Mechanochemical Carboaluminothermic Reduction of V2O5 to Produce VC-Al2O3 Nanocomposite

2012 ◽  
Vol 59 (2) ◽  
Author(s):  
Mohsen Hossein-Zadeh ◽  
Fatemeh Tebyani ◽  
Javad Yazdani Cherati ◽  
Omid Mirzaee
Keyword(s):  
Crystallite Size ◽  
Morphological Evolution ◽  
Xrd Analysis ◽  
Lattice Parameter ◽  
Milling Process ◽  
Xrd Study ◽  
Heat Treated ◽  
Nanocomposite Powders

The aim of this investigation is to produce VC–Al2O3 nanocomposite by reducing V2O5 with Aluminum and black carbon powders via mechanochemical process. The effect of milling time on this process was investigated. Milling process was done powder mixture at a rotation speed of 250 rpm for different times. Results showed that VCx has been synthesized after 1 hour of milling. The characterization of phase formation, crystallite size, strain percentage and lattice parameter was done by XRD analysis. To study the morphological evolution and determination of particle size of nanocomposite powders, Field Emission Scanning Electron Microscope (FESEM) was used. The crystallite size and lattice strain were determined by Williamson-Hall method. XRD study showed that for 6 h milling, the width of V4C3 peaks increased while the crystallite size of these phases decreased to about 27nm. In order to formVC–Al2O3 nanocomposite, the mixture was heat treated with the aid of microwave oven. The composite revealed good microwave absorption and heated up to 1150°C.

Characterization of carbides in M50NiL

1991 ◽  
Vol 49 ◽  
pp. 606-607
Author(s):  
L. S. Lin ◽  
K. P. Gumz ◽  
A. V. Karg ◽  
C. C. Law
Keyword(s):  
Temperature Effects ◽  
Base Composition ◽  
Lattice Parameter ◽  
Control Surface ◽  
Carbide Formation ◽  
Particle Sizes ◽  
Low Carbon ◽  
Fee Structure ◽  
Heat Treated

Carbon and temperature effects on carbide formation in the carburized zone of M50NiL are of great importance because they can be used to control surface properties of bearings. A series of homogeneous alloys (with M50NiL as base composition) containing various levels of carbon in the range of 0.15% to 1.5% (in wt.%) and heat treated at temperatures between 650°C to 1100°C were selected for characterizations. Eleven samples were chosen for carbide characterization and chemical analysis and their identifications are listed in Table 1.Five different carbides consisting of M6C, M2C, M7C3 and M23C6 were found in all eleven samples examined as shown in Table 1. M6C carbides (with least carbon) were found to be the major carbide in low carbon alloys (<0.3% C) and their amounts decreased as the carbon content increased. In sample C (0.3% C), most particles (95%) encountered were M6C carbide with a particle sizes range between 0.05 to 0.25 um. The M6C carbide are enriched in both Mo and Fe and have a fee structure with lattice parameter a=1.105 nm (Figure 1).

SYNTHESIS AND CHARACTERIZATION OF NANOCRYSTALLINE FeNi AND Ni3Fe ALLOYS

2011 ◽  
Vol 25 (07) ◽  
pp. 1013-1019 ◽  
Author(s):  
S. AZADEHRANJBAR ◽  
F. KARIMZADEH ◽  
M. H. ENAYATI
Keyword(s):  
Ball Mill ◽  
Morphological Evolution ◽  
Lattice Parameter ◽  
Internal Stresses ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Fe Alloys

Nanocrystalline FeNi and Ni 3 Fe alloys were prepared by mechanical alloying of Fe and Ni elemental powders using a planetary ball mill under protection atmosphere. X-ray diffraction measurements were performed to follow alloy formation process in these alloys. A heat treatment of 1 h at 800°C was carried out to relax the internal stresses of the milled samples. Morphological evolution of powder particles was revealed by scanning electron microscopy. The value of lattice parameter was reached to 0.35762 nm and the hardness was found to be 686 HV at 30 h milled FeNi powder. In the case of Ni 3 Fe the values of 0.3554 nm and 720 HV were obtained for lattice parameter and hardness, respectively.

Low Temperature Synthesis and Characterization of CaO and MgO- Stabilized Nanocrystalline Tetragonal Zirconia by Citrate Gel Process

2008 ◽  
Vol 368-372 ◽  
pp. 754-757
Author(s):  
Hasan Gocmez ◽  
Hirotaka Fujimori
Keyword(s):  
Single Phase ◽  
Tetragonal Zirconia ◽  
Xrd Analysis ◽  
Complex Method ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Heat Treated ◽  
Crystallite Sizes ◽  
Citrate Gel Process

The citrate gel method, similar to the polymerized complex method, was used to synthesize homogenous tetragonal zirconia at 800oC and 1000oC. Nanocrystalline tetragonal single phase has been fully stabilized with 3, 7, 10 mol% CaO and 10, 15 mol% MgO at 800oC, respectively. In addition, the XRD analysis showed the absence of monoclinic phase after addition of 7 and 10 mol% CaO into zirconia-based solid solutions, which have been fully stabilized both 800oC and 1000oC. The crystallite sizes of the t-ZrO2 with 3, 7 and 10 mol% CaO at 1000oC were 32, 28 and 29nm, respectively. For ZrO2- x mol% MgO (x=3, 10, 15) solid solution, the crystallite sizes of samples at 800oC were less than 29nm, however it was increased up to 69nm at 1000oC. The prepared gel and subsequent heat-treated powders were characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM) to get detail information regarding to differentiation of polymorphs of zirconia as well as formation of powders.

Microstructural Characterization of Activated Carbon Obtained from Waste Tires

2014 ◽  
Vol 87 ◽  
pp. 79-84
Author(s):  
Francesca Mazzanti ◽  
Giuseppe Magnani ◽  
Selene Grilli ◽  
Aldo Brillante ◽  
Tommaso Salzillo ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Activated Carbon ◽  
Crystallite Size ◽  
Microstructural Characterization ◽  
Xrd Analysis ◽  
Waste Tires ◽  
Graphitic Structure ◽  
Project Life ◽  
Characterization Of Activated Carbon

SOREME project (LIFE 11 ENV/IT/109) is aimed at synthesizing an innovative sorbent based on activated carbon obtained from the carbonization of waste tires. Microstructural characterization was mainly performed in order to define crystallinity, morphology and porosity of the activated carbon powders obtained in different conditions. In particular, XRD analysis always revealed a partially crystalline structure with different crystallite size of the nanographitic structure. The disorder of these structures was determined by Raman spectroscopy. This evaluation was made on the basis of the ratio of the integrated area of the D and G bands typical of the graphitic structure. Finally, SEM was used to put in evidence the mesopores and macropores.

scholarly journals Pembuatan dan Karakterisasi Bioplastik Berbahan Dasar Biomassa dengan Plasticizer Gliserol

Jurnal MIPA ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 23
Author(s):  
Engellita Maneking ◽  
Hanny Frans Sangian ◽  
Seni Herlina Juita Tongkukut
Keyword(s):  
Acetic Acid ◽  
Xrd Analysis ◽  
Cassava Starch ◽  
Glycerol Water ◽  
The Second Variation ◽  
High Degree ◽  
Tga And Dsc ◽  
Degree Of Degradation

Penelitian ini bertujuan untuk membuat dan mengkarakterisasi bioplastik yang memanfaatkan biomassa singkong. Pembuatan bioplastik dilakukan dengan dua variasi campuran yaitu pati singkong sebagai bahan dasar, gliserol + air sebagai plasticizer, asam asetat (cuka) sebagai katalis dan variasi kedua dengan kombinasi yang sama dengan penambahan alkohol sebagai pembanding. Karakterisasi bioplastik meliputi pengamatan permukaan menggunakan SEM; kristalinitas menggunakan XRD; penentuan gugus fungsi menggunakan FTIR; serta menganalisis sifat termal menggunakan TGA dan DSC. Hasil karakterisasi menunjukkan bahwa bioplastik dengan kombinasi pati singkong+ gliserol + air + asam asetat (cuka) + alkohol mempunyai tingkat degradasi yang tinggi. Hal ini sesuai dengan analisis XRD dimana kombinasi ini memiliki nilai kristalinitas rendah. Hasil spektra IR menunjukkan adanya gugus C-H Alkana, C=O ester, dan C-H Alkena. Sementara hasil SEM memperlihatkan permukaan yang rata dan hasil analisis TGA/DSC yang memperlihatkan pengurangan massa sebesar 2,3234 mgThis study aims to create and characterize bioplastics that utilize cassava biomass. The making of bioplastics is carried out for two variations of mixture, namely cassava starch as the material-based, glycerol + water as plasticizer, acetic acid (vinegar) as a catalyst and the second variation with the same combination with the addition of alcohol as a comparison. Characterization of bioplastics includes surface observations using SEM; crystallinity using XRD; determination of functional groups using FTIR; and analyzing of thermal properties using TGA and DSC. The characterization results show that bioplastics with a combination of cassava starch + glycerol + water + acetic acid (vinegar) + alcohol have a high degree of degradation. This is in accordance with the XRD analysis where this combination has a low crystallinity value. IR spectra showed that the presence of C-H Alkana groups, C = O esters, and C-H alkenes. While the SEM results showed a flat surface and the results of the TGA / DSC analysis which showed a mass reduction of 2.3234 mg.This study aims to create and characterize bioplastics that utilize cassava biomass. The making of bioplastics is carried out for two variations of mixture, namely cassava starch as the material-based, glycerol + water as plasticizer, acetic acid (vinegar) as a catalyst and the second variation with the same combination with the addition of alcohol as a comparison. Characterization of bioplastics includes surface observations using SEM; crystallinity using XRD; determination of functional groups using FTIR; and analyzing of thermal properties using TGA and DSC. The characterization results show that bioplastics with a combination of cassava starch + glycerol + water + acetic acid (vinegar) + alcohol have a high degree of degradation. This is in accordance with the XRD analysis where this combination has a low crystallinity value. IR spectra showed that the presence of C-H Alkana groups, C = O esters, and C-H alkenes. While the SEM results showed a flat surface and the results of the TGA / DSC analysis which showed a mass reduction of 2.3234 mg.

scholarly journals Characterization of the zeolitic tuff from the “Igros-Vidojevici” deposit regarding geological and technological aspects

2018 ◽  
Vol 72 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Vladan Kasic ◽  
Slavica Mihajlovic ◽  
Dragana Zivotic ◽  
Vladimir Simic ◽  
Jovica Stojanovic ◽  
...  
Keyword(s):  
Clay Fraction ◽  
Xrd Analysis ◽  
Blue Dye ◽  
Composition Analysis ◽  
Magnetic Impurities ◽  
Zeolitic Tuff ◽  
Significant Difference ◽  
Central Deposit

This study presents investigations of zeolitic tuff samples from the ?Igros- -Vidojevici? deposit. The aim of the research was to determine the quality of samples taken from all deposit parts. Thus, samples were taken from the footwall (?Zeolit 1?), and four samples from the central deposit part (?Zeolit 2?, ?Zeolit 3?, ?Zeolit 4? and ?Zeolit 5?). Characterization of the samples included chemical analysis, determination of the adsorption coefficient for methylene blue dye and cation-exchange capacity (CEC), X-ray powder diffraction analysis (XRPD), differential thermal and thermogravimetric analysis (DTA and TGA), and Fourier transform Infrared spectroscopic analysis (FTIR). Results have shown that the footwall consists mostly of clays, whereas zeolite minerals dominate in the rest of the deposit. XRD analysis of the ?Zeolit 1? sample confirmed presence of smectite and kaolinite clays, while zeolite of analcime type and quartz are present as smaller fractions. Chemical composition analysis and determination of heavy metal contents showed a significant amount (7.58%) of Fe2O3 in this sample. Therefore, further research can be pursued to find a method for removal of magnetic impurities in this deposit portion in order to utilize the clay fraction. On the other hand, according to XRD, FTIR, DTA/TGA and SEM/EDS analyses, samples which belong to the central deposit part (?Zeolit 2?5?) consist of clinoptilolite zeolite type, while clays are present in less than 10%. Thus, clays (smectites and kaolinite) accompanied with analcime and quartz are the most abundant footwall minerals while central deposit parts contain predominantly clinoptilolite accompanied with small amounts of clays. Mineragenetically, zeolites are most abundant in the ?Zeolit 2? and ?Zeolit 3? samples. The smallest value of CEC was determined for the ?Zeolit 1? sample (46.98 mmol/100g). According to CEC values determined for ?Zeolit 2? and ?Zeolit 3? (141.99 and 121.01 mmol/100 g, respectively) these samples are of the best quality, and could be utilized as adsorbents of inorganic pollutants from contaminated waters. Moreover, they could be potentially used for removal of mycotoxins from cattle feed. ?Zeolit 4? and ?Zeolit 5? samples have shown slightly lower CEC values (89.48 and 83.75 mmol/100 g, respectively), which implies lower quality, and, therefore, could be used for soil quality improvement. Finally, determination of the external CEC has revealed a significant difference between ?Zeolit 1? and ?Zeolit 5? samples (17.9 and 5.31 mmol/100 g, respectively).

Derivation of d-Values from Digitized X-ray and Synchrotron Diffraction Data

1989 ◽  
Vol 33 ◽  
pp. 295-303 ◽  
Author(s):  
T. C. Huang ◽  
W. Parrish ◽  
N. Masciocchi ◽  
P. W. Wang
Keyword(s):  
Diffraction Data ◽  
Practical Method ◽  
Xrd Analysis ◽  
Lattice Parameter ◽  
Lattice Parameters ◽  
Synchrotron Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
D Values

AbstractA precise and practical method for the determination of d-values and lattice parameters from digital diffraction data is described. Systematic errors are corrected mathematically during a d-spacing / lattice-parameter least-Squares refincment process making it unnecessary to use internal standards. X-ray and synchrotron diffraction data of an ICDD alumina plate obtained with a wide variety of experimental conditions and analysis parameters were used to study the precision in the derivation of d-values and the accuracy in the determination of lattice parameters. Results showed that the precision in determining d-values was high with |Δd/d|avg ranging from 2x105 to 4x10-5. Using the results obtained from the high precision XRD analysis as a reference standard, the accuracy in the lattice parameter determinations from the synchrotron diffraction data reached the l-2x10-6] range. Lattice parameters, with an accuracy in the high 10-5 range, were also obtained using parameters commonly used in a routine XRD analysis such as a wide RS (0.11°) for high intensity, peaks only in the front reflection region, no Kα2 stripping, and a Single 2θo parameter for systematic error corrections.

XRD and Tem Characterization of Cathodic MnO2 and Discharge Products in the Li-MnO2 Cell

1995 ◽  
Vol 393 ◽  
Author(s):  
Y. Shao ◽  
S.A. Hackney ◽  
B.C. Cornilsen
Keyword(s):  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Electrolytic Manganese Dioxide ◽  
Cathodic Material ◽  
X Ray ◽  
Heat Treated ◽  
Electrolytic Manganese ◽  
Xrd Patterns ◽  
Convergent Beam

ABSTRACTThe crystal structures of the undischarged, heat-treated electrolytic manganese dioxide (HEMD) and discharge products are characterized by high spatial resolution convergent beam electron diffraction (CBED). The results are compared with the x-ray diffraction (XRD) patterns characterized by broad, diffuse peaks. The CBED results for HEMD show that the starting cathodic material has the pyrolusite space group, but with a range of c/a ratios. The variability of the lattice parameter from grain to grain is found to coincide with the broadening on the low angle side of the XRD peaks. The CBED patterns of discharge products suggest a reduction range in c/a ratios and the formation of another phase.

scholarly journals Characterization of polyparaphenylene (PPP)-based carbons

1996 ◽  
Vol 11 (12) ◽  
pp. 3099-3109 ◽  
Author(s):  
M. J. Matthews ◽  
M. S. Dresselhaus ◽  
M. Endo ◽  
Y. Sasabe ◽  
T. Takahashi ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Electrical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Secondary Battery ◽  
Heat Treated ◽  
Raman Modes ◽  
Integrated Intensities

Polyparaphenylene (PPP)-based carbons heat-treated at temperatures (THT) from 600 °C up to 3000 °C have been characterized both structurally and in terms of their physical properties. Special attention is given to PPP heat-treated at 700 °C (denoted by PPP-700), since samples heat-treated to this temperature were observed to have exceptionally high lithium affinities when electrochemically doped with Li. At low THT below 700 °C, it is found that the local structure of PPP-based samples can be characterized mostly in terms of a disordered polymer. As a result of heat treatment to high temperature, PPP-based carbon shows graphitization behavior with regard to x-ray diffraction d002 (graphite c-axis d-spacing) development and to the increase of the Raman IG/ID intensity ratio (where IG and ID are the integrated intensities of the 1580 cm−1 and 1360 cm−1 Raman modes, respectively), as is found in so-called graphitizing carbons. However, development of the c-axis crystallite size (Lc) is restricted to very small values, in the range of so-called nongraphitizing carbons, while the a-axis crystallite size (La) attains values up to roughly 120 Å for heat treatments near 3000 °C. These structural properties of PPP-based carbons are consistent with the observed electrical characteristics and their dependence on THT. Low temperature magnetic susceptibility measurements were analyzed, along with Raman spectra, allowing for the characterization of disorder in terms of localized spin states for several heat-treated PPP samples. By interpreting the results of these various characterization techniques, we are able to present an insightful perspective on the nature of PPP-based carbons and the role of PPP-700 as an effective lithium host material for secondary battery applications.

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