scholarly journals Structural and Morphological Studies of Nanocrystalline Ceramic BaSr0.9Fe0.1TiO4

2014 ◽  
Vol 41 ◽  
pp. 100-117 ◽  
Author(s):  
Reenu Jacob ◽  
Harikrishnan G. Nair ◽  
Jayakumari Isac
Keyword(s):  
Perovskite Phase ◽  
Piezoelectric Materials ◽  
High Energy ◽  
Milling Process ◽  
Sem Analysis ◽  
Lead Free ◽  
X Ray Diffraction ◽  
Software Analysis ◽  
Morphological Studies ◽  
Hall Plot

The development of lead-free piezoelectric materials have gained great attention for the consideration of environmental protection. Nanosized BaSr0.9Fe0.1TiO4, a lead free perovskite phase structured ceramic was prepared via a high-energy ball milling process through mechanically assisted synthesis. The sample was analyzed by X-ray Diffraction (XRD), SEM and EDX. The XRD results and XPERT-PRO software analysis confirmed the orthorhombic system of the sample. Scanning Electron Microscopy (SEM) analysis revealed that its crystallite size is in the nanometer range. The grain size was less than 100 nm and showed a strong tendency for agglomeration. It also confirmed with the calculated value from Debye Scherrer’s formula. EDX spectrum shows the elemental composition of the sample. Williamson-Hall Plot method was used to evaluate the size and lattice strain. The dislocation density and the morphology index of the sample were also calculated.

High-Energy Ball Milling and Sintering of Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B Powders Mixtures

2014 ◽  
Vol 802 ◽  
pp. 20-24 ◽  
Author(s):  
Lucas Moreira Ferreira ◽  
Luciano Braga Alkmin ◽  
Érika C.T. Ramos ◽  
Carlos Angelo Nunes ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Ball Milling ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Heat Treated ◽  
Equilibrium Structures ◽  
Rotary Speed ◽  
Steel Balls

The milling process of elemental Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B (at-%) powder mixtures were performed in a planetary Fritsch P-5 ball mill using stainless steel vials (225 mL) and hardened steel balls (19 mm diameter). Ball-to-powder weight ratio of 10:1 and a rotary speed of 300 rpm were adopted, varying the milling time. Wet milling (isopropyl alcohol) for 20 more minutes was used to increase the yield powder in to the vial. Following the Ti-Ta-Si-B powders milled for 600 min were heat-treated at 1100°C for 1 h in order to obtain the equilibrium structures. The milled powders and heat-treated samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Supersaturated Ti solid solutions were formed during ball milling of Ti-Ta-Si-B powders while that the Ti5Si3 phase was formed after milling for 620 min of the Ta-richer powder mixture only. The particles sizes were initially increased during the initial milling times, and the wet milling provided the yield powder into the vials. A large amount of pores was found in both the sintered samples which presented the formation of the TiSS,(ss-solid solution) Ti6Si2B and TiB.

scholarly journals Influence of ZnO addition and milling process on structure and conductivity of BaCe0.2Zr0.7Y0.1O3-δ ceramics

2021 ◽  
Vol 15 (3) ◽  
pp. 288-296
Author(s):  
Ana Ana Kaori de Oliveira Ouba ◽  
Adilson Chinelatto ◽  
Edson Grzebielucka ◽  
Kethlinn Ramos ◽  
Janaina Borcezi ◽  
...  
Keyword(s):  
Secondary Phase ◽  
Linear Shrinkage ◽  
High Energy ◽  
Milling Process ◽  
Sintering Aids ◽  
X Ray Diffraction ◽  
Sintering Aid ◽  
Secondary Phase Formation ◽  
Precursor Powders ◽  
Perovskite Lattice

Precursor powders for BaCe0.2Zr0.7Y0.1O3-?(BCZY27) ceramics were synthesized by a modified Pechinimethod and calcined at 900?C for 12 h. The calcined BCZY27 powders were milled in eccentric and in high energy mill with the addition of 2 and 4mol% ZnO as sintering aid. The effects of milling and sintering aids on the sinterability and electrical conductivity were studied. The linear shrinkage in thermomechanical analyses started at 1050?C for the BCZY27 with 4mol% ZnO processed in eccentric mill. Theoretical density above of 90%TD was obtained for the BCZY27 milled with 4mol% ZnO and sintered at 1400?C for 4h. X-ray diffraction analysis of the BCZY27 ceramics sintered at 1400?C confirmed the presence of BaCe0.2Zr0.7Y0.1O3-? and Y0.4Ce0.6O1.8 phases. The incorporation of Zn into perovskite lattice leads to the secondary phase formation. SEM and EDS analyses confirmed the presence of Y0.4Ce0.6O1.8 phase. The sintering was assisted by BaO-ZnO eutectic, which was reflected by the increase of activation energy values for grain boundary conduction. The milling processing did not affect the conductivity properties. The obtained BCZY27 dense sample has conductivity of 7.60 ? 10?3 S/cm at 500?C.

Microstructure and Oxidation Resistance of Mechanically Alloyed and Sintered Ni-Nb and Ni-Nb-Ta Alloys

2017 ◽  
Vol 899 ◽  
pp. 19-24
Author(s):  
Lucas Moreira Ferreira ◽  
Stephania Capellari Rezende ◽  
Antonio Augusto Araújo Pinto da Silva ◽  
Gael Yves Poirier ◽  
Gilberto Carvalho Coelho ◽  
...  
Keyword(s):  
Ball Milling ◽  
Oxidation Resistance ◽  
Energy Dispersive Spectrometry ◽  
High Energy ◽  
Milling Process ◽  
Ternary Alloys ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Static Oxidation ◽  
Energy Ball

The present work reports on the microstructure and oxidation resistance of Ni-25Nb, Ni-20Nb-5Ta and Ni-15Nb-10Ta alloys produced by high-energy ball milling and subsequent sintering. The sintered samples were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometry, and static oxidation tests. Homogeneous microstructures of the binary and ternary alloys indicated the major presence of the β-Ni3Nb compound as matrix, which dissolved large amounts of tantalum. Consequently, the β-Ni3Nb peaks moved toward the direction of smaller diffraction angles. Iron contamination lower than 6.7 at.-% was detected by EDS analysis, which were picked-up during the previous ball milling process. After the static oxidation tests (1100°C for 4 h) the sintered Ni-25Nb, Ni-20Nb-5Ta and Ni-15Nb-10Ta alloys presented mass gains of 31.5%, 30.5% and 28.8%, respectively. Despite the higher densification of the Ni-15Nb-10Ta alloy, the results suggested that the tantalum addition contributed to improve the oxidation resistance of the β-Ni3Nb compound.

SYNTHESIS OF NANO-CRYSTALLINE Cu-Cr ALLOY BY MECHANICAL ALLOYING

2012 ◽  
Vol 05 ◽  
pp. 496-501 ◽  
Author(s):  
S. SHEIBANI ◽  
S. HESHMATI-MANESH ◽  
A. ATAIE
Keyword(s):  
Mechanical Alloying ◽  
Structural Evolution ◽  
High Energy ◽  
Lattice Parameter ◽  
Control Agent ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Nano Crystalline ◽  
High Energy Ball Mill ◽  
Energy Ball

In this paper, the influence of toluene as the process control agent (PCA) and pre-milling on the extension of solid solubility of 7 wt.% Cr in Cu by mechanical alloying in a high energy ball mill was investigated. The structural evolution and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The solid solution formation at different conditions was analyzed by copper lattice parameter change during the milling process. It was found that both the presence of PCA and pre-milling of Cr powder lead to faster dissolution of Cr . The mean crystallite size was also calculated and showed to be about 10 nm after 80 hours of milling.

Effect of Milling Speed on the Synthesis of In-Situ Cu-25 Vol. % WC Nanocomposite by Mechanical Alloying

2012 ◽  
Vol 59 (2) ◽  
Author(s):  
Nurulhuda Bashirom ◽  
Nurzatil Ismah Mohd Arif
Keyword(s):  
Stainless Steel ◽  
Mechanical Alloying ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
The Matrix ◽  
Steel Balls

This paper presents a study on the effect of milling speed on the synthesis of Cu-WC nanocomposites by mechanical alloying (MA). The Cu-WC nanocomposite with nominal composition of 25 vol.% of WC was produced in-situ via MA from elemental powders of copper (Cu), tungsten (W), and graphite (C). These powders were milled in the high-energy “Pulverisette 6” planetary ball mill according to composition Cu-34.90 wt% W-2.28 wt% C. The powders were milled in different milling speed; 400 rpm, 500 rpm, and 600 rpm. The milling process was conducted under argon atmosphere by using a stainless steel vial and 10 mm diameter of stainless steel balls, with ball-to-powder weight ratio (BPR) 10:1. The as-milled powders were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). XRD result showed the formation of W2C phase after milling for 400 rpm and as the speed increased, the peak was broadened. No WC phase was detected after milling. Increasing the milling speed resulted in smaller crystallite size of Cu and proven to be in nanosized. Based on SEM result, higher milling speed leads to the refinement of hard W particles in the Cu matrix. Up to the 600 rpm, the unreacted W particles still existed in the matrix showing 20 hours milling time was not sufficient to completely dissolve the W.

(1-x)(K0.475Na0.475Li0.05)(Nb0.975Sb0.025)O3-xBiFeO3 Lead-Free Piezoelectric Ceramics with CuO Sintering Aid

2011 ◽  
Vol 687 ◽  
pp. 228-232
Author(s):  
Yong Jie Zhao ◽  
Yu Zhen Zhao ◽  
Rong Xia Huang ◽  
Rong Zheng Liu ◽  
He Ping Zhou
Keyword(s):  
Electrical Properties ◽  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Piezoelectric Ceramics ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Mechanical Quality Factor ◽  
Lead Free ◽  
X Ray Diffraction ◽  
Diffraction Patterns

(1-x) (K0.475Na0.475Li0.05)(Nb0.975Sb0.025)O3-xmolBiFeO3 (x=0, 0.002, 0.004, 0.006, 0.008) doped with 0.8mol%CuO lead-free piezoelectric ceramics were prepared by the solid state reaction technique. X-ray diffraction patterns suggested that all the ceramics presented perovskite structure. The compositional dependence of the phase structure and the electrical properties of the ceramics were studied. The ceramic (x=0.002) near room temperature exhibited excellent electrical properties (piezoelectric constant d33=172pC/N, planar electromechanical coupling factor kp=0.43, and dielectric constant =418). A relatively high mechanical quality factor (Qm=200) was also obtained in this particular composition. All these results revealed that this system might become a promising candidate for lead-free piezoelectric materials.

Mechanosynthesis of La0.95Sr0.05Ga0.90Mg0.10O3-δ

2008 ◽  
Vol 587-588 ◽  
pp. 931-935
Author(s):  
Priscila Gonçalves ◽  
Filipe M. Figueiredo
Keyword(s):  
Perovskite Phase ◽  
Average Crystallite Size ◽  
High Energy ◽  
Equivalent Diameter ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Planetary Rotation ◽  
Transmission Electron ◽  
Size Estimates

The production of La0.95Sr0.05Ga0.90Mg0.10O3-δ powders was achieved at room temperature by a mechanosynthesis route in a high energy planetary ball mill starting from a mixture of lanthanum, strontium, gallium and magnesium oxides. The milling was carried out in nylon containers, using zirconia balls and a balls:powder mass ratio of 10:1. The planetary rotation was kept constant at 650 rotations per minute (rpm), and the container at 1300 rpm, in the opposite direction. The formation of the perovskite phase was detected from the early milling stages and nearly completed after milling for 360 min, as shown by powder X-ray diffraction. Transmission electron microscopy results revealed that powders consist of agglomerates of homogeneous, crystalline particles with an average equivalent diameter of about 16-17 nm, in excellent agreement with average crystallite size estimates obtained from X-ray diffraction.

Preparation of Nb-40Ti Powders by High-Energy Milling

2005 ◽  
Vol 498-499 ◽  
pp. 146-151
Author(s):  
Y.A. Giffoni ◽  
Erika Coaglia Trindade Ramos ◽  
Ana Sofia Ramos ◽  
Hugo Ricardo Zschommler Sandim ◽  
M.T.T. Pacheco
Keyword(s):  
Solid Solution ◽  
High Energy ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
High Energy Milling ◽  
Porous Ti ◽  
Titanium Hydride Powder ◽  
Tih2 Powder ◽  
Ti Powder

Porous Ti-Nb alloys are promising candidates for biomedical applications. In the present study, alloy powders containing 60 wt-% Nb were prepared by high-energy milling of Nb, Ti, and/or TiH2 powders. The high-energy milling process was carried out in a planetary ball mill. The starting and as-milled materials were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). Elemental (Nb, and Ti) and TiH2 powder mixtures with composition Nb-40wt%Ti were mechanically alloyed for 2 to 30 h. The formation of a BCC Nb(Ti) solid solution by high-energy milling using elemental Ti powder to produce Nb-40Ti was observed after milling for 30 h. A HCP-Ti solid solution was formed after milling for 30 h due to the partial decomposition of titanium hydride powder mixture during high-energy milling.

Combustion Synthesis of Mechanically-Activated Nb-Al Mixtures

2005 ◽  
Vol 498-499 ◽  
pp. 152-157 ◽  
Author(s):  
Fabiana Buracovas ◽  
Valéria S. Gonçalves ◽  
Cláudio José da Rocha ◽  
Ricardo Mendes Leal Neto
Keyword(s):  
Water Immersion ◽  
Control Agent ◽  
Milling Process ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Process Control Agent ◽  
Effective Dispersion ◽  
Powder Mass ◽  
Ignition And Combustion ◽  
Milled Powders

In this work shake milling were used to mechanically activate Nb – Al powder mixtures at different relative proportions (Nb80Al, Nb65Al, Nb54Al e Nb42Al). All milling process parameters were unchanged, e.g., powders mass, ball/powder mass ratio, balls diameter, quantity and kind of process control agent. Uniaxially compacted cylindrical pellets of milled powders were vacuum reacted. After a two-step degassing treatment (290°C for 0.5 h and 400°C for 4 h), samples were heated at 30°C/min. Ignition and combustion temperatures were measured by a thermocouple inserted in a hole drilled into the pellets. The microstructure of milled powders and reacted pellets were characterized by X-ray diffraction and SEM analysis. Bulk density of the pellets was measured by water immersion (Archimedes). The results showed a decrease of both ignition and combustion temperature with mechanical activation as seen by comparison with reacted pellets of the same composition not mechanically activated (simple mixtures). By increasing the heating hate the completeness of the reactions were improved. The lower the aluminum contents the lower the ignition and combustion temperatures and also the densification. The decrease on ignition temperature was caused by a more effective dispersion (and so more activation) attained by samples with lower aluminum content.

Evaluation of Tribological Properties of Organoclay Reinforced UHMWPE Nanocomposites

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Abdul Samad Mohammed ◽  
Annas bin Ali ◽  
Merah Nesar
Keyword(s):  
Tribological Properties ◽  
Large Scale ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
High Energy ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Uniform Dispersion ◽  
Ultrahigh Molecular Weight ◽  
Energy Ball

The current study is aimed to investigate the tribological properties of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with organoclay Cloisite (C15A). Nanocomposites are prepared using a high energy ball milling process followed by hot pressing. Three different loadings of 0.5 wt.%, 1.5 wt.%, and 3 wt.% of C15A, respectively, are used as reinforcement. Results from the ball-on-disk wear tests showed that nanocomposites reinforced with 1.5 wt.% of C15A exhibited best wear resistance and lower coefficient of friction (COF), with C15A reducing the wear rate by 41% and the COF by 38%, when compared to the pristine UHMWPE. These improvements are attributed to the uniform dispersion of the nanosized clay platelets preventing large-scale material removal and formation of a thin tenacious, continuous transfer film on the counterface for C15A organoclay composites. X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical profilometry are used to characterize the morphology of the nanocomposites and the wear tracks. SEM images of worn surfaces indicated more abrasive wear for the case of pristine UHMWPE as compared to organoclay composites.

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