An X-ray and Neutron Scattering Study of the Structure of Zinc Vanadate Glasses

2001 ◽  
Vol 56 (6-7) ◽  
pp. 478-488
Author(s):  
Uwe Hoppe ◽  
Rainer Kranold ◽  
Emil Gattef ◽  
Jörg Neuefeind ◽  
David A. Keen
Keyword(s):  
Neutron Diffraction ◽  
Coordination Number ◽  
Short Range ◽  
Short Range Order ◽  
X Ray ◽  
Coordination Numbers ◽  
Gaussian Functions ◽  
Scattering Study ◽  
Neutron Scattering Study ◽  
Vanadate Glasses

Abstract The short-range order of vitreous V20 5 and of three (Zn0)Jt(V20 5)1_x glasses with x = 0.2, 0.4, and 0.5 is studied by X-ray and neutron diffraction experiments where the change of the contrast allows to resolve the V -0 and Z n -0 correlations. The V -0 and the Z n -0 first-neighbor peaks are approximat­ ed by several Gaussian functions. In case of vitreous V20 5 two obvious V -0 distances exist which are related with V 0 4 and V 0 5 units. With ZnO additions the V -O coordination number decreases from 4.4 in vitreous V20 5 to 4.0 in the metavanadate glass where the strongest decrease of the fraction of V 0 5 units is found for glasses of * < 0.2. Dominantly, the V 0 5 groups are linked with the neighboring units by comers. The Z n-0 coordination numbers of the modified glasses are about five with closest dis­ tances of = 0.200 nm.

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

Short Range Structure of Amorphous Ni50Ta50-Alloys by Means of X-Ray- and Neutron-Diffraction

1992 ◽  
Vol 47 (7-8) ◽  
pp. 826-832 ◽  
Author(s):  
H. Uhlig ◽  
L. Rohr ◽  
H.-J. Güntherodt ◽  
P. Fischer ◽  
P. Lamparter ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Short Range ◽  
Short Range Order ◽  
Nearest Neighbor ◽  
Range Order ◽  
Partial Structure ◽  
X Ray ◽  
Coordination Numbers ◽  
Binding Behavior ◽  
Structure Factors

Abstract Amorphous Ni50Ta50-samples with their high crystallization temperature of 985 K were investigated. To evaluate the three partial structure factors of amorphous Ni50Ta50 one X-ray diffraction experiment was performed with Ni50Ta50 and two neutron diffraction experiments with Co10Ni40Ta50 and with Ni50Ta50, respectively. The Bhatia-Thornton partial structure factor SCC(Q) indicates rather strong chemical short range order which also explains the premaximum observed in the Faber-Ziman partial SNiNi(Q)-function. The nearest neighbor distance is 2.82 Å for Ni-Ni, 2.91 Å for Ta-Ta, and is shortest for Ni-Ta, 2.44 Å. The coordination numbers are NNiNi = 4.9, NTaTa = 8.2, and NNiTa = 6.0. We report on the chemical short range order and the possible binding behavior in a-Ni50Ta50 and compare the present results with those reported in the literature on a-Ni40Ti60 as well as on a-Ni55Ta45

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.

Local Atomic Structures in Amorphous and Quasicrystalline Zr70Ni10Pt20and Zr80Pt20Alloys by the Anomalous X-ray Scattering Method

2000 ◽  
Vol 644 ◽  
Author(s):  
Eiichiro Matsubara ◽  
Takahiro Nakamura ◽  
Masaki Sakurai ◽  
Muneyuki Imafuku ◽  
Shigeo Sato ◽  
...  
Keyword(s):  
Short Range ◽  
Short Range Order ◽  
Nearest Neighbor ◽  
Scattering Method ◽  
X Ray ◽  
Coordination Numbers ◽  
Atomic Structures ◽  
X Ray Scattering ◽  
Icosahedral Clusters ◽  
Ray Scattering

AbstractLocal atomic structures around Zr and Pt in a quasicrystalline Zr80Pt20alloy, and amorphous and quasicrystalline Zr70Ni10Pt20alloys have been determined by the anomalous x-ray scattering (AXS) method. A distinct prepeak observed in an intensity profile of the amorphous Zr70Ni10Pt20alloy indicates existence of strong chemical short-range order (CSRO) clusters in the amorphous phase. Total coordination numbers around Zr and Pt in a nearest neighbor region in both alloys have been evaluated. The values around Pt are almost equal to 12 in the amorphous and quasicrystalline states suggest formation of icosahedral clusters around Pt. Some of crystalline structures formed from the quasicrystalline phases by annealing consist of icosahedral clusters of Zr and Ni atoms, or polyhedral clusters of Zr and Pt atoms similar with icosahedral clusters. The present result appears to support that the phase transformation from the amorphous to the crystal through the quasicrystal is explained by the icosahedral CSRO clusters in the amorphous and quasicrystalline states.

Neutron- and X-ray-Diffraction Study on the Structure of Amorphous Co25Ti75

1987 ◽  
Vol 42 (1) ◽  
pp. 7-12 ◽  
Author(s):  
A. Müller ◽  
E. Bühler ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Diffraction Study ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Melt Spin

Amorphous Co25Ti75 could be produced using the melt-spin-technique. A neutron- and a X-ray-diffraction experiment was performed. Assuming SNC ≡ 0 the partial Bhatia Thornton structure factors SNN and SCC as well as the partial coordination numbers were calculated. The discussion yields the atomic distances and the chemical short range order parameters.

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