scholarly journals Effect of Synthesis and Sintering Temperatures on K0.5Na0.5NbO3 Lead-Free Piezoelectric Ceramics By Microwave Heating

2021 ◽  
Author(s):  
Anggel Lagunas ◽  
Maria Guadalupe Navarro-Rojero ◽  
Maria Dolores Salvador ◽  
Jose Manuel Catalá ◽  
Amparo Borrell
Keyword(s):  
Intermediate Phase ◽  
Piezoelectric Materials ◽  
Microwave Sintering ◽  
Single Mode ◽  
Piezoelectric Ceramics ◽  
Lead Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Xrd Patterns

Abstract Powders of K0.5Na0.5NbO3 lead-free piezoelectric ceramics were successfully synthesized via conventional and microwave-assisted heating. A single-mode microwave equipment was used to perform the synthesis following the mixed oxide route and then sintering at different temperatures. The synthesized powders obtained and then sintered by microwave and conventional methods were evaluated by thermogravimetry analysis, X-ray diffraction (XRD), and field emission scanning electron microscopy. Microwave synthesis processing for 10 minutes at 650 ºC using a heating rate of 30 ºC/min promotes the formation of 2 K0.5Na0.5NbO3 nanoparticles. Perovskite structure formed during calcination shows the coexistence of tetragonal-orthorhombic geometry according to XRD patterns. The microwave-obtained particles are consistent with the theoretical stoichiometry. Particle size increases as the reaction temperature is increased from 650 ºC to 800 ºC. An intermediate phase (K,Na)2Nb4O11 is formed in the entire range of synthesis temperatures studied. The samples obtained by microwave sintering show a structure similar to the samples sintered by the conventional method. However, the porosity observed in the microstructure of the microwave-sintered piezoelectric materials affects the density of the material, and these defects cause a decrease in the dielectric values.

(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.

The Microwave Electromagnetic Properties of Sr2+ Doped DyFeO3

2011 ◽  
Vol 197-198 ◽  
pp. 405-408
Author(s):  
Shao Teng Yan ◽  
Xiao Gu Huang ◽  
Feng Dai ◽  
Peng De Han ◽  
Li Xi Wang ◽  
...  
Keyword(s):  
Single Phase ◽  
Intermediate Phase ◽  
Electromagnetic Properties ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Xrd Patterns ◽  
Perovskite Type ◽  
Peak Value

Perovskite type ferrite doped with Sr2+, Dy1-xMxFeO3(x = 0.0, 0.05, 0.15, 0.25) were prepared by the conventional solid-state reaction. The structure and electromagnetic properties of the calcined samples were studied using powder X-ray diffraction (XRD, Rigaku D/Max-2500) and network analyzer (Agilent 8722ET). All the XRD patterns showed the single phase of the perovskite type ferrite without other intermediate phase when x≤0.25. The electromagnetic properties of the samples have been studied at the frequency range from 2 GHz to 18 GHz. The ε′ and ε′′ values were improved significantly. Both the values of ε′ and ε′′ increase with the increasing content of the doped cations Sr2+, and the peak value of ε′′ was about 2.2 at 12.1 GHz position when x = 0.25.

Interfacial Reactions Between Ain Substrate And 4-A Family Elements

1995 ◽  
Vol 398 ◽  
Author(s):  
Yong Du ◽  
Xiangjun He ◽  
Kun Tao
Keyword(s):  
Direct Product ◽  
Vapour Deposition ◽  
Rutherford Backscattering Spectrometry ◽  
Interfacial Reactions ◽  
Physical Vapour Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Diffraction Peaks ◽  
Xrd Patterns

ABSTRACTInterfacial reactions between A1N substrate and 4A-family elements including Ti, Zr and Hf were studied. The samples were prepared by Physical Vapour Deposition and annealed at different temperatures from 200°C to 800°C. X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS) were employed to detect the compounds formed at the interfaces between them. For Ti/AIN system, when the samples were annealed from 600°C to 800°C for 1 hour, it was found from XRD patterns that TiAl3, TiN, and Ti4N3.x including Ti2N were formed at Ti/AIN interface. With the temperature increasing, the intensities of Ti, TiN(200), Ti2N and Ti4N3.x diffraction peaks decreased while that of TiAl3 and TiN(111) increased. For Zr/AlN system, it was found that the reactions between Zr and AlN resulted in the formation of Al3Zr at about 300°C and Al2Zr at about 500°C. According to RBS spectra, it can be assumed that Al3Zr was the direct product by the reaction between AlN and Zr and Al2Zr was formed by the reaction between Al3Zr and Zr. For Hf/AlN system, however, even the sample was annealed at 800°C, no compound resulted from interfacial reactions was detected.

Morphology and microstructural properties of TiO2 nanopowders doped with trivalent Al and Ga cations

2000 ◽  
Vol 15 (10) ◽  
pp. 2080-2086 ◽  
Author(s):  
L. E. Depero ◽  
A. Marino ◽  
B. Allieri ◽  
E. Bontempi ◽  
L. Sangaletti ◽  
...  
Keyword(s):  
Average Crystallite Size ◽  
Microstructural Properties ◽  
Crystallite Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructural Parameters ◽  
Different Temperatures ◽  
Trivalent Cations ◽  
Tio2 Nanopowders ◽  
Xrd Patterns

The effects of doping on the morphological and microstructural properties of TiO2 nanopowders produced by laser pyrolysis were investigated mainly by x-ray diffraction (XRD) and electron microscopy. Samples of TiO2 powders were prepared by doping with different trivalent cations (Al and Ga). The powders were calcined at different temperatures in the range 400–1000 °C for 18 h, as well as at constant T = 700 °C up to 160 h. After each thermal treatment, XRD patterns were collected. The analysis of XRD patterns allowed us to estimate the microstrains and average crystallite size and to observe the evolution of the microstructural parameters with temperature. Both Al and Ga inhibited the crystallite growth of TiO2 anatase and the rutile phases, this effect being larger in the Al-doped powders.

Ferroelastic Domains and Anisotropy in Lead Free Piezoelectrics

2011 ◽  
Vol 702-703 ◽  
pp. 995-998
Author(s):  
Bin Zhi Li ◽  
Chris Fancher ◽  
John E. Blendell ◽  
R. Edwin Garcia ◽  
Keith J. Bowman
Keyword(s):  
Thin Film ◽  
Crystallographic Texture ◽  
Piezoelectric Materials ◽  
Ferroelectric Domain ◽  
Lead Free ◽  
Polycrystalline Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ferroelastic Domains ◽  
2D And 3D

Our research investigates the correlations between domain texture and microstructural features, including crystallographic texture in bulk and thin film polycrystalline materials to understand the development of piezoelectric and other anisotropic properties in a number of rapidly evolving lead free piezoelectric materials. We investigate approaches to understanding polarization distributions by starting from polarization measurements. In addition, 2D and 3D microstructural simulations are carried out in all types of ferroelectrics to rationalize and then engineer their equilibrium and kinetic response. This paper discusses recent findings associated with bulk piezoelectricity, phase stability, and ferroelastic and ferroelectric domain motion for materials such as Ba(Ti0.8Zr0.2)O3-x(Ba0.7Ca0.3)TiO3 (BZT-BCT) and Bi0.5Na0.5TiO3 (BNT). Conventional and synchrotron-based x-ray diffraction, electron and optical microscopy and piezoelectric characterization techniques are employed to assess texture, both as a function of poling and temperature. The coupling between microstructure and the inherent directional biases fundamental to piezoelectric and ferroelectric performance enable consideration of orientation and anisotropy in systems with unique constraints.

Magnetic Properties of Mg0.4Ca0.6Fe2O4 Nanoparticles Synthesized by Sol-Gel Method for Hyperthermia Treatment

2014 ◽  
Vol 631 ◽  
pp. 193-197
Author(s):  
A.M. Escamilla-Pérez ◽  
D.A. Cortés-Hernández ◽  
J.M. Almanza-Robles ◽  
D. Mantovani ◽  
P. Chevallier
Keyword(s):  
Magnetic Properties ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Hyperthermia Treatment ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Different Temperatures ◽  
Xrd Patterns

Powders of Mg0.4Ca0.6Fe2O4were prepared by sol-gel using ethylene glycol and Mg, Ca and Fe nitrates as starting materials. Those powders were heat treated at different temperatures (300, 400, 500 and 600 °C) for 30 min. The materials obtained were characterized by X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The Ca-Mg ferrite with the most appropriate magnetic properties was further analyzed by transmission electron microscopy (TEM). The heating capability of the nanoferrites was also tested via magnetic induction. The XRD patterns of these Ca-Mg ferrites showed a cubic inverse spinel structure. Furthermore, neither traces of hematite nor orthorhombic Ca ferrite phases were detected. Moreover, all the Ca-Mg ferrites are superparamagnetic and the particle size distribution of these Ca-Mg magnetic nanoparticles exhibits an average diameter within the range of 10-14 nm. The needed temperature for hyperthermia treatment was achieved at around 12 min.

Phase Structure and Electrical Properties of Bi1/2Na1/2TiO3-KNbO3 Lead-Free Piezoelectric Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 184-187 ◽  
Author(s):  
Wen Zhong Lu ◽  
Gui Fen Fan ◽  
Xiao Hong Wang ◽  
Fei Liang
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Piezoelectric Properties ◽  
Extreme Values ◽  
Piezoelectric Ceramics ◽  
Lead Free ◽  
Fabrication Technique ◽  
X Ray Diffraction ◽  
Depolarization Temperature ◽  
X Ray

Lead-free (1-x) Bi1/2Na1/2TiO3-xKNbO3 (x=0, 0.01, 0.02, 0.04, 0.05 0.06, 0.10) piezoelectric ceramics were prepared by conventional ceramics fabrication technique. The results of x-ray diffraction (XRD) show that these ceramics possess pure perovskite structures with a symmetry transition from rhombohedral to cubic at about x = 0.05. The piezoelectric properties of these ceramics were reported and found to reach extreme values at x = 0.04 with d33 up to 113pC/N and kp up to 22%. The temperature dependence of dielectric constant and dielectric loss of these ceramics were also investigated. The Curie temperature and depolarization temperature dropped with the increase of KNbO3 amount.

X-Ray Diffraction Patterns of Oil Palm Empty Fruit Bunch Fibers with Varying Crystallinity

2015 ◽  
Vol 1087 ◽  
pp. 321-328 ◽  
Author(s):  
Fatin Afifah Ahmad Kuthi ◽  
Khairiah Haji Badri ◽  
Azlin Mohmad Azman
Keyword(s):  
Acid Hydrolysis ◽  
Oil Palm ◽  
Empty Fruit Bunch ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Before And After ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Xrd Patterns

Crystallinity of oil palm fiber from empty fruit bunch (EFB) with and without tretaments was studied by analyzing the X-ray diffraction (XRD) pattern. In this paper, we focused on the effect of acid hydrolysis onto EFB on the crystallinity of the extracted cellulose. The reaction was carried out by soaking EFB in 1% (v/v) aqueous sulfuric acid (H2SO4) at different temperatures of 120, 130 and 140°C for 1 h. The XRD patterns significantly showed changes in the 2θ peaks before and after the treatment. These changes were described in term of polymorphs type present, reflection and allomorphs of the samples. XRD peak high and XRD deconvolution methods were used to calculate and compare the percentage of crystallinity of untreated EFB (UT-EFB) and acid hydrolyzed samples (AH-EFB). Based on the calculation, increment of about 1.3 times and 1.5 times were achieved by using WAXS and XRD deconvolution methods respectively. This is due to the removal of amorphous part contributed by lignin, hemicellulose and cellulose. Fourier Transform infrared (FTIR) spectra showed the presence of similar peaks in AH-EFB and commercial microcrystalline cellulose (C-MCC) at 1427, 1315, 895 and 1022 cm-1. The micrographic features showed the acid hydrolysis had successfully took place and separated the EFB microfibrils bundles.

Property Comparison of CuInSi Films Prepared by Multilayer Synthesized and Magnetron Co-Sputtering

2011 ◽  
Vol 110-116 ◽  
pp. 3755-3761
Author(s):  
Jian Sheng Xie ◽  
Jin Hua Li ◽  
Ping Luan
Keyword(s):  
Grain Size ◽  
Film Surface ◽  
Nanocomposite Films ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Absorption Studies ◽  
Nanocomposite Thin Films ◽  
Different Temperatures ◽  
Xrd Patterns

Using magnetron sputtering technology, the CuInSi nanocomposite thin films were prepared by magnetron co-sputtering method and multilayer synthesized method respectively,and followed by annealing in N2 atmosphere at different temperatures. The structure of CuInSi nanocomposite films were detected by X-ray diffraction (XRD); X-ray diffraction studies of the annealed films indicate the presence of CuInSi, the peak of main crystal phase is at about 2θ=42.308°,meanwhile,there are In2O3 peak and other peaks in the XRD patterns of films. The morphology of the film surface was studied by SEM. The SEM images show that the crystalline of the film prepared by multilayer synthesized method was granulated, But the crystalline of the film prepared by magnetron co-sputtering with needle shape. The grain size is a few hundred angstroms. The band gap has been estimated from the optical absorption studies and found to be about 1.40 eV for the sample by magnetron co-sputtering, and 1.45eV for the sample by multilayer synthesized, but all changes with the purity of CuInSi.

scholarly journals Microstructure and Mechanical Behavior of Hot Extruded Aluminum/Tin-Bismuth Composites Produced by Powder Metallurgy

2020 ◽  
Vol 10 (8) ◽  
pp. 2812 ◽  
Author(s):  
Adnan Khan ◽  
Penchal Reddy Matli ◽  
Muddasir Nawaz ◽  
Manohar Reddy Mattli ◽  
Gururaj Parande ◽  
...  
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
Microwave Sintering ◽  
Hot Extrusion ◽  
Industrial Applications ◽  
Mechanical And Thermal Properties ◽  
Strengthening Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Patterns

In this study, Al-BiSn composites were synthesized by a combination of microwave sintering and hot extrusion processes. The structural, morphological, mechanical, and thermal properties were investigated to elucidate the role of Bi60Sn40 (BiSn) alloy content (5, 10, and 15 wt.%) in modifying the properties of Al-BiSn composites. The X-ray diffraction (XRD) patterns confirmed the presence of aluminum and BiSn particles. Distribution of BiSn particles in Al-BiSn composites was confirmed by field emission scanning electron microscopy associated with energy dispersive X-ray analysis (FE-SEM-EDX). Results indicated that hot extruded Al-(15 wt.% BiSn) composite exhibits maximum hardness (78 ± 4 Hv) and tensile strength (185 ± 3 MPa), which were 117% and 58% improvements, respectively, compared to pure Al. This improvement in mechanical properties can be attributed to the strengthening effect of BiSn particles. A decline in the values of the coefficient of thermal expansion (CTE) with an increasing amount of BiSn particles reflects the enhanced thermal stability of developed Al-BiSn composites. The promising properties of Al-BiSn composites make them suitable for many industrial applications.

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