Hydrogen and its effect on the grinding of Ti-Ni powder

2021 ◽  
Vol 23 (3) ◽  
pp. 100-111
Author(s):  
Ekaterina Abdulmenova ◽  
◽  
Sergey Kulkov ◽  
Keyword(s):  
Particle Size ◽  
Dislocation Density ◽  
High Intensity ◽  
Ball Mill ◽  
Mechanical Treatment ◽  
Average Particle Size ◽  
Lattice Parameter ◽  
Planetary Ball Mill ◽  
Average Particle ◽  
X Ray

Introduction. Industrial nickel-titanium alloy PN55T45 closed to the equiatomic composition is widely used for the manufacture of products by powder metallurgy. To achieve high physical and mechanical properties of the material obtained by this method, it is necessary to use fine powders, which can be obtained by implementing high-intensity grinding in a planetary ball mill. However, during such treatment, contamination, powder oxidation and particle aggregation, etc. are possible. To solve this problem, preliminary hydrogenation is proposed for subsequent grinding in a planetary ball mill. The aim of the work is to study the effect of hydrogen on the grinding of titanium nickelide powder. Materials and methods. The morphology and average particle size of the powders were studied by scanning electron microscopy. The structure and phase composition of the powders were investigated by the methods of X-ray structural and X-ray phase analysis. The data of X-ray structural analysis were used to estimate the dislocation density. Results and discussions. It is shown that the use of pre-hydrogenation for 180 minutes before machining allows reducing the average particle size by about a half. After mechanical treatment of the powder, the parameters of the crystal lattices of the TiNi (austenite), Ti2Ni and Ni3Ti phases do not change within the error range. After mechanical treatment of the powder with preliminary hydrogenation, the crystal lattice parameter of only the Ti2Ni phase changes significantly, in particular, at 180 minutes of hydrogenation, the lattice parameter increases to 1.1457 ± 5×10-4 nm, which corresponds to the stoichiometry of the Ti2NiH0.5 hydride with a lattice parameter of 1.1500 nm. The highest dislocation density estimated by X-ray diffraction analysis is contained in the Ti2Ni (511) phase than in the TiNi (austenite) (110) and Ni3Ti (202) phases. Thus, preliminary hydrogenation can be an effective method of powder grinding due to the formation of brittle hydride and suppression of the aggregation of fine particles during high-intensity mechanical treatment.

scholarly journals Thermal, Structural, and Physical Properties of Freeze Dried Tropical Fruit Powder

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Athmaselvi ◽  
C. Kumar ◽  
M. Balasubramanian ◽  
Ishita Roy
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Tropical Fruit ◽  
X Ray ◽  
Freeze Dried ◽  
Fruit Powder ◽  
Lcr Meter

This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya) fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.

scholarly journals Preparation of ultrafine iron phosphate micro-powder from phosphate slag

2018 ◽  
Vol 238 ◽  
pp. 02002
Author(s):  
Fangjing Sun ◽  
Yi Zhang ◽  
Jiawei Zhang ◽  
Xixi Yan ◽  
Xiaoyu Liu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Electron Microscope ◽  
Average Particle Size ◽  
Iron Phosphate ◽  
Average Particle ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Phosphate Slag ◽  
Scanning Electron

In this experiment, ultrafine iron phosphate micro-powder was prepared by hydrothermal method which used phosphate slag as an iron source. The effects of reaction temperature, surfactants type and amount on its particle size were explored. The samples were characterized by using Malvern Laser Particle Size Analyzer (MS2000), X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX).The results showed that at 160 °C, 1 wt%CTAB, monoclinic iron phosphate micro-powder was obtained with an average particle size about 0.4 μm which also has a good dispersion in aqueous solution.

Morphology-Controlled CaCO3 Nanostructures by Modified Co-Precipitation in Pulsed Mode

2015 ◽  
Vol 752-753 ◽  
pp. 148-153
Author(s):  
M.M. Nassar ◽  
Taha Ebrahiem Farrag ◽  
M.S. Mahmoud ◽  
Sayed Abdelmonem
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Rotation Speed ◽  
Average Particle Size ◽  
Calcium Nitrate ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray ◽  
Co Precipitation ◽  
Pulsed Mixing

Calcium carbonate nanoparticles and nanorods were synthesized by precipitation from saturated sodium carbonate and calcium nitrate aqueous solutions through co precipitation method. A new rout of synthesis was done by both using pulsed mixing method and controlling the addition of calcium nitrate. The effect of the agitation speed, and the temperature on particle size and morphology were investigated. Particles were characterized using X-ray Microanalysis, X-ray analysis (XRD) and scanning electron microscopy (SEM). The results indicated that increasing the mixer rotation speed from 3425 to 15900 (rpm) decreases the average particle size to 64±7 nm. A rapid nucleation then aggregation induced by excessive shear force phenomena could explain this observation. Moreover, by increasing the reaction temperature, the products were converted from nanoparticle to nanorods. The maximum attainable aspect ratio was 6.23 at temperature of 75°C and rotation speed of 3425. Generally, temperature raise promoted a significant homoepitaxial growth in one direction toward the formation of calcite nanorods. Overall, this study can open new avenues to control the morphology of the calcium carbonate nanostructures.

Fabrication and Characterization of Nanospinel ZnCr2O4 Using Thermal Treatement Method

2015 ◽  
Vol 1107 ◽  
pp. 301-307 ◽  
Author(s):  
Salahudeen A. Gene ◽  
Elias B. Saion ◽  
Abdul Halim Shaari ◽  
Mazliana A. Kamarudeen ◽  
Naif Mohammed Al-Hada
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Average Particle Size ◽  
Treatment Method ◽  
Esr Spectra ◽  
Resonance Spectroscopy ◽  
Average Particle ◽  
Face Centered Cubic ◽  
X Ray ◽  
Xrd Patterns

The fabrication of nanospinel zinc chromite (ZnCr2O4) crystals by the means of thermal treatment method from an aqueous solution containing metal nitrates, polyvinyl pyrrolidone (PVP), and deionized water was described in this study. The samples were calcined at various temperatures ranging from 773 to 973 K for the decomposition of the organic compounds and crystallization of the nanocrystals. PVP was used as capping agent to control the agglomeration of the particles. The characterization studies of the fabricated samples were carried out by X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), energy dispersed X-ray spectroscopy (EDX) and electron spin resonance spectroscopy (ESR). The corresponding peaks of Zn, Cr and O were observed in the EDX spectrum of the sample which confirms the formation of ZnCr2O4. The XRD patterns also confirmed the formation of the single faced nanocrystallines of spinel ZnCr2O4 with a face-centered cubic structure. The average particle size of the synthesized crystals was also determined from the XRD patterns using the Scherers formula which shows that the crystallite sizes increases with increase in calcination temperature and was in good agreement with the TEM images which shows cubical ZnCr2O4 nanocrystals with uniform morphology and particle size distributions. The ESR spectra confirmed the existence of unpaired electron in the fabricated samples and the increase in g-factor and decreases in resonant magnetic field (Hr) were observed as the calcination temperature increases.

Kinetic study and modeling of the solid-state reaction Y2BaCuO5 + 3BaCuO2 + 2CuO ⇉ 2YBa2Cu3O6.5−x + xO2

1990 ◽  
Vol 5 (10) ◽  
pp. 2056-2065 ◽  
Author(s):  
Nae-Lih Wu ◽  
Ta-Chin Wei ◽  
Shau-Y Hou ◽  
S-Yen Wong
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Solid State Reaction ◽  
Size Dependence ◽  
Average Particle Size ◽  
Average Particle ◽  
Fractional Conversion ◽  
X Ray ◽  
Unreacted Core ◽  
Kinetics Of

The kinetics of the solid-state reaction Y2BaCuO5 + 3BaCuO2 + 2CuO ⇉ 2YBa2Cu3O6.5−x + xO2 was studied by using x-ray diffractometric and thermogravimetric analyses. Both analyses established that the reaction was well described by the kinetic equation: 1 − 3(1 − F)2/3 + 2(1 − F) = k0 exp(− E/RT)t, where F is the fractional conversion of a calcined powder, E is 520 kcal/molc and, for a rcactant mixture with an average particle size of 3 μm, k0 is 2.03 ⊠ 1092 min−1. An unreacted-core shrinking model was proposed to obtain the particle-size dependence of the reaction, and predicted that the pre-exponential constant k0 changed with reactant particle size by k0 = 2.03 ⊠ 1092(3/d)2 exp(4/d − 4/3), where d is the average reactant particle size in μm.

Process Parameters Optimization of Direct Synthesis Nano Magnesium Fluoride Powders

2012 ◽  
Vol 184-185 ◽  
pp. 1146-1149
Author(s):  
Ping Li ◽  
Hai Yang Wang ◽  
Wan E Wu ◽  
Shuai Ling
Keyword(s):  
Particle Size ◽  
Orthogonal Experiment ◽  
Direct Synthesis ◽  
Average Particle Size ◽  
Parameters Optimization ◽  
Magnesium Fluoride ◽  
Process Conditions ◽  
Average Particle ◽  
X Ray ◽  
Mgcl2 Concentration

To reduce average particle size，magnesium fluoride was directly synthesized from MgF2 and NH4F，the product was characterized by X-ray diffractomer，scanning electron microscopy. Orthogonal experiment was used to explore the influences of factors on the average particle size. Found that the effect order of factors on the average particle size is MgCl2 concentration，NH4F concentration，reaction temperature，reaction time，in the optimization of process conditions，average particle size is 23.1 nm.

Analysis of the Promoter-Catalyst interaction between Mn and Rh by Transmission Electron Microscopy

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
B. Graham ◽  
R.F. Klie
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Average Particle Size ◽  
Lattice Parameter ◽  
Average Particle ◽  
Fischer Tropsch ◽  
Transmission Electron ◽  
Three Samples ◽  
Promoter Interaction

In the hope of optimizing the Fischer-Tropsch mechanism to produce cleaner ethanol, the catalyst- promoter interaction between rhodium and manganese was examined by transmission electron microscopy. Three samples were analyzed on a carbon nanotube (CNT) substrate with 3 wt% rhodium (3%Rh/CNT), 1% manganese with 3 wt% rhodium (1%Mn/3% Rh/CNT), and 2% manganese with 3 wt% rhodium (2% Mn/3% Rh/CNT). The average particle size were found to be (1.9 ± 0.6) nm, (2.1 ± 0.5) nm, and (3.2 ± 0.6) nm, respectively. An increase in particle size indicates that the rhodium and manganese are interacting. The lattice parameter for rhodium were also determined to be (4.1 ± 0.1) Å, (4.2 ± 0.1) Å, and (3.8 ± 0.1) Å, respectively. The decrease in lattice parameter in the 2%Mn/3%Rh/CNT sample was most likely due to a change in the crystal structure of the rhodium particles as a result of the interaction between the manganese and rhodium.

Effect of Grinding Methods on the Performance of Ground Fly Ash

2011 ◽  
Vol 477 ◽  
pp. 10-15
Author(s):  
Zhong Yuan Lu ◽  
Xun Xu ◽  
Jun Li
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Ball Mill ◽  
Average Particle Size ◽  
Average Particle ◽  
Uniformity Coefficient ◽  
Mortar Strength ◽  
Particle Size Analyzer ◽  
Vibration Mill ◽  
Scanning Electron

In this study, coarse fly ash was ground with laboratory ball mill, vibration mill and jet mill respectively. The powder characteristic of ground fly ash was tested by laser particle size analyzer and scanning electron microscope. And the performance of cement containing different ground fly ash was also studied. It was observed that the characteristic value of fly ash ground by ball mill, vibration mill and jet mill was 13.543 μm, 13.403 μm and 17.344 μm, respectively, when average particle size was about 25μm. And the uniformity coefficient of fly ash ground by ball mill, vibration mill, and jet mill was 1.26, 1.24 and 1.38, respectively. Specially, the mortar strength was increased when 10 to 20 percent of ground fly ash was added. And the highest fluidity of mortar was obtained when 30 percent of fly ash ground by jet mill was added.

Structural, Optical and Magnetic Properties of Ni Doped ZnS Nanoparticles

2018 ◽  
Vol 24 (8) ◽  
pp. 5640-5644
Author(s):  
B Sreenivasulu ◽  
S. Venkatramana Reddy ◽  
P. Venkateswara Reddy
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Absorption Spectra ◽  
Spherical Surface ◽  
Room Temperature Ferromagnetism ◽  
Average Particle Size ◽  
Precipitation Method ◽  
Chemical Compositions ◽  
Average Particle ◽  
X Ray

Pure ZnS and 3 mol% of Ni doped ZnS nano powders are prepared by chemical co-precipitation method. Properties of ZnS: Ni2+ nanoparticles are studied by X-ray diffraction Spectra (XRD), Raman spectroscopy (RS), Photoluminescence (PL), Absorption Spectra, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDAX), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM). From XRD data, it conform the structure of ZnS, and particle size of pure and Ni doped ZnS data indicates the incorporation of Ni2+ in ZnS nanocrystal lattice. Raman spectra for pure and Ni doped samples exhibited vibrational modes confirm the structure of ZnS. Photoluminescence spectra reveal that the emission peaks are in UV and visible regions; this is confirming the absorption spectra. SEM micrographs show spherical morphology, and chemical compositions of samples are in stoichiometric proportions. TEM micro graphs show the spherical surface morphology and average particle size for pure and Ni2+ doped nanoparticles are in the range of 2–3 nm, this is good agreement with XRD results. M–H curves from VSM show room temperature ferromagnetism.

scholarly journals Synthesis of rare-earth nanosized phosphors using microwave processing

2021 ◽  
Vol 2056 (1) ◽  
pp. 012049
Author(s):  
A B Vlasenko ◽  
V V Bakhmetyev
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Visible Light ◽  
Average Particle Size ◽  
Microwave Treatment ◽  
Viral Diseases ◽  
Medical Applications ◽  
Average Particle ◽  
Light Spectrum ◽  
X Ray

Abstract Nanomaterials find permanently extending applications in various areas of life. In particular, nanosized phosphors can be used as pharmaceutical carriers capable of emitting ultraviolet or visible light that activates a photosensitizer, thus significantly expanding the possibilities of photodynamic therapy in the treatment of oncological, bacterial and viral diseases. The conditions required for the use of nanosized phosphors in medicine include their fine dispersion and effective luminescence in the red region of visible light spectrum upon stimulation by X-ray radiation of the range accepted for medical applications, particularly for diagnostic and therapeutic purposes in many diseases. The aim of this work was to study the effect of microwave treatment of Y2O3:Eu phosphors prepared by hydrothermal synthesis in ethylene glycol at 230 °C for 6 hours, involving the decomposition of mixed acetate. In order to reduce the aggregation and growth of the resulting particles, Aerosil A300 with average particle size 7 nm was added to the reaction mixture in the course of hydrothermal synthesis in the ratio 1:1 relating to the obtained phosphor. The microwave treatment was carried out at 800 °C for 5 minutes. The developed method provided Y2O3:Eu phosphor samples featuring with increased luminescence intensity in the region 610…700 nm compared to similar phosphors earlier prepared using the rapid thermal annealing (RTA) procedure.

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