STRUCTURAL TRANSITION OF NANOCRYSTALLINE TiO2

2011 ◽  
Vol 10 (01n02) ◽  
pp. 59-63 ◽  
Author(s):  
MANORANJAN KAR ◽  
N. RAMA KRISHNAN ◽  
INDRAJIT TALUKDAR ◽  
K. ACHARYYA
Keyword(s):  
Crystallite Size ◽  
Bulk Material ◽  
Anatase Phase ◽  
Average Crystallite Size ◽  
Rutile Phase ◽  
High Energy ◽  
Nanocrystalline Tio2 ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Xrd Patterns

Nanocrystalline TiO 2 sample was prepared by high-energy ball mill method. A known quantity of anatase phase- TiO 2 was milled for 83 h in air. The samples were collected at intervals of 5 h of milling. The XRD patterns were recorded for all the samples. The crystal structure changed from anatase phase for bulk material to rutile-rich phase for nanocrystalline material. Nanocrystalline TiO 2, which is a mixture of anatase, rutile, and srilankite phase, was prepared by milling for 60 h. The XRD pattern of unmilled anatase phase of TiO 2 could be refined with I41/amd space group. The crystallite size of the TiO 2 was found to decrease with milling time upto 50 h and then the size of rutile phase increases while the sizes of anatase and srilankite phases remain constant upto 60 h of milling. After 60 h, the sizes of all the phases remain constant. The average crystallite size for rutile phase is found to be 12 nm after 60 h of milling.

Microstructural Transformations of Al2O3-TiO2 and Al2O3-ZrO2 Powders Induced by High-Energy Ball-Milling

2006 ◽  
Vol 45 ◽  
pp. 303-308
Author(s):  
Sandrine Coste ◽  
Ghislaine Bertrand ◽  
Christian Coddet ◽  
Eric Gaffet ◽  
Horst Hahn ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Milling Time ◽  
Tetragonal Zirconia ◽  
Rutile Phase ◽  
High Energy ◽  
Planetary Mill ◽  
Energy Ball ◽  
Yttria Partially Stabilized Zirconia ◽  
Tio2 Phase ◽  
Zro2 System

Superior properties of nanostructured Al2O3 based materials, such as higher hardness and fracture toughness, have been evidenced. In order to optimize their manufacturing, the mechanical activation of the starting powders (Al2O3-TiO2 and Al2O3-ZrO2) was studied. In the present work, Al2O3 powders blended with 13wt% and 44wt% of titania or 20wt% and 80wt% of yttria partially stabilized zirconia have been high-energy ball-milled using a planetary mill, P4 (Fritsch) with steel vials and balls. The effect of the milling time and operating parameters, such as shock energy and friction to total energy ratio, on the powder structural and microstructural evolutions has been determined by SEM, XRD and BET. The transformation of the metastable anatase TiO2 phase into the high pressure TiO2 II phase and rutile phase was evidenced, simultaneously to the decrease of the alumina crystallite size, in the Al2O3-TiO2 system. In the Al2O3-ZrO2 system, the transformation of the monoclinic phase and the decrease of the alumina and tetragonal zirconia crystallite size have been observed.

scholarly journals Characterization of Mechanically Alloyed Nanocrystalline Fe(Al): Crystallite Size and Dislocation Density

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
M. Mhadhbi ◽  
M. Khitouni ◽  
L. Escoda ◽  
J. J. Suñol ◽  
M. Dammak
Keyword(s):  
Solid Solution ◽  
Dislocation Density ◽  
Crystallite Size ◽  
Average Crystallite Size ◽  
High Energy ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
High Energy Ball Mill

A nanostructured disordered Fe(Al) solid solution was obtained from elemental powders of Fe and Al using a high-energy ball mill. The transformations occurring in the material during milling were studied with the use of X-ray diffraction. In addition lattice microstrain, average crystallite size, dislocation density, and the lattice parameter were determined. Scanning electron microscopy (SEM) was employed to examine the morphology of the samples as a function of milling times. Thermal behaviour of the milled powders was examined by differential scanning calorimetry (DSC). The results, as well as dissimilarity between calorimetric curves of the powders after 2 and 20 h of milling, indicated the formation of a nanostructured Fe(Al) solid solution.

scholarly journals Influence of Milling Media on the Mechanical Alloyed W-0.5 wt.% Ti Powder Alloy

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Hadi Jahangiri ◽  
Sultan Sönmez ◽  
M. Lütfi Öveçoğlu
Keyword(s):  
Crystallite Size ◽  
Milling Time ◽  
High Energy ◽  
Lattice Parameter ◽  
Mechanically Alloyed ◽  
High Energy Ball Mill ◽  
Powder Density ◽  
Energy Ball ◽  
Ti Powder ◽  
Milled Powders

The effects of milling atmosphere and mechanical alloying (MA) duration on the effective lattice parameter, crystallite size, lattice strain, and amorphization rate of the W-0.5 wt.% Ti powders were investigated. W-0.5 wt.% Ti powders were mechanically alloyed (MA’d) for 10 h and 20 h in a high energy ball mill. Moreover, morphology of the powders for various MA was analyzed using SEM microscopy. Their powder density was also measured by helium pycnometer. The dry milled agglomerated powders have spherical particle, while wet milled powders have layered morphology. Milling media and increasing of milling time significantly reduce the crystallite size. The smallest crystallite size is 4.93 nm which belonged to the dry milled powders measured by Lorentzian method after 20 hours’ MA. However, after 20 hours, MA’d powders show the biggest crystallite size, as big as 57.07 nm, measured with the same method in ethanol.

scholarly journals Effects of Milling Atmosphere and Increasing Sintering Temperature on the Magnetic Properties of Nanocrystalline Ni0.36Zn0.64Fe2O4

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Abdollah Hajalilou ◽  
Mansor Hashim ◽  
Halimah Mohamed Kamari ◽  
Mohamad Taghi Masoudi
Keyword(s):  
Magnetic Properties ◽  
Sintering Temperature ◽  
Parallel Evolution ◽  
High Energy ◽  
High Energy Ball Mill ◽  
Zn Ferrite ◽  
Crystallite Sizes ◽  
Energy Ball ◽  
Xrd Patterns ◽  
Fesem Micrographs

Nanocrystalline Ni0.36Zn0.64Fe2O4was synthesized by milling a powder mixture of Zn, NiO, and Fe2O3in a high-energy ball mill for 30 h under three different atmospheres of air, argon, and oxygen. After sintering the 30 h milled samples at 500°C, the XRD patterns suggested the formation of a single phase of Ni-Zn ferrite. The XRD results indicated the average crystallite sizes to be 15, 14, and 16 nm, respectively, for the 30 h milled samples in air, argon, and oxygen atmospheres sintered at 500°C. From the FeSEM micrographs, the average grain sizes of the mentioned samples were 83, 75, and 105 nm, respectively, which grew to 284, 243, and 302 nm after sintering to 900°C. A density of all the samples increased while a porosity decreased by elevating sintering temperature. The parallel evolution of changes in magnetic properties, due to microstructural variations with changes in the milling atmosphere and sintering temperature in the rage of 500–900°C with 100°C increments, is also studied in this work.

A Study of Pb (Zr0.52Ti0.48)O3 Ceramic Properties via High Energy Ball Mill

2015 ◽  
Vol 1087 ◽  
pp. 223-226
Author(s):  
Shafiza Afzan Sharif ◽  
J.M. Juliewatty ◽  
W.A.W. Yusoff
Keyword(s):  
Perovskite Phase ◽  
High Energy ◽  
Soaking Time ◽  
Grain Sizes ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Higher Temperature ◽  
Ball Milling Technique ◽  
Xrd Patterns ◽  
The Relationship

Pb (Zr0.52Ti0.48)O3, (PZT) powder has been synthesized using high energy ball milling technique. The synthesized powders were characterized using XRD, SEM, Density, Porosity and Impedance Analyzer. XRD patterns show that the perovskite phase of PZT can be formed from the mixture of starting material after milling for 40 h. The grain sizes of the powder have been estimated to be 1-3 μm. The relationship between the microstructure of the PZT samples and sintering temperature has been discussed. Dense PZT (> 95 % theoretical density) with excellent dielectric properties was obtained when the pellet are sintered at higher temperature with shorter soaking time. The results show that the sample sintered at 1100 °C /1 h yields a clearly uniform grain size with the highest dielectric constant.

EFFECT OF AGING AND CALCINATION ON MORPHOLOGY AND PROPERTIES OF SYNTHESIZED NANOCRYSTALLINE TiO2

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3210-3215 ◽  
Author(s):  
H. ESLAMI NAMIN ◽  
H. HASHEMIPOUR ◽  
M. RANJBAR
Keyword(s):  
Titanium Dioxide Nanoparticles ◽  
Anatase Phase ◽  
Ammonium Hydroxide ◽  
Rutile Phase ◽  
Average Crystalline Size ◽  
X Ray Diffraction ◽  
Nanocrystalline Tio2 ◽  
X Ray ◽  
Titania Gel ◽  
Xrd Patterns

Titanium dioxide nanoparticles were prepared by precipitation of aqueous TiCl 4 solution with ammonium hydroxide as precipitation agent. Freshly prepared Titania gel is allowed to crystallize under refluxing and stirring condition for 6 h over 90°C and oven dried over night in temperature above 100 C. X-ray diffraction studies on oven dried powder indicate formation of anatase phase TiO 2 with average crystalline size of 4.5 nm. Powders with variable amount of anatase and rutile phase were prepared by calcination of pure anatase in the temperature range 400-1000 c for 4 h. the XRD patterns show that phase transition from anatase to rutile occur in calcination above 600°C. The morphology and microstructure characteristics were obtained by XRD, TEM. and TGA.

High-Energy Ball Milling Conditions in Formation of NiTiCu Shape Memory Alloys

2021 ◽  
pp. 1-7
Author(s):  
Tomasz Goryczka ◽  
Piotr Salwa ◽  
Maciej Zubko
Keyword(s):  
Chemical Composition ◽  
Shape Memory ◽  
Crystallite Size ◽  
Ball Milling ◽  
Average Crystallite Size ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Energy Ball ◽  
Average Size ◽  
Grinding Time

The properties and the shape memory effect depend, among other things, on chemical composition, as well as the method of shape memory alloy (SMA) production. One of the manufacturing methods that leads to the amorphous/nanocrystalline SMA is high-energy ball milling combined with annealing. Using this technique, an SMA memory alloy, with the nominal chemical composition of Ni25Ti50Cu25, was produced from commercial elemental powders (purity −99.7%). The structure and morphology were characterized (at the various stages of its production) by the use of X-ray diffraction, as well as electron microscopy (both scanning and transmission). Choosing the appropriate grinding time made it possible to produce an NiTiCu alloy with a different crystallite size. Its average size changed from 6.5 nm (after 50 h) to about 2 nm (100 h). Increasing the grinding time up to 140 h resulted in the formation of areas that showed the B19 martensite and the Ti2(Ni,Cu) phase with the average crystallite size of about 6 nm (as milled). After crystallization, the average size increased to 11 nm.

Structure and Magnetic Properties of Ternary Nanosized FeAlSn and CuFeCo Powders Synthesized by Mechanical Milling

2017 ◽  
Vol 47 ◽  
pp. 79-88 ◽  
Author(s):  
Z. Hamlati ◽  
W. Laslouni ◽  
Mohammed Azzaz ◽  
M. Zergoug ◽  
D. Martínez-Blanco ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Crystallite Size ◽  
Milling Time ◽  
Magnetic Measurements ◽  
High Energy ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
High Energy Ball Mill ◽  
Powder Particles ◽  
Energy Ball

Ternary Fe72Al26Sn2 and Cu70Fe18Co12 alloys were obtained by mechanical alloying of pure Fe, Al, Sn, Cu and Co powders using a high energy ball mill. X-ray diffraction and electron microscopy supported by magnetic measurements have been applied to follow changes in the microstructure, phase composition and magnetic properties in dependence on milling time. With the increase of milling time all Al and Sn atoms dissolved in the bcc Fe and the final product of the MA process was the nanocrystalline Fe (Al, Sn) solid solution in a metastable state with a large amount of defects and mean crystallite size of 5 nm. However, the obtained crystallite size value is about 10 nm for the ball milled Cu70Fe18Co12 powders. The electron microscope observations show the morphology of powder particles. Magnetic properties of the nanocrystalline mechanically alloyed FeAlSn and CuFeCo were also investigated and were related to the microstructural changes.

Structure and Morphology of Sol-Gel Nanocrystalline TiO2 Films Coated on Glass Substrates

2010 ◽  
Vol 434-435 ◽  
pp. 565-567
Author(s):  
G.J. Ji ◽  
Zhi Ming Shi ◽  
G. Zhao
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Rutile Phase ◽  
Dip Coating ◽  
Tio2 Films ◽  
Nanocrystalline Tio2 ◽  
Doped Tio2 ◽  
Glass Substrates ◽  
Dip Coating Technique

The Ce3+-doped and undoped nanocrystalline TiO2 films were prepared on glass substrates surface by sol-gel dip coating technique. The crystal structure and surface morphology of TiO2 films were characterized by means of X-ray diffractometer (XRD), transmission electron microscopy (TEM) and atomic force microscope (AFM). The results indicated that the Ce3+-doped TiO2 films were solely composed of the anatase phase whereas in the undoped films small amount of the rutile phase of TiO2 were present. The average crystallite size of the undoped TiO2 films was about 30nm and was decreased with Ce3+-doping in the TiO2 films. Moreover, the grains distributed more uniform and the surface roughness was smaller in the Ce3+-doped TiO2 films than in the undoped one. The action mechanism of Ce3+-doping inhibits the crystallization of the rutile phase and decreases the anatase granularity of TiO2 films is associated with its physicochemical properties, as well as ionic diffusion and valance change of Ce3+ to Ce4+ in the sintering process.

High Energy Planetary Ball Milling of SiC Powders

2007 ◽  
Vol 351 ◽  
pp. 7-14 ◽  
Author(s):  
Yu Bai Pan ◽  
Zheng Ren Huang ◽  
Dong Liang Jiang ◽  
Léo Mazerolles ◽  
D. Michel ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Ball Milling ◽  
Average Crystallite Size ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Fine Powders ◽  
Sic Ceramics ◽  
Sem And Tem ◽  
Planetary Ball Milling ◽  
Energy Ball

The effects of high-energy ball milling on SiC powders were studied using a planetary apparatus. Conditions to obtain nanostructured SiC powders with an average crystallite size of 4 nm were determined and powders were characterized by XRD, SEM and TEM analyses. This process was applied to prepare fine powders leading to dense SiC ceramics by sintering at 1900oC for 30 minutes under 30 MPa in argon.

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