scholarly journals Fabrication of Single-Phase NiTi by Combustion Synthesis of Mechanically Activated Powders

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
S. Mousavi Nasab ◽  
M. Aboutalebi ◽  
S. H. Seyedein ◽  
A. Molavi Kakhki ◽  
J. Vahdati Khaki
Keyword(s):  
Combustion Synthesis ◽  
Ignition Temperature ◽  
Ball Mill ◽  
Single Phase ◽  
Milling Time ◽  
Time Profile ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Temperature Time

Single-phase NiTi was fabricated through the thermal explosion mode of combustion synthesis of mechanically activated powders. Combustion and ignition temperatures of combustion synthesis were investigated in different milling times. In this process, equiatomic powder mixtures of nickel and titanium were activated by planetary ball mill and pressed into disk-shaped pellets then heated in a tube furnace, while temperature-time profile was recorded. X-ray diffraction analysis (XRD) was performed on milled powders as well as synthesized samples. Scanning electron microscopy (SEM) was also used to study the microstructural evolution during milling. The results showed that there was a threshold milling time to obtain single-phase NiTi. It was also seen that the ignition temperature and combustion temperature were reduced significantly by increasing milling time.

Ball Milling of the β-FeSi2 Phase

2008 ◽  
Vol 587-588 ◽  
pp. 410-414
Author(s):  
Benilde F.O. Costa ◽  
Gerard Le Caër ◽  
M. Ramos Silva
Keyword(s):  
Mössbauer Spectroscopy ◽  
Ball Milling ◽  
Ball Mill ◽  
Milling Time ◽  
Mossbauer Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mößbauer Spectroscopy

A β-FeSi2 sample was ball-milled for different periods in a vibratory ball-mill and studied by X-ray diffraction and Mössbauer spectroscopy. It transforms gradually with milling time into an α-FeSi2 phase.

Synthesis of Ti3Si0.4Al0.8C1.8 Solid Solution

2008 ◽  
Vol 368-372 ◽  
pp. 995-997
Author(s):  
Cui Wei Li ◽  
Hong Xiang Zhai ◽  
Yang Zhou ◽  
Shi Bo Li ◽  
Zhi Li Zhang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
Lattice Parameters ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Scanning Electron

In this study, free Ti/Si/Al/C powder mixtures with molar ratio of 3:0.4:0.8:1.8 were heated in Argon with various schedules, in order to reveal the possibility for the synthesis of Ti3Si0.4Al0.8C1.8 solid solution powder. X-ray diffraction (XRD) was used for the evaluation of phase identities of the powder after different treatments. Scanning electron microscopy (SEM) was used to observe the morphology of the Ti3Si0.4Al0.8C1.8 solid solution. XRD results showed that predominantly single phase samples of Ti3Si0.4Al0.8C1.8 was prepared after heating at 1400oC for 5 min in Argon and the lattice parameters of Ti3Si0.4Al0.8C1.8 lay between those of Ti3SiC2 and Ti3AlC2.

Functionally Graded TiC-Based Cermets via Combustion Synthesis and Quasi-Isostatic Pressing

2005 ◽  
Vol 492-493 ◽  
pp. 63-68 ◽  
Author(s):  
M. Martinez Pacheco ◽  
Marianne Stuivinga ◽  
Eric Carton ◽  
Laurens Katgerman
Keyword(s):  
Combustion Synthesis ◽  
Functionally Graded ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
Powder Mixtures ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Graded Material ◽  
Granulate Medium ◽  
Scanning Electron

Experimental results on the preparation of functionally graded TiC-based cermets obtained by combustion synthesis (also known as Self-Propagating High-Temperature Synthesis, SHS) followed by quasi-isostatic (QIP) pressing in a granulate medium are presented. Pellets of TiC-Fe graded cermets are produced by stacking layers of Ti and C powder mixtures in which the content of a NiFe alloy (50 wt% Ni and 50 wt% Fe) is varied from 5 up to 25 vol %. X-ray diffraction showed that the NiFe alloy did not react with the TiC, thus preserving its special properties. Scanning electron microscopy results show a graded material with pores increasing in size towards the side with the highest ceramic fraction.

The Transformation of Co-Rich Alloys Produced by Mechanical Alloying

2006 ◽  
Vol 509 ◽  
pp. 135-140
Author(s):  
Francisco Cruz-Gandarilla ◽  
R. Gayosso-Armenta ◽  
J. Gerardo Cabañas-Moreno ◽  
Heberto Balmori-Ramírez
Keyword(s):  
Single Phase ◽  
Intermetallic Phase ◽  
High Energy ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Powder Mixtures ◽  
X Ray ◽  
Heat Treated ◽  
Energy Ball

Elemental powder mixtures of Co and Ti were subjected to high-energy ball milling in order to produce mechanically alloyed powders with nominal compositions Co64Ti36, Co67Ti33, Co70Ti30, Co73Ti27, Co76Ti24 and Co85Ti15. The mechanically alloyed powders were treated during 30 minutes in inert atmosphere at temperatures in the range 300 – 700 °C. Both the as-milled powders as well as those subjected to heat treatments have been characterized by x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray spectrometry and differential thermal analysis. As-milled products consist mostly of agglomerated powders with a size between 10 and 80 µm which give an amorphous-like diffraction pattern, except for the Co85Ti15 sample whose pattern presents the characteristic peaks of the Co3Ti intermetallic phase. The transformation of the asmilled powders occurs at temperatures in the range of about 530 – 670 °C with clearly observed exothermic events. The Co3Ti phase is found in all heat treated samples, together with fcc-Co (in Co76Ti24 and Co85Ti15) or the hexagonal Co2Ti intermetallic phase (in Co64Ti36, Co67Ti33 and Co70Ti30); the Co73Ti27 sample was essentially single-phase Co3Ti after heating to 700 °C. Our results suggest the occurrence of crystallization of an amorphous phase in two overlapping stages during heating of the mechanically alloyed powders.

Synthesize Ti3SiC2 from TiH2 by Pressureless Sintering

2012 ◽  
Vol 512-515 ◽  
pp. 676-680 ◽  
Author(s):  
Liang Li ◽  
Ai Guo Zhou ◽  
Li Bo Wang ◽  
Fei Xiang Hu
Keyword(s):  
Electron Microscopy ◽  
Single Phase ◽  
Argon Atmosphere ◽  
Pressureless Sintering ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
Titanium Silicon Carbide ◽  
X Ray ◽  
Titanium Silicon ◽  
Scanning Electron

In this paper, titanium silicon carbide (Ti3SiC2) powders were synthesized from TiH2 as Ti source by pressureless sintering in flowing argon atmosphere without preliminary dehydrogenation. Starting materials are powder mixtures with the mole ratio of 3TiH2/Si/2C or 3TiH2/SiC/C. Both kinds of starting materials were sintered in a tube furnace at the temperature range from 1300°C to 1500°C for 10~180min in flowing argon atmosphere. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the phase compositions and morphology of the products after different treatments. It was showed that almost single phase Ti3SiC2 powder (94.7 wt.%) can be synthesized by pressureless sintering from 3TiH2/Si/2C powders at 1400~1425°C for about 180min or from 3TiH2/SiC/C powders at 1425~1500°C for about 180min. From SEM micrographs, as-synthesized samples were porous. Most plate-like grains were about 5~10 μm in diameter and 1~2 μm in thickness. The speed of temperature increasing is an important factor to affect the purity of as-synthesized Ti3SiC2.

Combustion Synthesis of Cu1-xNixCr2O4 Spinel for Catalytic Applications

2005 ◽  
Vol 498-499 ◽  
pp. 663-668 ◽  
Author(s):  
P.M. Pimentel ◽  
M.F. Ginani ◽  
Antonio Eduardo Martinelli ◽  
D.M.A. Melo ◽  
A.M. Garrido Pedrosa ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Catalytic Combustion ◽  
Fine Particles ◽  
Particle Morphology ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Heterogeneous Processes ◽  
Different Temperatures ◽  
Cost Efficient

Transition-metal spinels are efficient catalysts in a number of heterogeneous processes, such as CO oxidation, catalytic combustion of hydrocarbons and oxychlorination of methane. The properties of catalytic materials are highly dependent on the synthesis route. Spinels are often produced at high temperatures by the calcination of precursors such as powder mixtures, slurries or resins. Combustion synthesis is a cost-efficient method used to produce homogeneous and fine particles with high reproducibility. Cu0.8Ni0.2Cr2O4 spinel was obtained by the combustion of metallic nitrates using urea as fuel. The resulting powders were calcinated at different temperatures and characterized by thermogravimetric and particle size analyses, X ray diffraction, and scanning electron microscopy. The effect of urea on the control of the process and particle morphology was investigated. The results revealed the formation of porous powders with increasing crystallinity as the calcination temperature increased. Crystallization of spinel started at 700 oC.

Synthesis, Characterization and Properties of Forsterite Refractory Produced from Thai Talc and Magnesite

2018 ◽  
Vol 940 ◽  
pp. 46-50
Author(s):  
Surapattanapong Kullatham ◽  
Sakdiphon Thiansem
Keyword(s):  
Physical Properties ◽  
Mechanical Activation ◽  
Ball Mill ◽  
Milling Time ◽  
Raw Materials ◽  
True Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrf Scanning ◽  
Subsequent Calcination

This paper reports the synthesis, characterizations, microstructure and properties of forsterite powder produced in Thailand from talc and magnesite as raw materials by using mechanical activation with subsequent calcination. The synthesis forsterite powder were mixed by using talc and magnesite at 1:5 mole ratio. The maximum milling time was 24 h in a planetary zirconia ball mill. Afterward, the mixtures were calcined in an electric furnace for 1 h at 900, 1000, 1100, 1200 and 1300°C respectively. The synthesized powder was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and physical properties. Results of the physical properties of synthesized forsterite showed an increased in density as the calcining temperature increased. In contrast, porosity was decreased with an increase of the calcining temperature. Therefore, forsterite that was calcined at 1300°C provided the best results which were 2.96 g/cm3 of true density and 15.41% of true porosity. Results of XRD of synthesized powder indicated that the forsterite crystallization was constant for which sharpen appeared after 5 h of mechanical activation. Fraction of forsterite was appeared after being calcined at 1000°C for 1 h with an increasing of calcination temperature, the fraction of forsterite phase increased. Based on the mentioned characteristics, the forsterite produced from Thai talc and magnesite exhibited properties of an insulator and can potentially be used as refractory devices.

scholarly journals EFFECT OF ANNEALING ON MAGNETIC AND STRUCTURAL PROPERTIES OF THE NANOCRYSTALLINE Fe-Mn-Al ALLOYS

2016 ◽  
Vol 2 (1) ◽  
pp. 26
Author(s):  
K. Tarigan ◽  
D. Sebayang
Keyword(s):  
Single Phase ◽  
Milling Time ◽  
Al Alloys ◽  
Magnetic Saturation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Vibration Sample Magnetometer ◽  
X Ray Absorption ◽  
Scanning Electron

<p>In this work, the formations of Fe<sub>55</sub>Mn<sub>10</sub>Al<sub>35</sub> nanocrystalline alloys were made by using mechanical alloying (MA) technique with the milling time of 24 hrs and then annealed at 300, 500, and 700<sup>o</sup>C. The sizes and the morphology of the particles were checked by using a Scanning Electron Microscope (SEM). The magnetic properties were characterized by using a Vibration Sample Magnetometer (VSM), and it give results both of the magnetic saturation (<em>Ms</em>) and Coercivity (<em>Hc</em>) are decreased respect to annealing temperatures. Last one; the structures were characterized by using an Extended X-ray Absorption Fine Structure (EXAFS) and X-Ray Diffraction (XRD). It give results that the structures were single phase at 24 hrs milled and 300<sup>o</sup>C annealed, then the structure to be changed at 500 and 700<sup>o</sup>C. </p>

scholarly journals Microstructure and chemistry of MgO- and CoO-doped nickel-titanate spinels

1994 ◽  
Vol 52 ◽  
pp. 1002-1003
Author(s):  
I. M. Anderson ◽  
C. B. Carter ◽  
J. Bentley
Keyword(s):  
Single Phase ◽  
Spinel Phase ◽  
X Ray Diffraction ◽  
Uniform Size ◽  
Powder Mixtures ◽  
X Ray ◽  
Nickel Titanate ◽  
Diffraction Patterns ◽  
Faceted Particles ◽  
Single Set

When NiO-rich powder mixtures of NiO and TiO2 are equilibrated in air above ∼1425°C and subsequently quenched, X-ray diffraction patterns of the resulting specimens can be indexed with a single set of reflections in the Fd3m space group. Originally this result was cited as evidence of a highly nonstoichiometric single phase. However, subsequent TEM investigations showed that these specimens are composed of periclase- and spinelstructured phases with small domains and coherent phase boundaries. Periclase-structured domains are distributed throughout the spinel with two distinct morphologies: cuboidal particles, faceted on {100}, of uniform size that increases from 30 to 150 run with increasing NiO-mole-fraction; and an isotropic interconnected twophase microstructure, also of uniform size, varying from 2 to 5 ran seemingly independent of composition. The finer-scale features strongly resemble those arising from spinodal decomposition in an isotropic medium and can be ascribed to decomposition of a nonstoichiometric spinel phase during quenching. It has recently been suggested that the faceted particles coexist with the nonstoichiometric spinel at the equilibration temperature.

MECHANOCHEMICAL SYNTHESIS OF SINGLE PHASE NANOCRYSTALLINE FORSTERITE POWDER

2010 ◽  
Vol 24 (03) ◽  
pp. 343-350 ◽  
Author(s):  
F. TAVANGARIAN ◽  
R. EMADI
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanochemical Synthesis ◽  
Ball Mill ◽  
Single Phase ◽  
Magnesium Carbonate ◽  
Subsequent Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Pure nanocrystalline forsterite ( Mg 2 SiO 4) powder was successfully synthesized by mechanochemical route and subsequent annealing. The starting materials were talc ( Mg 3 Si 4 O 10( OH )2) and magnesium carbonate ( MgCO 3) powders. To produce forsterite powder, first talc and magnesium carbonate powders were calcined at 1200°C for 1 h and 700°C for 2 h, respectively. After that the mixture of obtained powders was milled by a planetary ball mill, and then annealed at 1000°C and 1200°C for 1 h. Thermogravimetric (TG) analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques were utilized to characterize the initial and prepared powders. The results showed that a single phase nanocrystalline forsterite powder with a crystallite size of 49 nm was obtained after 40 h milling and subsequent annealing at 1000°C for 1 h.

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