scholarly journals SYNTHESIS AND CHARACTERIZATION OF LEAD-FREE PIEZOELECTRIC (K0.5Na0.5)NbO3 PRODUCED WITH IMPROVED CALCINATION TEMPERATURE

2020 ◽  
Vol 82 (2) ◽  
Author(s):  
Nor Amalina Ahmad ◽  
Dzetty Soraya Abdul Aziz ◽  
Norni Hidayawati Mat Daud ◽  
Rahim Noor ◽  
Amir Azam Khan
Keyword(s):  
Calcination Temperature ◽  
Sintering Temperature ◽  
Milling Process ◽  
Lead Free ◽  
Sintered Pellet ◽  
Sintering Process ◽  
Potassium Sodium Niobate ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure

Potassium sodium niobate (KNN) is one of the lead free piezoelectric material that catch the attention of researchers and also those in the industrial field because of its stable piezoelectric responses and environmental friendly composition. The recent development of KNN shows that many methods have been used to synthesize the KNN but the stoichiometric Ka0.5Na0.5NbO3 composition is extremely difficult to consolidate. One of the ways to overcome the problem is to precisely pre-calcine and use milling process for proper homogenization followed by natural sintering process. In this paper, attempt has been made to synthesize the KNN produced at 750 oC calcination temperature. The results of 1060oC sintering temperature for 2 hours show a good composition of KNN with orthorhombic crystal structure where the final sintered pellet can reach to a relative density up to 87.13 %. 

scholarly journals Pressureless Sintering of YIG Ceramics from Coprecipitated Nanopowders

2021 ◽  
Vol 7 (5) ◽  
pp. 56
Author(s):  
Yimin Yang ◽  
Xiaoying Li ◽  
Ziyu Liu ◽  
Dianjun Hu ◽  
Xin Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Calcination Temperature ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Secondary Phase ◽  
Coprecipitation Method ◽  
Pressureless Sintering ◽  
Densification Behavior ◽  
Sintering Process

Nanoparticles prepared by the coprecipitation method were used as raw materials to fabricate Y3Fe5O12 (YIG) ceramics by air pressureless sintering. The synthesized YIG precursor was calcinated at 900–1100 °C for 4 h in air. The influences of the calcination temperature on the phase and morphology of the nanopowders were investigated in detail. The powders calcined at 1000–1100 °C retained the pure YIG phase. YIG ceramics were fabricated by sintering at 1200–1400 °C for 10 h, and its densification behavior was studied. YIG ceramics prepared by air sintering at 1250 °C from powders calcinated at 1000 °C have the highest in-line transmittance in the range of 1000-3000 nm. When the sintering temperature exceeds 1300 °C, the secondary phase appears in the YIG ceramics, which may be due to the loss of oxygen during the high-temperature sintering process, resulting in the conversion of Fe3+ into Fe2+.

Effect of Process on the Dielectric Properties of BaTiO3-Based X9R Ceramics

2014 ◽  
Vol 906 ◽  
pp. 18-24 ◽  
Author(s):  
Bao Lin Zhang ◽  
Bin Bin Zhang ◽  
Ning Ning Wang ◽  
Jing Ming Fei
Keyword(s):  
Particle Size ◽  
Dielectric Properties ◽  
Milling Time ◽  
Sintering Temperature ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Sintered Ceramic ◽  
X Ray ◽  
Particle Size Analyzer

The effect of milling time and sintering process on the dielectric properties of BaTiO3-based X9R ceramics was investigated. The characterization of the raw powders and the sintered ceramic was carried out by X-ray diffraction and scanning electron microscopy. The particle size distribution of the mixed powders was examined by Laser Particle Size Analyzer. The results shown that with the milling time extended, the Cruie Peak was depressed, or even disappeared. Moreover, with the rise of sintering temperature, the dielectric constant of the ceramics increased and the dielectric loss decreased gradually. Eventually, by milling for 11h and sintering at 1090°Cfor 2h, good dielectric properties were obtained, which were ε25°C≥ 2526, εr/εr25°C≤± 12% (–55~200°C), tanδ≤1.12% (25°C).

Synthesis and Characterization of Pb(Zr0.52Ti0.48)O3 Properties via High Planetary Mill

2017 ◽  
Vol 888 ◽  
pp. 96-102
Author(s):  
Shafiza Afzan Sharif ◽  
Julie Juliewatty Mohamed ◽  
Hasmaliza Mohamed ◽  
Zainal Arifin Ahmad ◽  
Wan Azhar Wan Yusoff
Keyword(s):  
Sintering Temperature ◽  
Xrd Analysis ◽  
High Energy ◽  
Planetary Mill ◽  
Firing Process ◽  
Material System ◽  
Sintering Process ◽  
Grain Growth Behavior ◽  
Sintering Condition

In this work, the piezoelectric material system of Pb (Zr0.52Ti0.48)O3 ceramics were synthesized by conventional solid state via high energy planetary mill reaction. This process were chosen in order to skip the calcinations and implement a single firing process which very effective to reduce the possibility of PbO loss. The effect of sintering parameters on structural behavior of pure PZT ceramic was discussed in detail. Comprehensive studies have been carried out in order get optimum parameter for sintering process, thus improved the performance of the pure PZT ceramics. Grain size properties of Pb (Zr0.52Ti0.48)O3 ceramics increased with increasing the sintering temperature and duration. However longer sintering condition (1200 °C, 3 hours) causes excessive PbO loss which leads to presence new phases in XRD analysis, promote grain growth behavior with inhomogenous microstructure and tend to have more pores.

Preparation and characterization of low-cost high-performance mullite-quartz ceramic proppants for coal bed methane wells

2018 ◽  
Vol 25 (5) ◽  
pp. 957-961 ◽  
Author(s):  
Kaiyue Wang ◽  
Huijun Wang ◽  
Yi Zhou ◽  
Guomin Li ◽  
Yaqiao Wu ◽  
...  
Keyword(s):  
High Performance ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Low Cost ◽  
Quartz Ceramic ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Sintering Process ◽  
Flow Mechanism

AbstractIn this study, the mullite-quartz-based proppants were successfully prepared by using the coal gangue as the raw materials. Then, the effects of the additive and the sintering temperature on the composition, microstructure, and properties of the proppants were investigated. Results showed that the proppants sintered at 1250°C with the 10 wt% bauxite additive presented the best performance, which was very close to that of the quartz-proppant, and met the operational requirements of the 52 MPa coal bed methane wells. The viscous flow mechanism of the liquid phase formed during the sintering process also promoted the arrangement of the grains, thus benefiting the densification and the strength of the proppants.

New potassium-sodium niobate lead-free piezoceramic: Giant-d33 vs. sintering temperature

2014 ◽  
Vol 115 (11) ◽  
pp. 114104 ◽  
Author(s):  
Jiagang Wu ◽  
Xiaopeng Wang ◽  
Xiaojing Cheng ◽  
Ting Zheng ◽  
Binyu Zhang ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Lead Free ◽  
Sodium Niobate ◽  
Potassium Sodium Niobate ◽  
Potassium Sodium

Preparation and Characterization of Al2TiO5- Si3N4 Composites by Reaction Sintering Process

2011 ◽  
Vol 284-286 ◽  
pp. 201-204
Author(s):  
Rui Sheng Wang ◽  
Jun Hong Zhao ◽  
Heng Yong Wei ◽  
Shao Wei Yao
Keyword(s):  
Mechanical Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Reaction Sintering ◽  
Sintering Process ◽  
Soaking Time ◽  
Sintering Properties ◽  
The One

Al2TiO5-Si3N4 composites were prepared by reaction sintering process using Al2TiO5 and α-Si3N4 powders as raw materials. The effect ofsintering temperature, soaking time and Si3N4 content on the sintering properties of the composites was studied. The results showed that the best sintering temperature and soaking time were 1550 °C and 2 h, respectively. The samples with 15 wt% of Si3N4 addition had good sintering properties, and its mechanical strength was 28.96 MPa, which was 2 times of the one of the samples without Si3N4 addition.

Rietveld Refinement and DC Conductivity of Na0.5K0.5NbO3 Ceramics

2012 ◽  
Vol 585 ◽  
pp. 210-213 ◽  
Author(s):  
Monica Sindhu ◽  
N. Ahlawat ◽  
Sujata Sanghi ◽  
Ashish Agarwal ◽  
A. Ashima ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rietveld Refinement ◽  
Base Material ◽  
Polycrystalline Sample ◽  
Solid State Reaction Method ◽  
Dc Conductivity ◽  
Potassium Sodium Niobate ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Refinement Method

Potassium Sodium Niobate, Na0.5K0.5NbO3 is a promising base material for lead free piezoceramics. The polycrystalline sample Na0.5K0.5NbO3 was synthesized using solid state reaction method. The crystal structure and phase purity was studied by XRD and analysed using Rietveld refinement method. Good agreement was observed between the observed and calculated patterns in Rietveld refinement. The refinement inferred orthorhombic crystal structure with Amm2 space group. The impedance spectroscopy of the sample was performed in frequency range 10 Hz to 7 MHz in temperature range 573K to 703K. The activation energy was obtained to be 0.67eV from the reciprocal temperature variation of dc conductivity which follows the Arrhenius law.

On the Formation of Silicide Precipitates in Niobium-Silicide Based Composites

1998 ◽  
Vol 552 ◽  
Author(s):  
B. P. Bewlay ◽  
R. J. Grylls ◽  
H. L. Fraser
Keyword(s):  
Crystal Structure ◽  
Directional Solidification ◽  
Orientation Relationship ◽  
High Temperatures ◽  
Aircraft Engines ◽  
Orthorhombic Crystal ◽  
Detailed Characterization ◽  
Orthorhombic Crystal Structure ◽  
Very High

ABSTRACTComposites based on Nb-Si are attractive candidates for use as structural materials at the very high temperatures required for future aircraft engines. The composites described were produced by directional solidification, which gives a microstructure consisting of Nb dendrites with an Nb3Si-Nb eutectic. The aim of this paper is to provide a detailed characterization of precipitates observed in the Nb dendrites in both binary and higher-order alloys. The precipitates possess the Nb3Si stoichiometry, but not the stable Nb3Si structure. The precipitates form a metastable orthorhombic crystal structure which is related to the Nb matrix via a simple orientation relationship.

scholarly journals Structural and Electric Properties of MnO2-Doped KNN-LT Lead-Free Piezoelectric Ceramics

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 705
Author(s):  
Yunfeng Deng ◽  
Junjun Wang ◽  
Chunxiao Zhang ◽  
Hui Ma ◽  
Chungeng Bai ◽  
...  
Keyword(s):  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Piezoelectric Ceramics ◽  
Relevant Information ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Potassium Sodium Niobate ◽  
Conventional Solid State Reaction ◽  
Dielectric And Piezoelectric Properties

Structural, ferroelectric, dielectric, and piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xmol%MnO2 lead-free piezoelectric ceramics with 0.0 ≤ x ≤ 0.3 were studied. The ceramic samples were synthesized through the conventional solid-state reaction method. The MnO2 addition can reduce the sintering temperature of KNLNT ceramics. Compared with undoped KNLNT ceramic, the piezoelectric measurements showed that piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xMnO2 were improved (d33 = 251 pC/N) when x = 0.1. In addition, KNLNT-xMnO2 ceramics have larger Pr(20.59~21.97 μC/cm2) and smaller Ec(10.77~6.95 kV/cm), which indicates MnO2 has excellent softening property, which improves the ferroelectric properties of KNLNT ceramics This work adds relevant information regarding of potassium sodium niobate K0.5Na0.5NbO3 (KNN) when doped Li, Ta, Mn at the B-site.

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