12013-56-8Relevant articles and documents
Thermodynamic stabilities of intermediate phases in the Ca-Si system
Brutti,Ciccioli,Balducci,Gigli,Manfrinetti,Napoletano
, p. 525 - 531 (2001)
Vaporization thermodynamics in the binary system calcium-silicon has been studied by Knudsen effusion-mass spectrometry and vacuum microbalance techniques. The equilibrium partial pressure of Ca(g) over the two-phase regions in the composition range 20-75
Dumbbells of five-connected silicon atoms and superconductivity in the binary silicides MSi3 (M = Ca, Y, Lu)
Schwarz, Ulrich,Wosylus, Aron,Rosner, Helge,Schnelle, Walter,Ormeci, Alim,Meier, Katrin,Baranov, Alexey,Nicklas, Michael,Leipe, Susann,Mueller, Carola J.,Grin, Yuri
, p. 13558 - 13561 (2012)
The new metastable binary silicides MSi3 (M = Ca, Y, Lu) have been synthesized by high-pressure, high-temperature reactions at pressures between 12(2) and 15(2) GPa and temperatures from 900(100) to 1400(150) K. The atomic patterns comprise int
Evers, Juergen,Oehlinger, Gilbert,Weiss, Armin
, p. 399 - 402 (1980)
Phase selection during calcium silicide formation for layered and powder growth
Wen, Cuilian,Kato, Akihiko,Nonomura, Tomomi,Tatsuoka, Hirokazu
, p. 4583 - 4587 (2011)
Phase selection during Ca silicide formation was discussed using the chemical potential and the effective heat of formation (ΔH′) models. The compositional analyses of Ca silicides were experimentally carried out in detail for both the layered and powder
High pressure synthesis and crystal structure of a ternary superconductor Ca2Al3Si4 containing layer structured calcium sub-network isomorphous with black phosphorus
Tanaka, Masashi,Zhang, Shuai,Tanaka, Yuki,Inumaru, Kei,Yamanaka, Shoji
, p. 445 - 451 (2013)
The Zintl compound CaAl2Si2 is peritectically decomposed to a mixture of Ca2Al3Si4 and aluminum metal at temperatures above 600 °C under a pressure of 5 GPa. The new ternary compound Ca2Al3Sl4 crystalizes with the space group Cmc21 and the lattice parameters a=5.8846(8), b=14.973(1), and c=7.7966(5) A. The structure is composed of aluminum silicide framework [Al3Si4] and layer structured [Ca 2] network interpenetrating with each other. The electron probe microanalysis (EPMA) shows the formation of solid solutions Ca 2Al3-xSi4+x (x2] sub-network is isomorphous with black phosphorus. The new ternary compound shows superconductivity with a transition temperature (T c) of 6.4 K. The band structure calculation suggests that the superconductivity should occur through the conduction bands mainly composed of 3p orbitals of the aluminum silicide framework.
Heat capacity and thermodynamic properties of some Ca silicides
Canepa,Napoletano,Manfrinetti,Palenzona
, p. 20 - 23 (2000)
The heat capacities of three Ca compounds, namely CaSi2, Ca3Si4 and Ca14Si19 were measured in the 3-300 K temperature range by adiabatic calorimetry. No thermal anomalies were found in the whole temperature range. In the three Ca silicides, from an analysis of the low temperature data (Ta power law lower than three in the lattice heat capacity behaviour was observed and tentatively ascribed to the layered structure of the compounds, in agreement with structural informations. From heat capacity data the thermodynamic functions entropy, enthalpy and Gibbs energy were calculated at 298 K.
Effect of electrolysis potential on reduction of solid silicon dioxide in molten CaCl2
Yasuda, Kouji,Nohira, Toshiyuki,Ito, Yasuhiko
, p. 443 - 447 (2005)
Electrochemical reduction of solid SiO2 by using a contacting electrode method was investigated in molten CaCl2 at 1123 K. The samples were prepared by potentiostatic electrolysis at 0.35-1.30 V (vs. Ca 2+/Ca) for 1 h. From the results of XRD, SEM and EPMA, it was confirmed that SiO2 was electrochemically reduced to Si at 1.25 V or more negative potential, which agreed with the thermodynamic calculation. The current-time curves during electrolysis and the cross-sectional SEM measurements of the samples clearly showed that reduction rate is higher at more negative potential. In addition, Si-Ca alloy formation was confirmed at 0.35 V.
