Effects of Sr and Mn-Doping on the Electrical Properties of CaBi4Ti4O15-Based Ceramics

Lead-free Sr-and Mn-doped Ca1-xSrxBi4Ti4O15, Ca1-yMnyBi4Ti4O15 bismuth layer piezoelectric ceramics have been prepared. The microstructure and electrical properties of the products were studied by XRD, SEM and Broadband LRC digital bridge. The obtained ceramics have Bi-layer perovskite phase. The dopings do not change the crystal phase of CaBi4Ti4O15. However, the doping amounts affect the size of crystal grain and porosity of the final products. The appropriate amounts of dopings for obtaining the highest dielectric constant and the lowest dielectric loss are determined. The prepared ceramics show the largest piezoelectric constant of 5.2~5.3 pC/N with the optimal Sr-and Mn-dopings.

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Influence of La2O3 Doping Amount on Properties of NBT-KBT-BT Lead-Free Piezoelectric Ceramics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.43.614 ◽

2010 ◽

Vol 43 ◽

pp. 614-618

Author(s):

Xin You Huang ◽

Chun Hua Gao ◽

Min Xian Wei ◽

Zhi Gang Chen

Keyword(s):

Dielectric Constant ◽

Dielectric Loss ◽

Perovskite Phase ◽

Piezoelectric Ceramics ◽

Lead Free ◽

Doping Amount ◽

Sem Images ◽

Solid State Method ◽

Piezoelectric Strain ◽

Piezoelectric Strain Constant

0.85(Na0.5Bi0.5)TiO3-0.144(K0.5Bi0.5)TiO3-0.006BaTiO3(NBT-KBT-BT) lead-free piezo -electric ceramics were prepared using conventional solid state method. The influence of La2O3 doping amount on the crystal phase, surface microstructure and properties of the NBT-KBT-BT lead free piezoelectric ceramics were investigated using X-ray diffraction(XRD), Scanning electron microscopy(SEM) and other analytical methods. The results show that La2O3 has diffused into the lattice of NBT-KBT-BT ceramics. Consequently, a pure perovskite phase is formed. SEM images show that the microstructure of the ceramics is changed with the addition of a small amount of La2O3, La2O3 doping can make grain growing. The piezoelectric strain constant(d33) starts increasing and then decreasing, the dielectric constant(εT33/ε0) increases continuously and the dielectric loss(tanδ) starts increasing and then decreasing and then increasing when La2O3 doping amount increases. When the doping amount of La2O3 is 0.4wt.% and the sintering temperature is 1160°C, the NBT-KBT-BT piezoelectric ceramics with good comprehensive properties can be obtained. Its piezoelectric strain constant(d33), dielectric constant(εT33/ε0), and dielectric loss(tanδ) are 151pC/N, 1543 and 4.2%, respectively.

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Dielectric and Piezoelectric Properties of Lead Free (1-x-y)Na1/2Bi1/2TiO3-xBaTiO3-yBiFeO3 Piezoelectric Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.492.194 ◽

2011 ◽

Vol 492 ◽

pp. 194-197 ◽

Cited By ~ 1

Author(s):

Yue Fang Wang ◽

Xiu Jie Yi ◽

Wei Pan ◽

Guo Zhong Zang ◽

Juan Du

Keyword(s):

Electrical Properties ◽

Dielectric Loss ◽

Phase Structure ◽

Perovskite Structure ◽

Piezoelectric Properties ◽

Piezoelectric Ceramics ◽

Lead Free ◽

Compositional Dependence ◽

Pure Perovskite Structure ◽

Dielectric And Piezoelectric Properties

Lead-free (1-x-y)Na1/2Bi1/2TiO3-xBaTiO3-yBiFeO3 ceramics were synthesized by ordinary sintering technique. The compositional dependence of phase structure and electrical properties of the ceramics was systematically investigated. All samples possessed pure perovskite structure. The dielectric and piezoelectric properties of ceramics were investigated with the amount of different BiFeO3 substitutions. The addition of BiFeO3 can not only decrease Ec and Pr but also lead to a significant degradation of the dielectric loss tanδ.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.184 ◽

2007 ◽

Vol 336-338 ◽

pp. 184-187 ◽

Cited By ~ 3

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.

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Electrical Properties and Polarization Reversal in (Li,Na)NbO3 Lead-Free Piezoelectric Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.485.69 ◽

2011 ◽

Vol 485 ◽

pp. 69-72 ◽

Cited By ~ 1

Author(s):

Takayuki Ohashi ◽

Rintaro Aoyagi ◽

Masaki Maeda ◽

Makoto Iwata

Keyword(s):

Dielectric Constant ◽

Electrical Properties ◽

Frequency Dependence ◽

Piezoelectric Ceramics ◽

Polarization Switching ◽

Coupling Factor ◽

The Other ◽

Lead Free ◽

Polarization Reversal ◽

Other Hand

In this study, the relationships between the electrical properties and polarization switching of lead-free (Li0.06Na0.94)NbO3 (LNN6) ceramics were investigated. The electrical properties of stoichiometric LNN6 did not change with polarization switching. On the other hand, the frequency dependence of the impedance of Na-deficient LNN decreased with polarization switching, and the coupling factor kp, the piezoelecric constant d33 and the dielectric constant ε33T/ε0 decreased with polarization switching. Moreover, the dielectric curve of Na-deficient LNN6 after 10 switchings showed peaks at approximately 330, 400 and 500 °C

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KNN-BF Lead-Free Piezoelectric Ceramics Synthesized by Sol-Gel Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.740.3 ◽

2015 ◽

Vol 740 ◽

pp. 3-6

Author(s):

Guo Yuan Cheng ◽

Xing Hua Fu ◽

Xin Jin ◽

Wen Hong Tao ◽

Yu Qin Qiang

Keyword(s):

Comparative Analysis ◽

Citric Acid ◽

Dielectric Loss ◽

Sintering Temperature ◽

Sol Gel ◽

Piezoelectric Ceramics ◽

Lead Free ◽

Gel Method ◽

Sol Gel Method ◽

Metal Chelator

KNN-BF piezoelectric ceramics synthesized by sol-gel method in this experiment. By controlling bismuth and iron content in the system to study effects of them. We selected citric acid as metal chelator and ethylene glycol as esterification agent. PH maintained 5-6 during preparation of the sol. Sintering temperature of ceramic selected 1100°C. Preparation ceramics under these conditions and comparative analysis, the structure of ceramics is single perovskite and shap of crystals are square block. With the increase of x, properties of ceramics firstly increases and then decreases: d33, εr, Qm, Kpreaching the maximum, values of them were 136pC/N, 630(f =1KHz), 212, 0.41 respectively; dielectric loss to minimum is 0.07(f =1KHz); at this point, ceramics had best performance.

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Effect of Treatment Process on the Structure and Properties of Sr0.48Ba0.24Ca0.28TiO3-Based Varistor Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.775 ◽

2007 ◽

Vol 336-338 ◽

pp. 775-778

Author(s):

Yu Xing Xu ◽

Zi Long Tang ◽

Zhong Tai Zhang ◽

Li Hai Xu

Keyword(s):

Dielectric Constant ◽

Electrical Properties ◽

Dielectric Loss ◽

Treatment Process ◽

Oxidation Temperature ◽

Structure And Properties ◽

Defect Reactions ◽

Effect Of Treatment

Sr0.48Ba0.24Ca0.28TiO3-based varistor ceramics with an excellent capacitor-varistor multifunctional characteristics (V1mA = 11 ~ 49 ν.mm-1, α = 6.1 ~ 11.3, ε r max=3.5×105, tanδmin = 5%) were prepared using conventional solid method. The effect of oxidation temperature and time on structure and electrical properties were investigated. The results show that with increasing the oxidation temperature from 800°C to 900°C, the varistor voltage V1mA and non-linearity coefficient α defining varistor characteristics increase linearly, while the dielectric constant ε r and dielectric loss tanδ decrease linearly. There exists an optimum α value when the specimens were oxidized at 850°C for 3h. This behavior was explained through various defect reactions of dopants.

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