Zirconium difluoride

1964 ◽  
Vol 17 (7) ◽  
pp. 727 ◽  
Author(s):  
FK McTaggart ◽  
AG Turnbull
Keyword(s):  
Atomic Hydrogen ◽  
Zirconium Dioxide ◽  
Chemical Properties ◽  
Thin Layers ◽  
Zirconium Tetrafluoride ◽  
Group Iva

Zirconium difluoride was prepared by the action of atomic hydrogen on thin layers of zirconium tetrafluoride, at a temperature of approximately 350�. The compound is orthorhombic in structure. It is black, tends to take up oxygen in air, and ignites readily and burns to form zirconium dioxide. Disproportionation occurs at 800� with the formation of ZrF4 and zirconium, and other chemical properties are similar to those of the known dihalides of Group IVA.

scholarly journals Sublimation Kinetics of Zirconium Tetrafluoride

2014 ◽  
Vol 1019 ◽  
pp. 398-405
Author(s):  
C.J. Pretorius ◽  
A.D. Pienaar ◽  
P.L. Crouse ◽  
H.F. Niemand
Keyword(s):  
Chemical Properties ◽  
Inert Atmosphere ◽  
Nuclear Industry ◽  
Nuclear Grade ◽  
Accurate Estimation ◽  
Chemical Waste ◽  
Hazardous Chemical ◽  
Zirconium Tetrafluoride ◽  
Sublimation Kinetics ◽  
Kinetics Of

An important step of a new process being developed for the beneficiation of the mineral zircon (Zr (Hf)SiO4) to produce nuclear grade zirconium (Zr) metal, is the separation of the Zr from the hafnium (Hf). Zr ores typically contain between 1 and 3% Hf , whereas the use of Zr metal in the nuclear industry requires a Hf content <100 ppm, owing to its high neutron-capture cross section. The separation step is therefore key in the preparation of nuclear grade Zr, which is considered to be very difficult due to the various similarities in their chemical properties. The preparation of hafnium free zirconium relies on the traditional wet separation systems, for example solvent extraction systems. In contrast to the traditional aqueous chloride systems, Necsa focusses on dry fluoride-based processes. Dry processes have the advantage of producing much less hazardous chemical waste. In the work reported her, separation is achieved by sublimation/de-sublimation in the tetrafluoride form. The tetrafluoride is prepared by fluorination of plasma dissociated zircon (PDZ or Zr (Hf)O2•SiO2) with ammonium bifluoride (ABF). The separation involves the selective sublimation of the two tetrafluorides in an inert atmosphere under controlled conditions, and subsequent similarly selective desublimation. An accurate estimation of the sublimation rates the zirconium tetrafluoride (ZrF4) and hafnium tetrafluoride (HfF4) as a function of temperature is required since this forms the basis of the development of a sublimation model to determine whether the concept under consideration is theoretically possible. The sublimation kinetics of ZrF4is reported in this paper.

scholarly journals Changes in the structure and properties of ZrO2 detonation coatings during annealing

2020 ◽  
Vol 4 (4) ◽  
pp. 319-326
Author(s):  
B.K. Rakhadilov ◽  
D.N. Kakimzhanov ◽  
G. Botabaeva ◽  
D.B. Buitkenov ◽  
N. Kantai ◽  
...  
Keyword(s):  
Zirconium Dioxide ◽  
Microscopic Analysis ◽  
Thin Layers ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Detonation Spraying ◽  
Electron Microscopic ◽  
Before And After ◽  
New Generation ◽  
High Adhesive Strength

The article studied the effect of annealing on the structure and properties of zirconium dioxide coatings obtained by detonation spraying. Detonation spraying was realized on a computerized detonation spraying complex of the new generation CCDS2000. Determined that coatings made of zirconium dioxide are characterized by high adhesive strength of adherence to the substrate. Thermal annealing of coated samples was performed at temperatures of 900-1200◦ C. It was determined that the microhardness of zirconium dioxide coatings increases by 10-25% depending on the annealing temperature after annealing. The results of nanoindentation showed that the nanohardness of the coatings after annealing at 1000◦ C increases by 50%. It was determined that after annealing at 1000◦ C, the elastic modulus of the coatings increases, which indicates a decrease in plasticity and an increase in the strength of the coatings. X-ray diffraction analysis showed that the phase composition of coatings before and after annealing consists of t-ZrO2. After annealing occurs there is an increase in the degree of t-ZrO2 tetragonality. Electron microscopic analysis showed that an increase in the number and size of micro-continuity in the form of thin layers after annealing. Determined that increase the hardness of zirconium dioxide after annealing at 900-1200◦ C is associated with a higher degree of tetragonality t-ZrO2 phase.

Structural, Morphological, and Chemical Properties of Cu/TiN Versus Cu Thin Layers for HEMT Backside Metallization

2014 ◽  
Vol 14 (3) ◽  
pp. 890-897 ◽  
Author(s):  
A. Taurino ◽  
M. A. Signore ◽  
M. Catalano ◽  
I. Farella ◽  
F. Quaranta ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Thin Layers ◽  
And Chemical Properties

scholarly journals Theoretical Evaluation of Possibility to Control Nucleation and Growth of Heteroepitaxial Carbon Films by Applied Fields

2017 ◽  
Vol 3 (3) ◽  
pp. 211 ◽  
Author(s):  
B.Z. Mansurov ◽  
G.K. Kalykova ◽  
N.N. Myasnikova ◽  
L.V. Mikhailov
Keyword(s):  
Atomic Hydrogen ◽  
Diamond Films ◽  
Chemical Properties ◽  
Copper Surface ◽  
Carbon Films ◽  
Crystalline Lattice ◽  
Oriented Growth ◽  
Theoretical Evaluation ◽  
Cell Parameters ◽  
Applied Fields

On the basis of the literature review, comparison of physical and chemical properties of materials and calculations, it was showed that the copper, saturated with hydrogen, is an appropriate substrate material<br />for heteroepitaxial growth of diamond films. The atomic hydrogen in tetrapores of copper crystalline lattice will be the crystallisation centre of carbon. Herewith the difference in lattice cell parameters between<br />the substrate and the growing diamond film is considerably reduced, i.e. epitaxial growth of crystal is possible. Besides, the disposition of tetrapores on the copper surface (111) and, respectively, of atomic hydrogen located in them, creates conditions for preferential formation of tetragonal bonds of carbon. The estimations have shown that it is possible to create conditions for preferential oriented growth of diamond films through changing the magnitude and configuration of applied fields.

scholarly journals Zirconium dioxide. Review

2021 ◽  
Vol 23 (2) ◽  
pp. 169-187
Author(s):  
Pavel P. Fedorov ◽  
Evgeniya G. Yarotskaya
Keyword(s):  
Zirconium Dioxide ◽  
Industrial Ecology ◽  
Chemical Properties ◽  
Ceramic Materials ◽  
Oxide Ceramic ◽  
Oxygen Conductivity ◽  
Heat Resistant ◽  
Zirconium Compounds ◽  
Physical And Chemical

A review of zirconium dioxide or zirconia ZrO2 is presented. The finding of zirconium compounds in nature, the physical and chemical properties of ZrO2 are given, the polymorphism of zirconium oxide, and the phase diagrams of systems with its participation are considered. The areas of application of zirconia compounds are highlighted: automotive industry, electronics industry, energy and industrial ecology, equipment manufacturing and mechanical engineering the production of zirconium-based refractories, ceramics, enamels, glass, superhard materials, applications in medicine, nuclear energetics, and many others areas of human activity. Cubic modification of zirconium dioxide, stabilized by oxides of rare earth elements,is a jewelry stone (fianite). Partially stabilized zirconium dioxide is a versatile structural material with very high resistance to crack propagation. Solid solutions of REE oxides, especially scandium, have a high oxygen conductivity, which is used in sensors for measuring the partial pressure of oxygen and in fuel cells. Attention is paid to heat-resistant oxide ceramic materials with low thermal conductivity used in the quality of heat-resistant coatings. Considerable attention was paid to the second most important mineral of zirconia - baddeleyite (ZrO2). Baddeleyite is widely used in the production of refractory materials. It is mined for the production of metallic zirconium. The achievements of Soviet and Russian scientists in thedevelopment of technologies for the production of fianite and artificial baddeleyite are presented.

Structural features of thin layers of zirconium dioxide by IR spectroscopy

1983 ◽  
Vol 39 (2) ◽  
pp. 929-933 ◽  
Author(s):  
I. I. Shaganov ◽  
�. I. Fadeeva ◽  
E. N. Eliseev ◽  
O. P. Ankudinova
Keyword(s):  
Ir Spectroscopy ◽  
Zirconium Dioxide ◽  
Structural Features ◽  
Thin Layers

scholarly journals Microcavity phonon polaritons from the weak to the ultrastrong phonon–photon coupling regime

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
María Barra-Burillo ◽  
Unai Muniain ◽  
Sara Catalano ◽  
Marta Autore ◽  
Fèlix Casanova ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Coupling Strength ◽  
Hexagonal Boron Nitride ◽  
Bulk Material ◽  
Chemical Properties ◽  
Thin Layers ◽  
Phonon Polaritons ◽  
Physical And Chemical ◽  
Photon Coupling ◽  
And Chemical Properties

AbstractStrong coupling between molecular vibrations and microcavity modes has been demonstrated to modify physical and chemical properties of the molecular material. Here, we study the less explored coupling between lattice vibrations (phonons) and microcavity modes. Embedding thin layers of hexagonal boron nitride (hBN) into classical microcavities, we demonstrate the evolution from weak to ultrastrong phonon-photon coupling when the hBN thickness is increased from a few nanometers to a fully filled cavity. Remarkably, strong coupling is achieved for hBN layers as thin as 10 nm. Further, the ultrastrong coupling in fully filled cavities yields a polariton dispersion matching that of phonon polaritons in bulk hBN, highlighting that the maximum light-matter coupling in microcavities is limited to the coupling strength between photons and the bulk material. Tunable cavity phonon polaritons could become a versatile platform for studying how the coupling strength between photons and phonons may modify the properties of polar crystals.

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