 136-141 ◽  
Author(s):  
Haiying Hu ◽  
Lidong Dai ◽  
Heping Li ◽  
Keshi Hui ◽  
Jia Li
Keyword(s):  
Electrical Conductivity ◽  
Pressure Dependence ◽  
Temperature And Pressure

Temperature and Pressure Dependence of the Electrical Conductivity of Two Tetraalkylammonium Tetraalkylborate Salts

1999 ◽  
Vol 52 (5) ◽  
pp. 373 ◽  
Author(s):  
Nashiour Rohman ◽  
Sekh Mahiuddin ◽  
Raymond Aich ◽  
Klaus Tödheide
Keyword(s):  
Electrical Conductivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Pressure Dependence ◽  
Empirical Equation ◽  
Electrical Conductivities ◽  
Temperature And Pressure ◽  
Isothermal Equation ◽  
Key Parameter ◽  
The Ideal

Electrical conductivities of molten trimethylpentylammonium triethyloctylborate (N1115B2228) and triethylpentylammonium triethylpentylborate (N2225B2225) were measured as functions of temperature (c. 293 · 15–383 · 15 K) and pressure (from 1 bar to 5 kbar). Analysis of the temperature dependence of the electrical conductivity was made by using the Vogel–Tammann–Fulcher equation, κ = Aexp[ – B/(T – T0)]. The empirical nature of the pressure dependence of the B and T0 parameters has revealed the possibility of obtaining an isothermal equation to explain the pressure dependence of the electrical conductivity. Accordingly, an empirical equation of the form κ = a′exp(b′ P+c′ P2) has been found to describe the pressure dependence of the electrical conductivity. The ideal glass transition temperature, T0, is the key parameter in controlling the pressure dependence of the electrical conductivity for both systems under study.

Sign in / Sign up

Export Citation Format

Share Document