scholarly journals Phase Diagram of The Ternary BaO-Bi2O3-B2O3 System: New Compounds and Glass Ceramics Characterisation

10.5772/52405 ◽  
2012 ◽  
Author(s):  
Martun Hovhannisyan
Keyword(s):  
Phase Diagram ◽  
Glass Ceramics ◽  
New Compounds

The silver–calcium phase diagram

1969 ◽  
Vol 47 (4) ◽  
pp. 611-614 ◽  
Author(s):  
W. A. Alexander ◽  
L. D. Calvert ◽  
A. Desaulniers ◽  
H. S. Dunsmore ◽  
D. F. Sargent
Keyword(s):  
Thermal Analysis ◽  
Phase Diagram ◽  
Composition Range ◽  
Liquidus Curve ◽  
X Ray Diffraction ◽  
X Ray ◽  
Novel Technique ◽  
New Compounds ◽  
First Time ◽  
Made In

The silver–calcium system has been reinvestigated over the whole composition range by thermal analysis, X-ray diffraction, and metallography. A novel technique has been used to prepare and examine these reactive alloys. In the course of this project four intermetallic compounds have been observed for the first time; while two others, viz., Ag2Ca and AgCa, which were reported before by others, have been confirmed. Three of the new compounds are: Ag8Ca3, Ag3Ca5, and AgCa3, while the fourth was not isolated or examined in detail. Two other compounds which were described in earlier work as Ag4Ca and Ag3Ca, have been found to be Ag9Ca2 and Ag7Ca2, respectively. Major modifications have been made in the liquidus curve and possible reactions in the solid state are indicated.

scholarly journals The Y–Mg–Co ternary system: alloys synthesis, phase diagram at 500 °C and crystal structure of the new compounds

2020 ◽  
Vol 812 ◽  
pp. 152072 ◽  
Author(s):  
V.V. Shtender ◽  
V.V. Pavlyuk ◽  
O.Ya Zelinska ◽  
W. Nitek ◽  
V. Paul-Boncour ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Diagram ◽  
Ternary System ◽  
New Compounds

scholarly journals Unusual crystal structures in the system (SnSe)nBi2Se3

2014 ◽  
Vol 70 (a1) ◽  
pp. C1117-C1117
Author(s):  
Philipp Urban ◽  
Christina Fraunhofer ◽  
Felix Fahrnbauer ◽  
Gerald Wagner ◽  
Oliver Oeckler
Keyword(s):  
Thermal Conductivity ◽  
Phase Diagram ◽  
Room Temperature ◽  
Structure Type ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
New Compounds ◽  
New Phase ◽  
Huge Variety ◽  
Stacking Disorder

As intermediates between layered tellurides and chain-like sulfides, selenides exhibit a huge variety of structures and are promising candidates for thermoelectrics. The compounds (SnSe)nBi2Se3 cover the whole range of compound classes. (SnSe)0.5Bi2Se3 exhibits the 21R-GeSb2Te4 structure type (R-3m, a = 4.172Å, c = 38.86 Å, R1(obs) = 0.0246) [1] instead of the 12P stacking expected for this stoichiometry, HRTEM indicates the presence of stacking disorder. This phase coexists with "phase X" [2]. From such samples, e.g. (SnSe)~2Bi2Se3, single crystals of new compounds could be retrieved. Their structures resemble those of minerals of the lillianite series. Slowly cooled samples near the dystectic composition [2] in the phase diagram yielded lillianite-type (SnxBi1-x)5Se6 (x ≍ 2, Cmcm, a = 4.196 Å, b = 13.83 Å, c = 21.19 Å, R1(obs) = 0.0347) mixed with (SnxBi1-x)11Se13 (x ≍ 3, C2/m, a = 13.85 Å, b = 4.205 Å, c = 23.33 Å, β = 98.70, R1(obs) = 0.0594), which is isotypic to KSn5Bi5Se13 [3]. Further a new phase (SnxBi1-x)8Se9 with heyrovskite-type structure (x ≍ 3, Cmcm, a = 4.193 Å, b = 13.87Å, c = 32.01 Å, R1(obs) = 0.0392) was obtained. These new structures consist of tropochemically twinned slabs that represent distorted cutouts of the rocksalt type. They are interconnected via cations in trigonal prisms. They are members of a homologous series that differ concerning the thickness of the slabs. The cubic high-temperature phase (SnSe)nBi2Se3 (~2.5 < n < 4) yields a metastable pseudocubic disordered rocksalt-type material (Fm-3m, a = 5.936 Å, R1(obs) = 0.0473) upon quenching. For n = 4, it contains homogeneously distributed nanoscale SnSe precipitates. Such a heterostructure might explain the low thermal conductivity (0.83 Wm-1K-1 at room temperature). The rather low electrical conductivity might be further tuned by substitution, which promises an intriguing approach for new nanostructured thermoelectrics easily accessible by partial phase transitions and exsolution effects.

OS0108 Production of Glass and Glass-Ceramics from Industrial Wastes Using Phase Diagram of CaO-Al_2O_3-SiO_2 System

2011 ◽  
Vol 2011 (0) ◽  
pp. _OS0108-1_-_OS0108-2_
Author(s):  
Kiyohiko IKEDA ◽  
Takehisa TOKUMARU ◽  
Hiroyuki KINOSHITA ◽  
Ryuusuke KAWAMURA ◽  
Akira YOSHIKAWA ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Glass Ceramics ◽  
Industrial Wastes

Zum System Bi2O3 /Bi2Se3/BiCl3,I. Das Zustandsdiagramm Bi2O3/Bi2Se3/BiCl3/On the System Bi2O3/Bi2Se3/BiCl3, I. The Phase Diagram Bi2O3/Bi2Se3/BiCl3

2000 ◽  
Vol 55 (7) ◽  
pp. 603-613 ◽  
Author(s):  
P. Schmidt ◽  
H. Oppermann
Keyword(s):  
Phase Diagram ◽  
Chemical Vapour ◽  
Phase Relations ◽  
Vapour Transport ◽  
Chemical Equilibria ◽  
X Ray ◽  
Chemical Vapour Transport ◽  
Heterogeneous Chemical ◽  
Quaternary Compounds ◽  
New Compounds

Abstract The phase relations in the quaternary system Bi/Se/O/Cl have been studied and the existence of several new compounds in the pseudotemary area Bi2O3/Bi2Se3/BiCl3 has been established by solid state and chemical vapour transport reactions. The phase diagram is derived from X-ray powder diffraction and thermal analysisdata, and from measurements of the decomposition pressure behaviour. Three new quaternary phases with different compositions exist in the system: Bi4O4SeCl2, Bi10O12SeCl4 and Bi22O28SeCl8.By estimation of the thermodynamic data of the quaternary phases it is possible to calculate complex heterogeneous chemical equilibria between all the binary, ternary and quaternary compounds of the phase diagram. As a result, we can describe thermodynamically the observed phase relations and the direction of thermal decomposition of the respective compounds.

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

Crystal chemistry of high-Tc superconductors

1990 ◽  
Vol 48 (4) ◽  
pp. 1118-1119
Author(s):  
Maryvonne Hervieu
Keyword(s):  
Oxygen Deficiency ◽  
Large Family ◽  
Copper Oxides ◽  
High Tc Superconductors ◽  
High Tc ◽  
Single Mechanism ◽  
Square Planar ◽  
History Of ◽  
Bismuth Cuprates ◽  
New Compounds

Four years after the discovery of superconductivity at high temperature in the Ba-La-Cu-O system, more than thirty new compounds have been synthesized, which can be classified in six series of copper oxides: La2CuO4 - type oxides, bismuth cuprates, YBa2Cu3O7 family, thallium cuprates, lead cuprates and Nd2CuO4 - type oxides. Despite their quite different specific natures, close relationships allow their structures to be simply described through a single mechanism. The fifth first families can indeed be described as intergrowths of multiple oxygen deficient perovskite slabs with multiple rock salt-type slabs, according to the representation [ACuO3-x]m [AO]n.The n and m values are integer in the parent structures, n varying from 0 to 3 and m from 1 to 4; every member of this large family can thus be symbolized by [m,n]. The oxygen deficient character of the perovskite slabs involves the existence or the co-existence of several types of copper environment: octahedral, pyramidal and square planar.Both mechanisms, oxygen deficiency and intergrowth, are well known to give rise easily to nonstoichiometry phenomena. Numerous and various phenomena have actually been characterized in these cuprates, strongly depending on the thermal history of the samples.

Evaluation of New Compounds for Opioid Activity: Annual Report (1993)

1994 ◽  
Author(s):  
J. C. Woods ◽  
◽  
C. P. France ◽  
F. Medzihradsky ◽  
C. B. Smith ◽  
...  
Keyword(s):  
Annual Report ◽  
Opioid Activity ◽  
New Compounds
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