Microstructure and Electrical Properties of BaTiO3-Based PTC Ceramics Prepared from Nanopowders

2008 ◽  
Vol 368-372 ◽  
pp. 456-458
Author(s):  
Huan Liu ◽  
Shu Ping Gong ◽  
Dong Xiang Zhou ◽  
Chun Fang Cheng ◽  
Zhi Ping Zheng ◽  
...  
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Curie Temperature ◽  
Hydrothermal Method ◽  
Hydrothermal Treatment ◽  
Theoretical Density ◽  
Ceramic Samples ◽  
Average Grain Size ◽  
Donor Dopant ◽  
Cubic Structure

Dense PTC ceramics were prepared with BaTiO3 nanopowders synthesized by hydrothermal method. BaCO3 and Ti(OC4H9)4 were used as barium and titanium sources, and Y(NO)3·6H2O as the donor dopant respectively. The average grain size of the powders obtained after hydrothermal treatment at 160°C for 9h was about 30nm with cubic structure. Mn(NO3)2 was introduced to the as-prepared nanopowders in order to improve the PTC effect. After sintered at 1280°C, the PTC ceramic samples exhibited sufficient resistance jump ratio(1.086×103) around Curie temperature, the density of which was 5.81g/cm3(96.5% of the theoretical density).

scholarly journals Enhancing the electrical properties of high-Curie temperature BNT–PZT piezoceramics by oxides-hydrothermal method

AIP Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 075119
Author(s):  
Bo Li ◽  
Fei Zhu ◽  
Deyi Zheng ◽  
Chi pang ◽  
Zihao Fei
Keyword(s):  
Electrical Properties ◽  
Curie Temperature ◽  
Hydrothermal Method ◽  
High Curie Temperature

Effect of WO3 Doping on Microstructural and Electrical Properties of ZnO-Pr6O11 Based Varistor Materials

2013 ◽  
Vol 591 ◽  
pp. 54-60
Author(s):  
Xiu Li Fu ◽  
Yan Xu Zang ◽  
Zhi Jian Peng
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Grain Growth ◽  
Doping Level ◽  
Nonlinear Coefficient ◽  
Current Voltage ◽  
Average Grain Size ◽  
Current Voltage Characteristics ◽  
Voltage Performance

The effect of WO3doping on microstructural and electrical properties of ZnO-Pr6O11based varistor materials was investigated. The doped WO3plays a role of inhibitor in ZnO grain growth, resulting in decreased average grain size from 2.68 to 1.68 μm with increasing doping level of WO3from 0 to 0.5 mol%. When the doping level of WO3was lower than 0.05 mol%, the nonlinear current-voltage characteristics of the obtained varistors could be improved significantly with increasing amount of WO3doped. But when the doping level of WO3became higher, their nonlinear current-voltage performance would be dramatically deteriorated when more WO3was doped. The optimum nonlinear coefficient, varistor voltage, and leakage current of the samples were about 13.71, 710 V/mm and 13 μA/cm2, respectively, when the doping level of WO3was in the range from 0.03 to 0.05 mol%.

Study on Microstructure and Properties of BTBY Piezoelectric Ceramics with High Curie Temperature

2010 ◽  
Vol 156-157 ◽  
pp. 1541-1544
Author(s):  
Bo Li ◽  
Feng Gao ◽  
Liang Liang Liu ◽  
Bei Xu
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Curie Temperature ◽  
Grain Morphology ◽  
High Curie Temperature ◽  
Microstructure And Properties ◽  
New Phase ◽  
Dielectric Relaxor

(1-x)(0.6BIT-0.4BT)-xBiYbO3(BTBY) ceramics with high Curie temperature were prepared by the conventional processing. The effect of BiYbO3 content on the microstructure and electrical properties was investigated. The results show that the main phase of BTBY ceramics is BIT-BT, and a new phase BaBi4Ti4O15 (BBT) appeared. The grain morphology of BTPY ceramics are platelike and the grain size was significantly increased with increasing content of BiYbO3 .Tc of all the BTBY samples are above 440 . The BTBY ceramics show obvious dielectric relaxor characteristic. The dispersion factor γ, the dielectric constant εr, and the dielectric loss tanδ decreased with increasing the content of BiYbO3. When the content of BiYbO3 is 0.06, the optimal properties of BTBY ceramics are obtained, Tc is 457 , εr is 165, tanδ is 0.0223 and d33 is 10 pC·N-1.

Synthesis of Nanocrystalline 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 Powder by a Citrate Method

2008 ◽  
Vol 368-372 ◽  
pp. 103-105
Author(s):  
Zhi Bin Tian ◽  
Xiao Hui Wang ◽  
Ji Li ◽  
Wei Zhao ◽  
Long Tu Li
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Traditional Method ◽  
Sintering Temperature ◽  
Ph Value ◽  
Precursor Solution ◽  
Milling Process ◽  
Citrate Method ◽  
Nano Powder ◽  
Average Grain Size

A citrate method to synthesize 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 nano-powder was studied. The stable gel was obtained by the control of the pH value and temperature of the precursor solution. The BNBT nano-powder was produced after calcining the xerogel at 600°C~800°C. The average grain size of the powder calcined at 700°C for 3 h is 50 nm, and the grain size of the ceramic sintered at 1080°C is 0.7 μm. The sintering temperature used is 100°C lower than the BNBT ceramic prepared by traditional method, but the electrical properties were comparable. In addition, it was found that the ball-milling process has important effect on the morphology of the ceramics and the orientation crystals were eliminated due to the disintegration of agglomerates during milling.

The Electrical Properties of BCZT Lead-Free Ceramics Induced by BaZrO3 Seeds

2016 ◽  
Vol 690 ◽  
pp. 114-119
Author(s):  
Piewpan Parjansri ◽  
Manlika Kamnoy ◽  
Uraiwan Intatha ◽  
Sukum Eitssayeam ◽  
Tawee Tunkasiri
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Perovskite Phase ◽  
Nano Particle ◽  
Sintered Ceramic ◽  
Voltage Coefficient ◽  
Lead Free Ceramics ◽  
Seed Content ◽  
Pure Perovskite Phase ◽  
Average Grain Size

Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramics were produced by using the seed-induced method. The nano-particle BZ (BaZrO3) seeds were mixed with BaCO3, CaCO3, ZrO2 and TiO2 powder for preparing by the mixed oxide method. The XRD results indicated that all powder and sintered ceramic samples showed a pure perovskite phase with coexistence between rhombohedral and tetragonal phase. As the BZ seed content increased, the density of ceramics tended to decrease from 5.61 g/cm3 to 5.37 g/cm3. The average grain size of the ceramics was in the range of 12.15 -13.50 mm. The dielectric loss (tand) was less than 0.03 for all samples at room temperature (at 1 kHz). Other electrical properties, including dielectric constant (εr), remnant polarization (Pr), and piezoelectric charge coefficient (d33) values decreased with increasing BZ seed doping with relates to the decreasing grain size and density of BCZT ceramics. However, the values of coercive field (Ec) decreased and piezoelectric voltage coefficient (g33) increased with BZ seed doping.

Colloidal processing and mechanical properties of silicon carbide with alumina

1997 ◽  
Vol 12 (11) ◽  
pp. 3146-3157 ◽  
Author(s):  
Yoshihiro Hirata ◽  
Kouji Hidaka ◽  
Hiroaki Matsumura ◽  
Yasuo Fukushige ◽  
Soichiro Sameshima
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Size Dependence ◽  
Theoretical Density ◽  
Aspect Ratios ◽  
Median Size ◽  
Average Grain Size ◽  
Sintering Mechanisms ◽  
Ph Range

Submicrometer-sized SiC coated with SiO2 of 0.4–1.8 wt.% and α–Al2O3 powder of median size 0.2 μm were mixed in aqueous solutions in the pH range 3.0–10.0. The SiC/Al2O3 (4.3–6.9 wt. %) powders were consolidated by filtration through gypsum molds and hot-pressed at 1600°–2040 °C under a pressure of 39 MPa. These compacts were densified to near the theoretical density at 1700°–1800 °C. The sintering mechanisms are discussed based on the analysis of shrinkage curves of SiC/Al2O3 compacts during hot-pressing. The equiaxed SiC grains grew with low aspect ratios below 1800 °C and changed to plate-like grains at 1900 °C. The fracture toughness of SiC as a function of average grain size reached a maximum of 5 Mpa · m0.5 at 2.5 μm grains of low aspect ratios of 1–2. The flexural strengths at room temperature were 230–430 MPa in the SiC above 98% of the theoretical density and showed a similar grain size dependence.

Influence of CeO2-Doping on the Electrical Properties of ZnO-Bi2O3-Based Varistor Ceramics

2016 ◽  
Vol 697 ◽  
pp. 262-266
Author(s):  
Zhan Chuan Cao ◽  
Liao Ying Zheng ◽  
Li Hong Cheng ◽  
Tian Tian ◽  
Guo Rong Li
Keyword(s):  
Grain Size ◽  
Phase Composition ◽  
Detection Limit ◽  
Electrical Properties ◽  
Barrier Height ◽  
Nonlinear Coefficient ◽  
Donor Concentration ◽  
Average Grain Size ◽  
Doped Zno ◽  
Density Of Interface States

The microstructure and electrical properties of CeO2-doped ZnO-Bi2O3-based varistors were investigated for different amounts of the dopant. The phase composition of CeO2-doped samples was similar to the undoped samples. Ce mainly segregated at the grain boundaries within the EDS detection limit. The average grain size decreased from 7.3 to 6.7 μm and the breakdown voltage increased from 438 to 501 V/mm when the content of CeO2 ranged from 0 to 0.2 mol%. The nonlinear coefficient increased from 38 to 51 when the content of CeO2 increased from 0 to 0.1 mol%., but the further doping caused it to decrease up to 44 at 0.2mol%. The leakage current decreased from 1 to 0.4 μA/cm2 when the content of CeO2 ranged from 0 to 0.1 mol%. Then it increased to 0.7 μA/cm2 at 0.2 mol%. The density of interface states, the barrier height and the donor concentration increased when the content of CeO2 ranged from 0 to 0.1 mol%, but decreased at 0.2 mol%. Hence, when the content ranges from 0 to 0.1 mol%, CeO2 acts as a donor and can improve the electrical properties.

Effects of Different Antimony Dopants on ZnO-V2O5 Based Varistor Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 735-738
Author(s):  
Ming Zhao ◽  
Wei Min Wang ◽  
Xiang Chun Liu ◽  
Chang Sheng Tian
Keyword(s):  
Grain Size ◽  
Phase Composition ◽  
Electrical Properties ◽  
Gradual Increase ◽  
Electrical Characteristics ◽  
Structural Variations ◽  
Homogeneous Microstructure ◽  
Antimony Doping ◽  
Average Grain Size ◽  
Ultimate Cause

The effects of pre-synthesized V2O5/Sb2O3 compound, SbVO4 and Sb2O3 on the microstructure and electrical properties of ZnO-V2O5 based varistor ceramics have been studied. The general homogeneous microstructure and phase composition of the ceramics have not been influenced by the antimony doping form changes, except for the gradual decrease in average grain size and the increase in spinel formation within the ceramics. The ultimate cause of micro-structural variations with the antimony doping form changes seems to have been the gradual increase in Sb3+ concentration within the ceramics. This change in micro-composition, together with the changes in microstructure, caused the electrical characteristics of the ceramics to vary. The pre-synthesized V2O5/Sb2O3 compound is the most effective antimony dopant in term of its effect on the ceramics.

scholarly journals Crystal Diffraction Techniques Were Used to Investigate the Structural Properties of Some Aluminum Alloys.

2022 ◽  
Vol 961 (1) ◽  
pp. 012018
Author(s):  
Sukaina Iskandar Yusuf ◽  
Mohammed Muhana Meteab ◽  
Abdulkader Ahmed Annaz
Keyword(s):  
Grain Size ◽  
Aluminum Alloys ◽  
Structural Properties ◽  
Spherical Shape ◽  
Sem Analysis ◽  
Theoretical Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Grain Size ◽  
Radiation Shields

Abstract Due to the importance of these alloys in the manufacture of aircraft, coatings, radiation shields, and electronic circuits, the study’s objectives include investigating previously unstudied structural properties of some aluminum alloys, alloy A (Al-Zn-Mg-Ti) and alloy B (Al-Zn-Mg-Mn) were prepared using the casting method, and their structural properties were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques (granular size and theoretical density). The results of analyzing the X-ray diffraction data and determining the phases formed on the two alloys after matching them with the international standard cards (JCPDS) revealed that it is polycrystalline, with structures (cubic and hexagonal) on alloy A and structures (cube, hexagonal, and anorthic) on alloy B. The results revealed that the average grain size estimated by the Debye-Scherer method is less than that estimated by the Williamson-Hall method, and that the grain size of alloy A is less than that of alloy B due to the presence of titanium in alloy A’s composition, which works to reduce particle size. The theoretical density of Alloy A and B that was used in X-ray diffraction was calculated. SEM analysis of the spherical shape of the grains on the surfaces of alloys A and B revealed that the average grain size on the surface of alloy A is smaller than on the surface of alloy B, which is consistent with the results of XRD analyses.

STRUCTURAL AND ELECTRICAL PROPERTIES OF Nb5+ SUBSTITUTED PZT CERAMICS

2005 ◽  
Vol 19 (30) ◽  
pp. 1783-1791 ◽  
Author(s):  
O. P. THAKUR ◽  
CHANDRA PRAKASH
Keyword(s):  
Grain Size ◽  
Transition Temperature ◽  
Electrical Properties ◽  
Raw Materials ◽  
Pzt Ceramics ◽  
X Ray ◽  
Niobium Doping ◽  
Average Grain Size ◽  
Structural And Electrical Properties ◽  
Sample Structure

The effect of niobium doping on the structure and electrical properties with the following compositions Pb ( Zr 0.52 Ti 0.48)1-5X/4 Nb X O 3 with 0<x<0.025 was investigated. The materials were prepared by the usual ceramic technique using high purity raw materials. Disc-shaped samples of each compositions were sintered at 1250°C for 3 hours. The sample structure was determined by X-ray diffractometry. The average grain size, the maximum dielectric permittivity and the remnant polarization first increases up to x = 0.005 concentration of Nb 5+ and then decreases with higher concentration of niobium, while the coercive field does not show any variation. The transition temperature decreases with the increase in niobium concentration.

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