scholarly journals Structure Factors of Liquid Cu-Pb Alloys by Neutron Diffraction

1980 ◽  
Vol 35 (11) ◽  
pp. 1178-1181 ◽  
Author(s):  
Peter Lamparter ◽  
Siegfried Steeb
Keyword(s):  
Neutron Diffraction ◽  
Order Parameter ◽  
Short Range ◽  
Short Range Order ◽  
Marked Effect ◽  
Pair Correlation ◽  
Nearest Neighbour ◽  
Critical Composition ◽  
Structure Factors ◽  
Angle Scattering

Abstract By means of neutron diffraction the structure factors and pair correlation functions of five Cu-Pb alloys, Cu, and Pb in the liquid state have been determined. The nearest neighbour distances have been obtained. The marked effect of small angle scattering with the melt with critical composition (65 at % Cu) is a proof for microsegregation tendency. By comparison with a segregation model for the structure factor the short range order parameter has been derived for melts with 65 and 35 at % Cu, respectively.

scholarly journals X-Ray and Neutron Diffraction of Amorphous Nickel-Zirconium-Alloys as Prepared in Different Ways

1991 ◽  
Vol 46 (6) ◽  
pp. 491-498 ◽  
Author(s):  
L. Schultz ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Neutron Diffraction ◽  
Short Range ◽  
Melt Spinning ◽  
Short Range Order ◽  
Pair Correlation ◽  
Zirconium Alloys ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
The One

AbstractThe structure of amorphous NiχZr100-χ-alloys (Χ= 30, 31, 34, 63.7, and 65), which were produced by melt spinning (MS), mechanical alloying (MA), and sputtering (SP) was studied by X-ray- and neutron diffraction yielding structure factors, pair correlation functions, coordination numbers, atomic distances, and Warren-Cowley chemical short range order parameters. The atomic arrangement within the first coordination sphere is independent of the method of preparation while in the second and higher spheres it differs between the MS- and the MA-alloys on the one side and the SP-specimens on the other side. Thus one understands that some physical properties of the different specimens differ

Structure of Molten Mn74Si26 and Molten Mn33.5Si66.5 by Neutron Diffraction

1997 ◽  
Vol 52 (8-9) ◽  
pp. 645-649
Author(s):  
B. Sedelmeyer ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Correlation Function ◽  
Neutron Diffraction ◽  
Order Parameter ◽  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Range Order Parameter ◽  
Compound Formation ◽  
X Ray ◽  
Coordination Numbers

Abstract Molten Mn74Si26 and molten Mn33.5Si66.5 were investigated by neutron diffraction. The pair correlation function yielded, together with the X-ray results from a former paper, the partial coordination numbers, atomic distances, and the short range order parameter with the result that the atomic distribution in molten Mn33.5Si66.5 is statistical while the structure factor of molten Mn74Si26 , as obtained with neutrons, shows a strong prepeak which means rather strong compound formation.

Local Structure of the Amorphous Ni25Zr75-Alloy by Using the Isotope-Substitution Neutron Diffraction Method

1991 ◽  
Vol 46 (11) ◽  
pp. 951-954
Author(s):  
W.-M. Kuschke ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Neutron Diffraction ◽  
Local Structure ◽  
Short Range ◽  
Short Range Order ◽  
Diffraction Method ◽  
Isotopic Substitution ◽  
Isotope Substitution ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Neutron Diffraction Method

AbstractUsing neutron diffraction as well as the method of isotopic substitution the partial Bhatia-Thornton as well as the partial Faber-Ziman structure factors of amorphous Ni25Zr75 were determined. A compound forming tendency was found. The atomic distances, partial coordination numbers, and the chemical short range order parameter are evaluated.

Pb()O3-type Perovskites: Part I. Pair-correlation Theory of Order-disorder Phase Transition

1997 ◽  
Vol 12 (8) ◽  
pp. 2117-2126 ◽  
Author(s):  
Hyun M. Jang ◽  
Su-Chan Kim
Keyword(s):  
Long Range ◽  
Order Parameter ◽  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Range Order ◽  
Statistical Thermodynamic ◽  
Range Order Parameter ◽  
Long Range Order ◽  
Short Range Order Parameter

The limitation of the long-range order parameter and the necessity of the short-range order parameter for the thermodynamic description of Pb()O3-type perovskites are discussed. Based on the discussion, a statistical thermodynamic model that takes into account the configuration of the neighboring B-site ions (B′ and B″ cations) was developed. A pair-correlation approximation was used in the calculation of the configurational entropy and the long-range coulombic interaction energy between the nearest B-site ions. The theoretical calculations using Pb(Sc1/2Ta1/2)O3 (PST) and Pb(Sc1/2Nb1/2)O3 (PSN) systems indicate that the short-range order parameter persists over a wide range of temperatures examined (0–1800 K) and that there possibly occur consecutive long-range order-disorder transitions in the configuration of B-site cations. The possibility of the existence of short-range ordering above the long-range order-disorder transition temperature was also examined using the annealed PSN specimen as a typical example of Pb()O3-type perovskites.

Structural Investigation of the Metallic Glasses Mg85.5Cu14.5 and Mg70Zn30

1983 ◽  
Vol 38 (2) ◽  
pp. 142-148 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
W. Sperl ◽  
S. Steeb
Keyword(s):  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Range Order ◽  
Order Effects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Factors ◽  
Similar Chemical ◽  
Total Structure

Abstract The total structure factors as well as the total pair correlation functions for amorphous Mg85.5Cu14.5 (by neutron and X-ray diffraction) and for amorphous Mg70Zn30 (by X-ray diffraction) were determined. Both alloys show similar chemical short range order effects. From the total pair correlation function of the Mg85.5Cu14.5 glass, partial coordination numbers and atomic distances could be extracted. Comparison with the structure of crystalline Mg2Cu suggests that the short range order around the copper atoms is similar in the amorphous and the crystalline phase. The densities of both amorphous alloys were measured yielding negative excess volumina.

X-Ray Diffraction with Molten AuxMn100-x-Alloys

1995 ◽  
Vol 50 (9) ◽  
pp. 831-836
Author(s):  
R. M. Hagenmayer ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Correlation Functions ◽  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Pair Correlation Functions ◽  
X Ray ◽  
Structure Factors ◽  
Total Structure

Abstract The molten alloys Au28.5Mn71.5 and Au68Mn32 are investigated with the energy dispersive X-ray diffraction method which works rather fast so that the evaporation loss of Mn from the molten alloys is kept low. From the observed prepeak follows that both melts are compound-forming but the gold rich melt Au68Mn32 shows only 50% of the short range order existent within the Au28.5Mn71.5 melt. Total structure factors and total pair correlation functions are discussed.

A Diffraction Study of Amorphous Si0.40C 0.24N0.36

1996 ◽  
Vol 51 (12) ◽  
pp. 1179-1184 ◽  
Author(s):  
H. Uhlig ◽  
M. Frieß ◽  
J. Dürr ◽  
R. Bellissent ◽  
H.-P. Lamparter ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Diffraction Study ◽  
Chemical Bonding ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Contrast Variation ◽  
X Ray ◽  
Structure Factors ◽  
Amorphous Si

Abstract In the present work, amorphous Si0.40C0.24N0.36 samples were investigated. X-ray and neutron diffraction experiments were performed, in order to evaluate the structure factors by the method of contrast variation. The structure can be described as crosslinked Si-N-C matrices. Within these matrices SiN4 tetrahedra are predominant. Direct Si-Si contact does not occur. We report on the short range order and the nature of chemical bonding.

Neutron Diffraction Study on the Structure of Liquid Cs-Sb Alloys

1983 ◽  
Vol 38 (3) ◽  
pp. 329-335 ◽  
Author(s):  
P. Lamparter ◽  
W. Martin ◽  
S. Steeb ◽  
W. Freyland
Keyword(s):  
Neutron Diffraction ◽  
Pair Correlation ◽  
Neutron Diffraction Study ◽  
Main Peak ◽  
Continuous Change ◽  
Structure Factors ◽  
Angle Scattering ◽  
Solid Compounds ◽  
Total Structure ◽  
The Stability

Abstract By neutron diffraction experiments the total structure factors and the total pair correlation functions of liquid Cs-Sb alloys containing 85, 75, 65, and 50 at% Cs, respectively, were determined. The structural results confirm the non metallic properties of Cs-Sb melts.The correspondence of the nearest neighbour atomic arrangement in liquid Cs75Sb25 and in the solid compound semiconductor Cs3Sb suggests a similar type of bonding, namely by valence bonds and ionic forces simultaneously. The stability of this compound in the molten state leads to a microsegregation tendency between compound forming regions and excess Cs in the concentration range from pure Cs up to 25 at% Sb, which is established by a small angle scattering effect.Proceeding from Cs75Sb25 to Cs50Sb50, a continuous change in the structure takes place. Covalently bonded Sb chains are formed just as found in the corresponding solid compounds ASb (A = alkali metal). An additional diffraction peak in front of the main peak of the structure factors within this composition range implies the formation of rather large molecular clusters in the alloys.

Structure of Molten Sn-Zn-Alloys by Means of Neutron Diffraction

1978 ◽  
Vol 33 (10) ◽  
pp. 1151-1153 ◽  
Author(s):  
Walter Knoll ◽  
Siegfried Steeb
Keyword(s):  
Neutron Diffraction ◽  
Small Angle ◽  
Correlation Functions ◽  
Pair Correlation ◽  
Small Angle Scattering ◽  
Pair Correlation Functions ◽  
Structure Factors ◽  
Angle Scattering ◽  
Total Structure ◽  
Zn Alloys

Abstract Neutron diffraction experiments were performed with four molten Sn-Zn-alloys and the two molten elements Sn and Zn. The total structure factors and the pair correlation functions are given. The observed small angle scattering leads to the result that pairs of equal atoms predominate within the range of medium concentrations.

Structure of Molten Bi-Zn-Alloys by Means of Neutron Diffraction

1983 ◽  
Vol 38 (4) ◽  
pp. 395-398 ◽  
Author(s):  
W. Knoll ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Neutron Diffraction ◽  
Concentration Dependence ◽  
Correlation Functions ◽  
Pair Correlation ◽  
Nearest Neighbour ◽  
Pair Correlation Functions ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Total Structure ◽  
Zn Alloys

Neutron diffraction experiments were performed with five molten Bi-Zn-alloys and the two molten elements Bi and Zn. The total structure factors and the pair correlation functions are given. The concentration dependence of the experimental nearest neighbour distances and the experimental coordination numbers is in accordance with the segregation behaviour prevailing in these melts.

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