LATTICE PARAMETERS OF MELILITE SOLID SOLUTIONS AND A RECONNAISSANCE OF PHASE RELATIONS IN THE SYSTEM Ca2Al2SiO7 (GEHLENITE) – Ca2MgSi2O7 (AKERMANITE) – NaCaAlSi2O7 (SODA MELILITE) AT 1 000 kg/cm2 WATER VAPOR PRESSURE

1965 ◽  
Vol 2 (6) ◽  
pp. 596-621 ◽  
Author(s):  
A. D. Edgar
Keyword(s):  
Solid Solutions ◽  
Water Vapor Pressure ◽  
Lattice Parameter ◽  
Lattice Parameters ◽  
Phase Relations ◽  
Ray Method ◽  
Subsolidus Phase ◽  
X Ray ◽  
Complete Solid Solution ◽  
Temperature Lattice

The extent of melilite solid solutions has been determined for the systems gehlenite–soda melilite, akermanite–soda melilite, and gehlenite–akermanite–soda melilite at 800 °C and 1 000 kg/cm2[Formula: see text] Approximately 50 weight % NaCaAlSi2O7 will form melilite solid solutions with both gehlenite and akermanite but the extent of complete solid solutions in the gehlenite–akermanite–soda melilite system is very limited at this temperature. Lattice parameter determinations of melilite solid solutions indicate that there is a small but significant change in both a and c parameters with increasing soda melilite in the gehlenite–soda melilite system. In the gehlenite–akermanite–soda melilite system, although the range of complete solid solution is very limited, melilites form more than 90% of the products in most compositions and their lattice parameters can be correlated approximately with their bulk compositions, A rapid X-ray method has been developed to determine the approximate compositions of melilites in this system. Comparison is made between the synthetic samples and natural melilites.A reconnaissance of subsolidus phase relations indicates that phase relations are very complex and that only over a very small compositional range can these systems be considered binary or ternary. These studies also indicate that the relations reported by Nurse and Midgley in 1953 should probably be modified. Although the composition NaCaAlSi2O7 does not synthesize only a melilite under the conditions used in this study, it is believed that this is the correct composition of the sodium-bearing end-member.

SUBSOLIDUS PHASE RELATIONS IN THE SYSTEM Ag–Sb

1966 ◽  
Vol 3 (2) ◽  
pp. 211-222 ◽  
Author(s):  
S. Somanchi
Keyword(s):  
Solid Solutions ◽  
Interplanar Spacing ◽  
Weight Percent ◽  
Phase Relations ◽  
High Angle ◽  
Subsolidus Phase ◽  
X Ray ◽  
Third Phase ◽  
Ε Phase ◽  
Atomic Silver

Phase relations were determined in the Ag–Sb system through the temperature range 500° to 300 °C to permit a better understanding of the origin of certain silver ores and to provide a base for the study of more complex sulfosalt systems. The Sb-rich solvus for the ε phase (Ag6 ± xSb) at 500°, 450°, 350°, and 300 °C occurs at 18.2, 17.75, 17.75, and 17.7 weight percent Sb, respectively. The Ag-rich solvus of the ε′ phase (dyscrasite) occurs at 22.5% Sb at 500 °C and 22.9% at 450°, 400°, 350°, and 300 °C. The Sb-rich solvus of this phase occurs at 27.2% Sb at 500°, 450°, 400°, and 350 °C. Therefore the atomic silver to antimony ratio ranges from nearly 4 to 3, and the formula may be written Ag7 ± xSb2. An order–disorder transition of ε′ to a third phase, ε″, reported to occur at about 440° to 449 °C, was not observed. The compositions of the solid solutions relate to high angle X-ray powder reflections through the following functions: for ε phase, d = 0.000150x + 0.79743, and for ε′ phase, d = 0.00160x + 0.76608, where d is the specific interplanar spacing in Ångstroms and x is the weight percent antimony.

Precision Lattice Parameter Determination at Liquid Helium Temperatures by Double-Scanning Diffractometry

1966 ◽  
Vol 10 ◽  
pp. 354-365 ◽  
Author(s):  
Hubert W. King ◽  
Carolyn M. Preece
Keyword(s):  
Liquid Helium ◽  
Lattice Parameter ◽  
Lattice Parameters ◽  
Parameter Determination ◽  
Double Scanning ◽  
Cryogenic Temperatures ◽  
Included Angle ◽  
X Ray ◽  
Standard Specimens ◽  
Alignment Errors

AbstractThe back-reflect ion double-scanning diffractometer method, by which lattice parameters can be measured with a reproducibility of one part in 150,000 has been applied at liquid helium temperatures. A cryostat attachment is described which enables diffraction profiles to be scanned on both sides of the primary X-ray beam up to 163°, 2θ. Alignment errors may, thus, be eliminated by measuring the included angle 4θ between respective Bragg reflections. The method is illustrated by measuring the lattice parameters of the I.U.Cr. standard specimens of silicon and tungsten at various cryogenic temperatures.

An Approach to the Solid Solution Problem Using a Computerized Identification Technique

1969 ◽  
Vol 13 ◽  
pp. 539-549
Author(s):  
Gerald G. Johnson ◽  
Frank L. Chan
Keyword(s):  
Solid Solution ◽  
Powder Diffraction ◽  
Lattice Parameter ◽  
Powder Diffraction File ◽  
X Ray ◽  
Complete Solid Solution ◽  
Vegard’S Law ◽  
Identification Technique ◽  
Approximate Composition ◽  
End Members

Since for most real systems, solid solution effects influence the position and intensity of the x-ray powder diffraction pattern, it is desirable and necessary to have an automatic system which will identify standard reference phases regardless of the amount of solid solution. Using the system CdS-ZnS, where the lattice parameter a0 changes from 4.136 to 3.820Å, with complete solid solution over the entire range of composition, an illustrative study was made. This work presents the results obtained from a computer analysis of the powder pattern obtained. It has been found that if the starting chemistry is known and the end members of the series are in the ASTM Powder Diffraction File, that the solid solution can be identified. Once the phases present are identified, a plot following Vegard's law yields the approximate composition of the sample under consideration. These two methods of compositional determination agree quite well. Examples of the computer system and description of the program input and output with interpretation of the results will be discussed.

X-ray diffractometry studies and lattice parameter calculation on KNO3–NH4NO3 solid solutions

2005 ◽  
Vol 20 (02) ◽  
pp. 101-104 ◽  
Author(s):  
Wen-Ming Chien ◽  
Dhanesh Chandra ◽  
Jennifer Franklin ◽  
Claudia J. Rawn ◽  
Abdel K. Helmy
Keyword(s):  
Solid Solutions ◽  
Lattice Parameter ◽  
X Ray ◽  
Parameter Calculation

The lattice parameters and interplanar spacings of some artificially prepared melilites

1948 ◽  
Vol 28 (202) ◽  
pp. 374-379 ◽  
Author(s):  
K. W. Andrews
Keyword(s):  
Crystal Structure ◽  
Blast Furnace ◽  
Binary System ◽  
Laboratory Investigation ◽  
Solid Solutions ◽  
Lattice Parameters ◽  
Refractive Indices ◽  
X Ray ◽  
Tetragonal Lattice ◽  
Intermediate Series

A laboratory investigation in connexion with some blast-furnace slags, led to the preparation of the five synthetic melilites for which X-ray data are provided. The five compounds represent gehlenite, åkermanite and three members of the intermediate series of solid solutions, corresponding to 25, 50, and 75 % of åkermanite.The binary system gehlenite–åkermanite was studied by Ferguson and Buddington, who established relationships between refractive indices, density, and composition and determined solidus and liquidus curves. The crystal structure of the melilite group of compounds was investigated by Warren, who showed that the structure was based on a tetragonal lattice.

Derivation of d-Values from Digitized X-ray and Synchrotron Diffraction Data

1989 ◽  
Vol 33 ◽  
pp. 295-303 ◽  
Author(s):  
T. C. Huang ◽  
W. Parrish ◽  
N. Masciocchi ◽  
P. W. Wang
Keyword(s):  
Diffraction Data ◽  
Practical Method ◽  
Xrd Analysis ◽  
Lattice Parameter ◽  
Lattice Parameters ◽  
Synchrotron Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
D Values

AbstractA precise and practical method for the determination of d-values and lattice parameters from digital diffraction data is described. Systematic errors are corrected mathematically during a d-spacing / lattice-parameter least-Squares refincment process making it unnecessary to use internal standards. X-ray and synchrotron diffraction data of an ICDD alumina plate obtained with a wide variety of experimental conditions and analysis parameters were used to study the precision in the derivation of d-values and the accuracy in the determination of lattice parameters. Results showed that the precision in determining d-values was high with |Δd/d|avg ranging from 2x105 to 4x10-5. Using the results obtained from the high precision XRD analysis as a reference standard, the accuracy in the lattice parameter determinations from the synchrotron diffraction data reached the l-2x10-6] range. Lattice parameters, with an accuracy in the high 10-5 range, were also obtained using parameters commonly used in a routine XRD analysis such as a wide RS (0.11°) for high intensity, peaks only in the front reflection region, no Kα2 stripping, and a Single 2θo parameter for systematic error corrections.

Determination of Zinc Sulfide and Cadmium Sulfide in Solid Solutions of Small Single Crystals Used for Semiconductors by X-Ray and Chemical Methods

1961 ◽  
Vol 5 ◽  
pp. 142-152
Author(s):  
Frank L. Chan
Keyword(s):  
Cadmium Sulfide ◽  
Single Crystals ◽  
Zinc Sulfide ◽  
Solid Solutions ◽  
Lattice Parameter ◽  
Chemical Methods ◽  
Pure Zinc ◽  
X Ray ◽  
Mixed Sulfides

AbstractSingle crystals of cadmium sulfide and zinc sulfide have been grown and studied intensively by the Solid State Physics group at the Aeronautical Research Laboratory. The physical phenomena such as reflection, transmission, ultraviolet-excited emission, and electrical resistivity have been observed and characterized on single crystals of these sulfides. Much interest concerning these phenomena has also been centered on single crystals containing both cadmium sulfide and zinc sulfide.For research purposes, mixed crystals as small as a few tenths of 1 mg or less, to 0.5 g of the mixed sulfides, are being prepared. Special chemical methods are required to determine these constituents in them quantitatively. At times, these chemical methods are not applicable, since these methods invariably consume the sample, and, as a result, other observations on the same crystals cannot be performed.Changes in lattice parameter in single crystals of mixed sulfides as compared to pure zinc sulfide or cadmium sulfide provide excellent means for the determination of the percentage of these sulfides. In the X-ray method, single crystals used for the determination of the lattice parameters remain intact. The equipment adopted, procedure used, and the data obtained are illustrated and discussed.In the present study, crystals of cadmium sulfide (greenockite), alpha-zinc sulfide (wurtzite) and solid solutions of these two sulfides having a hexagonal unit cell were used. Since the lattice parameter a0 is found to follow Vegard's law, single-crystal rotation photographs described in this paper were obtained by rotating crystals around the c axis; the lattice parameter was determined with high precision by scanning along the zero-layer line with a microphotometer.

Subsolidus phase relations in the La2O3–Fe2O3–Al2O3 system

2001 ◽  
Vol 16 (3) ◽  
pp. 822-827
Author(s):  
Danjela Kuščer ◽  
Slavko Bernik ◽  
Marko Hrovat ◽  
Janez Holc
Keyword(s):  
Electron Microscopy ◽  
Phase Diagram ◽  
Scanning Electron Microscopy ◽  
Fuel Cell ◽  
Solid Oxide ◽  
Phase Relations ◽  
Oxide Fuel ◽  
Subsolidus Phase ◽  
X Ray ◽  
Scanning Electron

The subsolidus phase relations in the La–Fe–Al–O system were investigated for solid oxide fuel cell (SOFC) applications. Five compounds, LaAlO3, LaAl11O18, LaFe12O19, AlFeO3, and LaFeO3, coexist in the La–Fe–Al–O system at 1380 °C in air. The microstructure and composition of the samples were studied by x-ray diffractometry and scanning electron microscopy. Based on experimental evidence, a phase diagram of the La2O3–Al2O3–Fe2O3 system has been proposed.

Single-Crystal AU-NI Solid Solutions Grown by MBE

1992 ◽  
Vol 280 ◽  
Author(s):  
A. Marty ◽  
B. Gilles ◽  
G. Patrat ◽  
J. C. Joud ◽  
A. Chamberod
Keyword(s):  
Single Crystal ◽  
Solid Solutions ◽  
Room Temperature ◽  
Large Strain ◽  
Grazing Incidence ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
X Ray

ABSTRACTEpitaxial solid solutions Au1-x Nix (100) have been obtained at room temperature on Au(100) substrates by the MBE technique. The layers are 10 nm-thick and the composition x has been varied up to 0.37. A large strain (2–3%) has been measured by X-ray diffraction. The lattice parameters have been measured in two perpendicular directions, perpendicular and parallel to the surface. In the latest case, the grazing-incidence technique has been used. Because this technique is very sensitive to the surface, the strain results may be re-interpreted if, the upperlOO nm are enriched in Au.

Lattice parameters and spontaneous strain in AX 2 polytypes: CdI2, PbI2 SnS2 and SnSe2

1989 ◽  
Vol 22 (6) ◽  
pp. 622-623 ◽  
Author(s):  
B. Pałosz ◽  
E. Salje
Keyword(s):  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Basal Plane ◽  
Lattice Parameter ◽  
Structural Transformations ◽  
Lattice Parameters ◽  
The Other ◽  
X Ray Diffraction ◽  
Spontaneous Strain ◽  
X Ray

Structural transformations between polytypes of a given material are expected to lead to lattice relaxations. Powder X-ray diffraction of basic AX 2 polytypes of CdI2, PbI2, SnS2 and SnSe2 showed these relaxations for the repetition unit along the stacking axis, conventionally the c axis. No variation of the lattice parameters were detected in the basal plane (001), except for CdI2 where small variations occur also for the a lattice parameter. The tensor of the spontaneous strain has its maximum component e 3 ≲ 12 × 10−4 for SnS2. The powder diffraction pattern and lattice parameters of the phases of CdI2 (2H, 12R, 4H), PbI2 (2H, 12R), SnS2 (2H, 18R, 4H) and SnSe2 (2H, 18R) are given. JCPDS Diffraction File Nos. are: 40-1468 for CdI2-12H; 40–1469 for CdI2-2H; 40-1466 for SnS2-18R, 40–1467 for SnS2-2H; 40–1465 for SnSe2-18R. The other polytypes studied in this paper have data in earlier sets of the PDF.

Sign in / Sign up

Export Citation Format

Share Document