Mechanochemical Synthesis of ZrTiO4 Precursor from Inhomogeneous Mixed Gels

1994 ◽  
Vol 346 ◽  
Author(s):  
Tetsuhiko isobe ◽  
Yutaka Okamoto ◽  
Mamoru Senna
Keyword(s):  
Raman Spectroscopy ◽  
Mechanical Stress ◽  
Mechanochemical Synthesis ◽  
Short Range ◽  
Room Temperature ◽  
Hydroxyl Groups ◽  
Short Range Ordering ◽  
Two Phases ◽  
Mechanochemical Reactions ◽  
Metallic Species

ABSTRACTEffects of vibration ball-milling of a powdered mixture of two gels, prepared from mixing ZrO2 andTiO2 sols, on crystallization processes during heating are studied in order to elucidate enhanced mechanochemical reactions with the aid of hydroxyl groups. TiO2 (anatase) and ZrO2 (tetragonal) crystallized at 698 K and 712 K, respectively, when heating non-milled gel mixture at 10 K min1 in air. Few reactions between the two phases were detected below 1023 K. After vibro-milling a powdered gel mixture at room temperature for 3 to 30 h, ZrTiO4 (orthorhombic) crystallized directly from non-crystalline precursors on heating to 1023 K. The fraction of crystallizedZrTi04, determined by Raman spectroscopy, increased linearly with increasing the index of micro-homogeneity for non-heated gels. We suggest that short-range ordering of ZrTiO4 rather than crystallization of individual oxides occurs through the non-thermal atomic movement between different metallic species under mechanical stress.

scholarly journals Short‐range ordering in the Li‐rich disordered rock salt cathode material Li 2 VO 2 F revealed by Raman spectroscopy

2020 ◽  
Vol 51 (10) ◽  
pp. 2095-2101 ◽  
Author(s):  
Nataliia Mozhzhukhina ◽  
Jolla Kullgren ◽  
Christian Baur ◽  
Olof Gustafsson ◽  
William R. Brant ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cathode Material ◽  
Rock Salt ◽  
Short Range ◽  
Short Range Ordering

Room-temperature-deformation-induced chemical short-range ordering in a supersaturated ultrafine-grained Al-Zn alloy

2022 ◽  
Vol 210 ◽  
pp. 114423
Author(s):  
Z.Z. Song ◽  
R.M. Niu ◽  
X.Y. Cui ◽  
E.V. Bobruk ◽  
M. Murashkin ◽  
...  
Keyword(s):  
Short Range ◽  
Room Temperature ◽  
Temperature Deformation ◽  
Ultrafine Grained ◽  
Short Range Ordering ◽  
Zn Alloy

Aging-induced double hysteresis loops in bismuth-doped (Ba,Ca)TiO3 ferroelectric ceramics

2009 ◽  
Vol 24 (10) ◽  
pp. 3073-3077 ◽  
Author(s):  
Sining Yun ◽  
Xiaoli Wang ◽  
Jing Shi ◽  
Delong Xu
Keyword(s):  
Solid State ◽  
Point Defects ◽  
Short Range ◽  
Room Temperature ◽  
Domain Switching ◽  
Hysteresis Loops ◽  
Ferroelectric Ceramics ◽  
Solid State Reaction Technique ◽  
Conventional Solid State Reaction ◽  
Short Range Ordering

Bismuth-doped (Ba1−xCax)TiO3 ceramics (x = 0.10, Bi-BCT) were prepared by a conventional solid-state reaction technique. An abnormal double-like hysteresis polarization–electric (P–E) loop was observed at room temperature for aged Bi-BCT. Raman scattering gives critical evidence for the formation of O2− vacancies in Bi-BCT. The change from the single P–E loops in the fresh samples to the double loops in the aged samples excludes the existence of a ferroelectric–antiferroelectric transition in Bi-BCT. A reversible domain switching mechanism resulting from a symmetry-conforming short-range ordering of point defects gives a reasonable explanation for the naturally age-induced double-like P–E loops in Bi-BCT.

Room-Temperature Short-Range Ordering in Fe-Si Alloys Observed by Internal Friction

2008 ◽  
Vol 137 ◽  
pp. 83-90
Author(s):  
Fernando González ◽  
Daniel Ruiz ◽  
Yvan Houbaert
Keyword(s):  
Internal Friction ◽  
Cold Rolling ◽  
Short Range ◽  
Room Temperature ◽  
Ageing Time ◽  
Low Carbon ◽  
New Production ◽  
Short Range Ordering ◽  
Si Content ◽  
Ageing Phenomenon

Research performed at Ghent University, regarding new production methods for electrical steel, has shown that high silicon steel suffers an ageing phenomenon at room temperature. Recent studies carried out by the same group using different analysis techniques (Mossbauer spectroscopy, neutron diffraction, etc) brought to light a probable process of ordering towards the D03-structure, which is responsible for the observed low ductility during cold rolling and makes the processing of steel extremely difficult. In addition, the Si-steels become more brittle as the delay time between hot and cold rolling is increased. Frequency dependent internal friction (FDIF) studies were performed on different Fe - Si alloys with a Si content varying from 3.73 at. % to 8.7 at. % immediately after several thermal treatments and compared with ultra-low carbon steel. The evolution of relaxation peaks during the IF measurements, performed at constant room temperature, helps to understand the ageing mechanisms. Three processes have been observed: firstly, as expected, addition of Si reduces the carbon Snoek peak. Secondly, a peak associated to C - Si is formed. Thirdly, a low frequency peak associated with Zener relaxation (Si atom pairs) appears for a content of approximately 3.77 wt. % Si. The two latter peaks decrease with ageing time and in the case of the Zener peak there is a notable displacement to higher frequencies with a small increase of the Si content. The reduction of the peaks during the ageing after annealing is more noticeable in quenched specimens than in air cooled ones, and in furnace cooled specimens the reduction is even smaller, indicating that the process is really an ageing phenomenon. Room temperature short-range ordering might explain both the lowering of the Zener peak and the observed macroscopic embrittlement.

The Comparative Mössbauer Analysis of Superfine Structure of Hadfield Steel upon Different Kinds of Severe Deformation

2011 ◽  
Vol 319-320 ◽  
pp. 13-23 ◽  
Author(s):  
V.A. Shabashov ◽  
A.E. Zamatovsky ◽  
L.G. Korshunov ◽  
A.V. Litvinov
Keyword(s):  
Plastic Deformation ◽  
Short Range ◽  
Room Temperature ◽  
Precipitation Hardening ◽  
Effective Field ◽  
Hadfield Steel ◽  
Magnetic Characteristics ◽  
Short Range Ordering ◽  
Superfine Structure ◽  
Mössbauer Analysis

Severe plastic deformation (friction, compression shear, filing or rolling) of Hadfield steel leads to the growth of the internal effective field on 57Fe cores, removal of the magnetic degeneracy in spectra, and the extension of the paraprocess up to room temperature. The observed change of the magnetic characteristics is explained by the deformation-induced redistribution of carbon and short-range ordering of carbon and manganese. Since the magnetic degeneracy is removed in the Hadfield steel upon deformation, it is possible to consider a mechanism of magnetic precipitation hardening, which is realized in local magnetically ordered regions of the structure containing Mn-C pairs.

Short-range ordering inβ−YH2+δandβ−YD2+δthin films studied by Raman spectroscopy

2004 ◽  
Vol 69 (13) ◽  
Author(s):  
A.-M. Carsteanu ◽  
M. Rode ◽  
D. Zur ◽  
A. Borgschulte ◽  
H. Schröter ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Short Range ◽  
Short Range Ordering

Exploring the Biological Protective Role of Carotenoids by Raman Spectroscopy: Mechanical Stress of Cells

2019 ◽  
Vol 64 (1-2) ◽  
pp. 75-82
Author(s):  
F. Nekvapil ◽  
◽  
Cs. Müller Molnár ◽  
S. Tomšić ◽  
S. Cintă Pinzaru ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Mechanical Stress ◽  
Protective Role

Micro-Raman Spectroscopy Evaluation of the Local Mechanical Stress in Shallow Trench Isolation CMOS Structures: Correlation with Defect Generation and Diode Leakage

1998 ◽  
Author(s):  
I. De Wolf ◽  
G. Groeseneken ◽  
H.E. Maes ◽  
M. Bolt ◽  
K. Barla ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Mechanical Stress ◽  
Defect Formation ◽  
Active Area ◽  
Wet Oxidation ◽  
Leakage Currents ◽  
Shallow Trench Isolation ◽  
Micro Raman Spectroscopy ◽  
Silicon Devices ◽  
Trench Isolation

Abstract It is shown, using micro-Raman spectroscopy, that Shallow Trench Isolation introduces high stresses in the active area of silicon devices when wet oxidation steps are used. These stresses result in defect formation in the active area, leading to high diode leakage currents. The stress levels are highest near the outer edges of line structures and at square structures. They also increase with decreasing active area dimensions.

scholarly journals Mechanochemistry of fluoride solids: from mechanical activation to mechanically stimulated synthesis

ChemTexts ◽  
2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Gudrun Scholz
Keyword(s):  
Mechanical Activation ◽  
Mechanochemical Synthesis ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Technical Equipment ◽  
Metal Compounds ◽  
Potential Applications ◽  
The Given ◽  
Mechanochemical Reactions

Abstract This lecture text is focused on the comparatively young field of mechanochemistry of fluoride solids, considering both their mechanical activation and their mechanochemical synthesis. Beside a literature survey, the mechanochemical synthesis of binary fluorides MF2, MF3, of complex fluorides MMgF4, of solid solutions MaxMb1−xF2 or M1−xLnxF2+x (Ln: Y, Eu) and of fluorine-containing coordination polymers is presented. Owing to their interesting potential applications in the field of fluoride ion conductivity or luminescence properties when doped, most of the given examples are alkaline earth metal compounds. A short historical survey, remarks on peculiarities and consequences of mechanical activation as well as the necessary technical equipment for mechanochemical reactions precede the section. Graphic abstract

Sign in / Sign up

Export Citation Format

Share Document