Atomic Structure of Rare Earth Si-Al-O-N Glasses

1998 ◽  
Vol 53 (5) ◽  
pp. 259-264 ◽  
Author(s):  
H. Uhlig ◽  
M.-J. Hoffmann ◽  
S. Steeb
Keyword(s):  
Rare Earth ◽  
Neutron Diffraction ◽  
Atomic Structure ◽  
Pair Correlation ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
X Ray ◽  
Structure Factors ◽  
Total Structure

Abstract In this paper the results of X-ray diffraction experiments of Ln-Si-Al-O-N (Ln = La, Gd, Yb) glasses are presented. Total structure factors and pair correlation functions allow the determination of the first coordination sphere of Ln atoms. The bond lengths observed correspond to the ionic radii of the Ln-ions surrounded by oxygen and nitrogen atoms. The presence of non-bridging nitrogen is discussed together with results of neutron diffraction, NMR-experiments and XPS-studies of other authors.

Investigation of Mg-Bi Melts by Means of X-Ray- and Neutron Diffraction

1979 ◽  
Vol 34 (12) ◽  
pp. 1398-1403 ◽  
Author(s):  
Michael Weber ◽  
Siegfried Steeb ◽  
Peter Lamparter
Keyword(s):  
Neutron Diffraction ◽  
Pair Correlation ◽  
Distribution Functions ◽  
Nearest Neighbour ◽  
X Ray Diffraction ◽  
Neighbour Distance ◽  
X Ray ◽  
Structure Factors ◽  
Nearest Neighbours ◽  
Total Structure

Abstract Neutron diffraction experiments were done on Mg-Bi melts with eight compositions. From the measured intensities total structure factors and pair correlation functions as well as radial atomic distribution functions were calculated. The concentration dependence of the measured nearest neighbour distance and measured coordination number indicates the preference of unlike nearest neighbours within the Mg-Bi melts.The neutron-intensity curves show premaxima at q ≅ 1.6 Å-1. X-Ray diffraction experiments performed on melts with three different compositions also yield corresponding premaxima. It could be shown that the premaximum intensity from the X-Ray as well as from the neutron experiment corresponds to the assumption that the premaxima are caused by modulation of the monotonic Laue scattering.

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.

X-Ray Diffraction Study on the Structure of the Metallic Glasses Mg84Ni16 and Mg30Ca70

1983 ◽  
Vol 38 (11) ◽  
pp. 1206-1209 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Metallic Glasses ◽  
Pair Correlation ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Short Range Ordering ◽  
Gaussian Fit ◽  
Total Structure

The total structure factors as well as the total pair correlation functions of amorphous Mg84Ni16 and Mg30Ca70 were determined by X-ray diffraction. The Mg-Ni glass shows rather strong chemical short range ordering. By Gaussian fit of the total pair correlation function partial coordination numbers and atomic distances were obtained. Similar surrounding of the Ni atoms in the amorphous phase and in crystalline Mg2Ni was found. The structural features of the Mg-Ca glass differ from those of the Mg-Ni glass

Structure of Sputtered Amorphous Zr-Hf-Si Alloys

1999 ◽  
Vol 54 (12) ◽  
pp. 699-703
Author(s):  
A. Pojtinger ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Amorphous Alloys ◽  
Short Range ◽  
Pair Correlation ◽  
Isomorphous Substitution ◽  
X Ray Diffraction ◽  
Partial Functions ◽  
X Ray ◽  
Structure Factors ◽  
Reverse Monte Carlo Simulation ◽  
Total Structure

Abstract Amorphous (Zr,Hf)37Si63 alloys were produced by sputtering. Their total structure factors were determined by X-ray diffraction. Using the methods of isomorphous substitution and Reverse Monte Carlo simulation, the partial pair correlation functions were obtained. The results were compared with the partial functions of amorphous Ti40Si60. In the amorphous alloys under investigation the transition metal -metalloid correlation dominates the short range order.

Structure of Mn-Si-Melts by Means of X-Ray Diffraction

1983 ◽  
Vol 38 (10) ◽  
pp. 1093-1097 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
B. Sedelmeyer ◽  
S. Steeb
Keyword(s):  
Structure Factor ◽  
Melt Spinning ◽  
Pair Correlation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Glass Forming ◽  
Structure Factors ◽  
Total Structure Factor ◽  
Total Structure

Abstract The binary molten alloys Mn74Si26 and Mn33.5Si66.5 have been investigated by means of X-ray diffraction. The total structure factors as well as the total pair correlation functions were evaluated. The interatomic distances and total coordination numbers are given. The structural results for Mn74Si26 were compared to those for amorphous Mn74Si23P3 and for a tetrahedral packing model. A pronounced shoulder on the second maximum of the structure factor, which normally is characteristic for the curves obtained with amorphous substances was observed for the Mn74Si26 melt. With the Mn33.5Si66.5 melt, however, this feature cold not be observed. Since with this concentration no glass forming by melt spinning is possible, a correlation between the shape of the second maximum of a total structure factor and the glass forming ability of the corresponding melt is suggested.

On the Structure of Moltenand Amorphous Cu84.3P15.7by X-ray Diffraction

1995 ◽  
Vol 50 (10) ◽  
pp. 931-934
Author(s):  
R. M. Hagenmayer ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Room Temperature ◽  
Pair Correlation ◽  
Amorphous State ◽  
Radius Of Gyration ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surrounding Matrix ◽  
Structure Factors ◽  
Angle Scattering ◽  
Total Structure

AbstractThe atomic distances in molten Cu84.3P15.7 at 770°C are smaller than those in the amorphous state at room temperature. This follows from the pair correlation functions obtained from the total structure factors. Since the weighting factors are rather inconvenient, it is not possible to draw conclusions concerning short range order in amorphous or molten Cu84.3P15.7.Small angle scattering with the amorphous specimen shows up regions with a radius of gyration of 14 Å, whose density is different from the surrounding matrix.

Determination of the Partial Structure Factors of the Metallic Glass Fe80B20

1981 ◽  
Vol 36 (10) ◽  
pp. 1032-1044 ◽  
Author(s):  
E. Nold ◽  
P. Lamparter ◽  
H. Olbrich ◽  
G. Rainer-Harbach ◽  
S. Steeb
Keyword(s):  
Metallic Glass ◽  
Fourier Transforms ◽  
Pair Correlation ◽  
X Ray Diffraction ◽  
Partial Structure ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Good Agreement

By X-ray diffraction and neutron diffraction using the isotopic substitution method, the partial structure factors /SFeFe, SFeB, and SBB well as SNN, SCC, and SNC were determined for the metallic glass Fe80B20. The Fourier-transforms yielded the pair correlation functions Gij from which the atomic distances and the partial coordination numbers were calculated. The partial coordination numbers are in good agreement with those of the metastable Fe3B-phase, which is the first crystallization product formed during annealing of the metallic glass Fe80B20. The chemical short range order parameter amounts to 100%, thus indicating perfect chemical order.

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

Sign in / Sign up

Export Citation Format

Share Document