scholarly journals Особенности фазообразования TbBO-=SUB=-3-=/SUB=- при изотермических отжигах

2019 ◽  
Vol 61 (2) ◽  
pp. 340
Author(s):  
И.М. Шмытько
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Annealing Temperature ◽  
Initial Mixture ◽  
Amorphous Precursor ◽  
Two Phase ◽  
X Ray ◽  
Annealing Temperatures ◽  
Low Temperature Annealing ◽  
Hypothetical Explanation

AbstractDetailed X-ray studies of changes in the structure of terbium orthoborate TbBO_3 in the course of successive high-temperature isothermal annealing of the initial mixture in the form of an amorphous precursor and in the form of a homogenized mixture of microcrystalline Tb_7O_12 and B_2O_3 powders have been carried out. It is shown that the formation of TbBO_3 crystals in both cases occurs through the formation of intermediate two-phase states. Particularly, the triclinic high-temperature ν-TbBO_3 phase is formed already at the first crystallization stages (about 600°C) almost simultaneously with the equilibrium vaterite modification of TbBO_3 (sp. gr. P 63/ mmc ) during low-temperature annealing of an amorphous precursor, which transforms into the vaterite modification at an annealing temperature of 850°C. The phase of monoclinic terbium trioxoborate TbB_3O_6 is formed at the first stages of phase formation (about 800°C) almost simultaneously with the vaterite phase when the feedstock is annealed in the form of a homogenized mixture of microcrystalline Tb_7O_12 and B_2O_3 powders. It also transforms into the vaterite modification at an annealing temperature of 950°, which is preserved up to the highest annealing temperatures in the experiment (1200°C). A hypothetical explanation of the formation of such two-phase states during low-temperature annealing of the feedstock and their disappearance at higher annealing temperatures is proposed.

scholarly journals Influence of low temperature annealing on Nickel RTDs designed for heat flux sensing

2019 ◽  
Author(s):  
Youssef Mokadem ◽  
Sylvie Bégot ◽  
François Lanzetta ◽  
Jean-Yves Rauch ◽  
Aymen Zribi ◽  
...  
Keyword(s):  
Thin Films ◽  
Heat Flux ◽  
Low Temperature ◽  
Temperature Coefficient ◽  
Annealing Temperature ◽  
Adhesive Layer ◽  
Sem Images ◽  
Nickel Thin Films ◽  
Annealing Temperatures ◽  
Low Temperature Annealing

In this paper, we study the influence of annealing on the performance of Resistive Temperature Detectors made from Nickel thin films. The aimed application is heat flux sensing. The substrate is made of Borofloat glass with a Chromium adhesive layer. Several annealing temperatures between 150°C and 300°C are applied to this assembly. The thin films as deposited and after annealing are analyzed through SEM images. The evolution of the resistance and the temperature coefficient of the sensor are discussed. An annealing temperature is selected that ensures the repeatability of measurements.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

The Application of X-Ray Diffraction at Elevated Temperatures to Study the Mechanism of Formation of Sodium Tripolyphosphate

1961 ◽  
Vol 5 ◽  
pp. 276-284
Author(s):  
E. L. Moore ◽  
J. S. Metcalf
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Amorphous Phase ◽  
Elevated Temperatures ◽  
Sodium Tripolyphosphate ◽  
X Ray Diffraction ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Temperature Form ◽  
High Temperature Form

AbstractHigh-temperature X-ray diffraction techniques were employed to study the condensation reactions which occur when sodium orthophosphates are heated to 380°C. Crystalline Na4P2O7 and an amorphous phase were formed first from an equimolar mixture of Na2HPO4·NaH2PO4 and Na2HPO4 at temperatures above 150°C. Further heating resulted in the formation of Na5P3O10-I (high-temperature form) at the expense of the crystalline Na4P4O7 and amorphous phase. Crystalline Na5P3O10-II (low-temperature form) appears after Na5P3O10-I.Conditions which affect the yield of crystalline Na4P2O7 and amorphous phase as intermediates and their effect on the yield of Na5P3O10 are also presented.

scholarly journals X-ray diffraction analysis of kaolin M1 and M2 via the Williamson–Hall and Warren–Averbach methods

2021 ◽  
pp. 174751982098472
Author(s):  
Lalmi Khier ◽  
Lakel Abdelghani ◽  
Belahssen Okba ◽  
Djamel Maouche ◽  
Lakel Said
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Mechanical Resistance ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Mullite Phase

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

The Evaluation of TiTe2 as a Diffusion Barrier in the Formation of Low Thermal Conductivity Nanolaminates with Bi2Te3 and Sb2Te3

2010 ◽  
Vol 74 ◽  
pp. 38-47
Author(s):  
Clay Mortensen ◽  
Paul Zschack ◽  
David C. Johnson
Keyword(s):  
Thermal Conductivity ◽  
Diffusion Barrier ◽  
Self Assembly ◽  
Low Temperatures ◽  
Annealing Temperature ◽  
The Self ◽  
High Angle ◽  
X Ray Diffraction ◽  
Amorphous Precursor ◽  
X Ray

The evolution of designed [(Ti-Te)]x[(Sb-Te)]y, [(Bi-Te)]x[(Sb-Te)]y, [(Ti-Te)]w[(Bi-Te)]x[(Sb-Te)]y and [(Ti-Te)]w[(Bi-Te)]x[(Ti-Te)]y[(Sb-Te)]z precursors were followed as a function of annealing temperature and time using both low and high angle x-ray diffraction techniques to probe the self assembly into nanolaminate materials. The [(Bi-Te)]x[(Sb-Te)]y precursors were found to interdiffuse at low temperatures to form a (BixSb1-x)2Te3 alloy. The [(Ti-Te)]x[(Bi-Te)]y and [(Ti-Te)]x[(Sb-Te)]y precursors formed ordered nanolaminates [{(TiTe2)}1.35]x[Bi2Te3]y and [{(TiTe2)}1.35]x[Sb2Te3]y respectively. The [(Ti-Te)]w[(Bi-Te)]x[(Sb-Te)]x precursors formed [{(TiTe2)}1.35]w[(Bi0.5Sb0.5)2Te3]2x nanolaminates on annealing, as the bismuth and antimony layers interdiffused. Over the range of TiTe2 thicknesses used in [(Ti-Te)]w[(Bi-Te)]x[(Ti-Te)]y[(Sb-Te)]z precursors, Bi and Sb were found to interdiffuse through the 2-4 nm thick Ti-Te layers, resulting in the formation of (BixSb1-x)2Te3 alloy layers as part of the final nanolaminated products. When the Bi-Te and Sb-Te thicknesses were equal in the amorphous precursors, symmetric [{(TiTe2)}1.35]m[(Bi0.5Sb0.5)2Te3]n nanolamiantes were formed. When the thicknesses of Bi-Te and Sb-Te layers were not equal in the amorphous precursor, asymmetric [(TiTe2)1.35]m[(BixSb1-x)2Te3]n[(TiTe2)1.35]m[(BixSb1-x)2Te3]p nanolaminates were formed. These results imply that to form (A)w(B)x(C)y nanolaminates using designed layered precursors all three components must be immiscible. To form (A)x(B)y(A)x(C)z nanolaminates, the components must be immiscible or the precursor to the A component and the A component itself must be an effective interdiffusion barrier preventing B and C from mixing.

Microstructures of two-phase Ti–Cr alloys containing the TiCr2 Laves phase intermetallic

1997 ◽  
Vol 12 (6) ◽  
pp. 1472-1480 ◽  
Author(s):  
Katherine C. Chen ◽  
Samuel M. Allen ◽  
James D. Livingston
Keyword(s):  
Laves Phase ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
Phase Growth ◽  
Two Phase ◽  
X Ray ◽  
Lattice Constants ◽  
Annealing Temperatures ◽  
Transmission Electron ◽  
Phase Intermetallic

Microstructures of two-phase Ti–Cr alloys (Ti-rich bcc + TiCr2 and Cr-rich bcc + TiCr2) are analyzed. A variety of TiCr2 precipitate morphologies is encountered with different nominal alloy compositions and annealing temperatures. Lattice constants and crystal structures are determined by x-ray diffraction (XRD) and transmission electron microscopy (TEM). Orientation relationships between the beta bcc solid solution and C15 TiCr2 Laves phase are understood in terms of geometrical packing, and are consistent with a Laves phase growth mechanism involving twinning.

Low-Temperature Annealing of the X-Ray-Induced Volume Expansion and Coloration of LiF

1964 ◽  
Vol 134 (2A) ◽  
pp. A485-A491 ◽  
Author(s):  
S. Mascarenhas ◽  
D. A. Wiegand ◽  
R. Smoluchowski
Keyword(s):  
Low Temperature ◽  
Volume Expansion ◽  
X Ray ◽  
Low Temperature Annealing

scholarly journals Crystal Chemistry and Luminescence Properties of Eu-Doped Polycrystalline Hydroxyapatite Synthesized by Chemical Precipitation at Room Temperature

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 250 ◽  
Author(s):  
Francesco Baldassarre ◽  
Angela Altomare ◽  
Nicola Corriero ◽  
Ernesto Mesto ◽  
Maria Lacalamita ◽  
...  
Keyword(s):  
Fourier Transform ◽  
High Temperature ◽  
Inductively Coupled Plasma ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled

Europium-doped hydroxyapatite Ca10(PO4)6(OH)2 (3% mol) powders were synthesized by an optimized chemical precipitation method at 25 °C, followed by drying at 120 °C and calcination at 450 °C and 900 °C. The obtained nanosized crystallite samples were investigated by means of a combination of inductively coupled plasma (ICP) spectroscopy, powder X-ray diffraction (PXRD), Fourier Transform Infrared (FTIR), Raman and photoluminescence (PL) spectroscopies. The Rietveld refinement in the hexagonal P63/m space group showed europium ordered at the Ca2 site at high temperature (900 °C), and at the Ca1 site for lower temperatures (120 °C and 450 °C). FTIR and Raman spectra showed slight band shifts and minor modifications of the (PO4) bands with increasing annealing temperature. PL spectra and decay curves revealed significant luminescence emission for the phase obtained at 900 °C and highlighted the migration of Eu from the Ca1 to Ca2 site as a result of increasing calcinating temperature.

ZrN Diffusion Barrier in Aluminum Metallization Schemes

1982 ◽  
Vol 18 ◽  
Author(s):  
L. Krusin-Elbaum ◽  
M. Wittmer ◽  
C.-Y. Ting ◽  
J. J. Cuomo
Keyword(s):  
Grain Size ◽  
Diffusion Barrier ◽  
Annealing Temperature ◽  
Barrier Properties ◽  
Metal Nitrides ◽  
X Ray ◽  
Annealing Temperatures ◽  
Fine Grain ◽  
Transmission Electron ◽  
Aluminum Metallization

We have studied reactively sputtered ZrN, the most thermally stable of the refractory metal nitrides, for its diffusion barrier properties in aluminum metallization schemes with Rutherford backscattering spectroscopy and transmission electron microscopy (TEM). We find this compound to be very effective against aluminum diffusion up to 500 °C, independently of substrate temperature during sputtering. The useful temperature range can be extended by 50 °C with proper preannealing prior to aluminum deposition. The TEM study of the ZrN grain size as a function of annealing temperature revealed that the grain size does not change significantly upon annealing and that the grains are relatively small even at the highest annealing temperatures (about 300 Å at 900 °C). In addition, for annealing temperatures of and below 500 °C large portions of ZrN films were found to be of either amorphous or extremely fine–grain material, thus inhibiting the diffusion along grain boundaries. The presence of Zr3Al4Si5 ternary compound in samples annealed at 600 °C, as determined by X-ray analysis, may suggest that the ZrN barrier fails by decomposition of the film by aluminum.

PHASE EVOLUTION AND MAGNETIC PROPERTIES OF FEPT-PTTE2 NANORODS

2009 ◽  
Vol 23 (17) ◽  
pp. 3573-3578
Author(s):  
QINGYU YAN ◽  
AIDONG LI
Keyword(s):  
Magnetic Properties ◽  
Phase Transformation ◽  
High Temperature ◽  
Annealing Temperature ◽  
Phase Evolution ◽  
Polyol Process ◽  
Phase Ratio ◽  
High Temperature Annealing ◽  
Two Phase

FePt - PtTe 2 two phase nanorods have been produced by a polyol process. The shape and magnetic properties of two phase nanorods with different phase ratio are investigated. L10 phase transformation of FePt in the nanorods has been accomplished at annealing temperature as low as 400 °C with Hc above 500mT. High temperature annealing causes the disintegration of the nanorods due the melting/evaporation of Te element.

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