Tuning the mechanical and dielectric properties of zinc incorporated hydroxyapatite

2020 ◽  
Vol 16 ◽  
Author(s):  
Alliya Qamar ◽  
Rehana Zia ◽  
Madeeha Riaz
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Bone Growth ◽  
Healing Process ◽  
Secondary Phase ◽  
Chemical Precipitation ◽  
Hexagonal Structure ◽  
Precipitation Method ◽  
Low Frequencies ◽  
A Minor

Background: Hydroxyapatite is similar to bone mineral in chemical composition, has good biocompatibility with host tissue and bone. Objective: This work aims to tailor the mechanical and dielectric properties of hydroxyapatite with zinc sudstitution, to improve wearability of implant and accelerate the healing process. Method: Pure and zinc incorporated hydroxyapatite Ca10(PO4)6(OH)2 samples have been successfully prepared by means of the chemical precipitation method. Results: The results showed that hydroxyapatite(Hap) having hexagonal structure was the major phase identified in all the samples. It was found that secondary phase of β-tricalcium phosphate (β-TCP) formed due to addition of Zinc resulting in biphasic structure BCP (Hap + β-TCP). A minor phase of ZnO also formed for higher concentration of Zn (Zn ≥ 2mol%) doping. It was found that the Zn incorporation to Hap enhanced both mechanical and dielectric properties without altering the bioactive properties. The microhardness increased upto 0.87 GPa for Zn concentration equal to 1.5mol%, which is comparable to the human bone ~0.3 - 0.9 GPa. The dielectric properties evaluated in the study showed that 1.5 mol% Zn doped hydroxyapatite had highest dielectric constant. Higher values of dielectric constant at low frequencies signifies its importance in healing processes and bone growth due to polarization of the material under the influence of electric field. Conclusion: Sample Z1.5 having 1.5 mol% Zn doping showed the most optimized properties suitable for bone regeneration applications.

Size Dependent Dielectric Properties of TiO2 Nanoparticles

2020 ◽  
Vol 833 ◽  
pp. 147-151
Author(s):  
K.K. Anjali ◽  
A. Uma Maheswari ◽  
Manickam Sivakumar
Keyword(s):  
Dielectric Properties ◽  
Oxygen Vacancies ◽  
Surface Defects ◽  
Peak Shift ◽  
Chemical Precipitation ◽  
Space Charge Polarization ◽  
Precipitation Method ◽  
Bandgap Energy ◽  
Size Dependent ◽  
Mobility Of Charge Carriers

In this study, influence of nanoparticles size on optical and dielectric properties of TiO2 nanoparticles is investigated through thermal treatment of hydrous amorphous titania synthesized by chemical precipitation method at temperatures 300 °C and 600 °C. The average sizes of nanoparticles estimated respectively are ~ 8 nm and ~ 22 nm. Although the optical bandgap energy of both samples remains the same the Eg Raman mode observed at 144 cm-1 for bulk TiO2 is shifted to 150 cm-1 only for nanoparticles calcined at 300 °C. The shift is ascribed to the size as well as higher density of surface defects. Moreover, the presence of surface defects like oxygen vacancies which provide effective sites for catalytic reaction are confirmed by EPR and photoluminescence studies. The oxygen vacancies enhances space charge polarization and consequently results in higher dielectric constant. In addition, the peak shift of loss tangent which determines the mobility of charge carriers is found to be size dependent. Hence calcination temperature has significant influence on defect levels which in turn determine the optical and dielectric properties of TiO2 nanoparticles.

scholarly journals Investigation of AC-Measurements of Epoxy/Ferrite Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 492 ◽  
Author(s):  
Moustafa A. Darwish ◽  
Alex V. Trukhanov ◽  
Oleg S. Senatov ◽  
Alexander T. Morchenko ◽  
Samia A. Saafan ◽  
...  
Keyword(s):  
Experimental Data ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
High Frequency ◽  
Precipitation Method ◽  
Semiconductor Behavior ◽  
Ferrite Composites ◽  
Co Precipitation ◽  
Theoretical Results ◽  
Composite Samples

A pure ferrite and epoxy samples as well as the epoxy/ferrite composites with different 20 wt.%, 30 wt.%, 40 wt.%, and 50 wt.% weight ferrite contents have been prepared by the chemical co-precipitation method. AC-conductivity and dielectric properties such as the dielectric constant and dielectric loss of the prepared samples have been studied. The obtained results showed that the samples had a semiconductor behavior. The dielectric constant of the composites has been calculated theoretically using several models. For the composite sample that contains 20 wt.% of ferrites, these models give satisfactory compliance, while for the composite samples with a higher percentage of nanofillers, more than 30 wt.% theoretical results do not coincide with experimental data. The investigated polymer has very low conductivity, so this type of polymer can be useful for high-frequency applications, which can reduce the losses caused by eddy current. Thus, the prepared samples are promising materials for practical use as elements of microwave devices.

Synthesis and Characteristics of MgO Coated BST-Mg2TiO4 Composite Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1180-1183
Author(s):  
Qian Qian Jia ◽  
Hui Ming Ji ◽  
Shan Liu ◽  
Xiao Lei Li ◽  
Zheng Guo Jin
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Curie Temperature ◽  
Loss Tangent ◽  
Phase Shifters ◽  
Precipitation Method ◽  
Composite Ceramics ◽  
Low Dielectric ◽  
Dielectric Constant And Loss ◽  
Bst Ceramics

The (Ba, Sr)TiO3 (hereafter BST) ceramics are promising candidate for applying in tunable devices. MgO coated BST-Mg2TiO4 (BSTM-MT) composite ceramics were prepared to obtain the low dielectric constant, low dielectric loss, good dielectric constant temperature stability, and high tunability of BST ceramics. The Ba0.55Sr0.40Ca0.05TiO3 nanoparticles were coated with MgO using the precipitation method and then mixed with Mg2TiO4 powders to fabricate BSTM-MT composite ceramics. The morphologies, phases, elements, and dielectric properties of the sintered ceramics were investigated. The core-shell structure of BST powder wrapped with MgO was clearly observed from the TEM image. After sintered at 1100 °C for 2 h, the composite ceramics expressed dense microstructures from SEM images and two main phases BST and Mg2TiO4 were detected in the XRD patterns. The dielectric constant and loss tangent were both reduced after the coating. The reduced dielectric constant and loss tangent of BSTM-MT were 190, 0.0011 (2MHz), respectively. The ceramics exhibited the diffuse phase transition near the Curie temperature and the Curie temperature shifted from 10 °C to 5 °C after the coating. Since the continuous Ti-O bonds were disconnected with the MgO coating, the tunability was reduced to 15.14 % under a DC bias field of 1.1 kV/mm. The optimistic dielectric properties made it useful for the application of tunable capacitors and phase shifters.

Dielectric Properties of Li-Doped CaCu3Ti4O12 Ceramics

2011 ◽  
Vol 687 ◽  
pp. 251-256 ◽  
Author(s):  
Ying He ◽  
Huai Wu Zhang ◽  
Yuan Xun Li ◽  
Wei Wei Ling ◽  
Yun Yan Wang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Secondary Phase ◽  
Doping Amount ◽  
Spectroscopy Analysis ◽  
Low Dielectric ◽  
Tan Δ ◽  
High Dielectric ◽  
Impedance Spectroscopy Analysis

CaCu3Ti4O12 ceramics doped with 0-2.0 wt% Li2CO3 were prepared by the solid-state reaction, and their electric and dielectric properties were investigated. It is found that these ceramics had the properties of high dielectric constant and comparatively low dielectric loss. At the doping amount of 0.5 wt%, the dielectric constant is kept to be 105 with weak frequency dependence below 105 Hz, and its loss tangent (tan δ) is suppressed below 0.1 between 300 Hz-5 kHz (with the minimum value of 0.06 at 1 kHz from 218 K to 338 K). The impedance spectroscopy analysis confirms that the decrease of dielectric loss is mainly due to the increase of resistance in the grain boundary, which may be related to the influence of Ti4O7 secondary phase. Our result indicates that doping Li2CO3 is an efficient method to optimize the dielectric properties of CaCu3Ti4O12.

scholarly journals Influence of Mg Incorporation on Mechanical, Dielectric and Biological Properties of Hydroxyapatite Ceramic

2020 ◽  
Author(s):  
Alliya Qamar ◽  
Rehana Zia ◽  
Madeeha Riaz ◽  
Tousif Hussain ◽  
Safia Anjum
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Chemical Method ◽  
Secondary Phase ◽  
Biological Properties ◽  
Point Of View ◽  
Micro Hardness ◽  
Hydroxyapatite Ceramic ◽  
Third Phase ◽  
Two Phases

Abstract This research focused on the mechanical electrical and biological properties of magnesium doped (Mgx, x = 0.5 - 2.5 mol%) hydroxyapatite(Hap) using chemical method. It was observed that addition of magnesium produced the secondary phase (whitlockite) depended on the concentration of magnesium using the XRD, FTIR and Raman techniques. These two phases forming BCP(Biphasic) are beneficial from the implant point of view. The dielectric properties were measured as a function of frequency for different concentration of Mg. For 1.0 -2.0mol% doped Mg samples showed dielectric constant value within the range required for implant material. The bioactivity and However, beyond 2mol% of Mg third phase of magnesium oxide was also observed which enhanced the micro-hardness and bioactivity of specimen.

scholarly journals Magnetic and dielectric characteristics of Nd and Nd-Mg substituted strontium hexaferrite

2018 ◽  
Vol 4 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Basharat Want ◽  
Bilal Hamid Bhat
Keyword(s):  
Dielectric Constant ◽  
Grain Boundary ◽  
Secondary Phase ◽  
Xrd Analysis ◽  
Lattice Parameter ◽  
Anisotropy Constant ◽  
Systematic Investigation ◽  
Hexagonal Structure ◽  
Strontium Hexaferrite ◽  
Parameter Ratio

A systematic investigation on the phase formation, magnetic, dielectric and impedance properties of strontium hexaferrites doped with Nd and Nd-Mg was performed. All ferrite samples were prepared by the citrate-precursor method and characterized with a combination ofX-ray diffraction, Vibrating sample magnetometer and impedance analyser. XRD analysis confirms the magnetoplumbite structure with space groupp63/mmcwithout any secondary phase. The lattice parameter ratioc/alies in the range of 3.92 to 3.94 and shows that the prepared material exhibits M-type hexagonal structure. An increase in coercivity and a decrease in magnetization were observed for all the samples. Large value of coercivity suggests that these materials are useful in longitudinal recording media. Further, it was found that the value of magnetocrystalline anisotropy constantK1decreases with the substitution of Nd and Nd-Mg. Measurement of dielectric loss and dielectric constant were performed as a function of temperature and frequency. Dielectric constant and ac conductivity of Sr0.95Nd0.05Mg0.05Fe11.95O19is more as compared to Sr0.95Nd0.05Fe12O19and SrFe12O19for all frequencies. The value of grain boundary resistance (Rgb) of Sr0.95Nd0.05Fe12O19is less as compared to SrFe12O19and Sr0.95Nd0.05Mg0.05Fe11.95O19and vice versa trend is observed in the value of capacitance of the grain boundary (Cgb) and in the values of relaxation time (τgb).

HIGH PRESSURE EFFECTS ON ELECTRICAL RESISTIVITY AND DIELECTRIC PROPERTIES OF NANOCRYSTALLINE SnO2

2006 ◽  
Vol 05 (04n05) ◽  
pp. 471-477 ◽  
Author(s):  
P. THANGADURAI ◽  
A. CHANDRA BOSE ◽  
S. RAMASAMY ◽  
R. KESAVAMOORTHY ◽  
T. R. RAVINDRAN
Keyword(s):  
High Pressure ◽  
Dielectric Properties ◽  
Complex Impedance ◽  
Chemical Precipitation ◽  
Pressure Effects ◽  
Precipitation Method ◽  
Grain Sizes ◽  
Electrical And Dielectric Properties ◽  
High Pressure Effects

Rutile structured nanocrystalline tin oxide (nano- SnO 2) was prepared by chemical precipitation method with different grain sizes. Its electrical and dielectric properties were studied using complex impedance spectroscopy under different hydrostatic pressures. These studies showed a transition in nano- SnO 2 under high-pressure. The transition pressures obtained from both the resistivity and dielectric measurements agree with each other and increase considerably with decrease in grain size. In order to find whether the transition under pressure is structural related or not, in situ high pressure Raman spectroscopy was done up to 3.38 GPa at room temperature. No structural change was observed and the transition may be due to the co-operative phenomenon of the change in band gap and better connectivity between grain boundaries.

scholarly journals Dielectric Properties of Modified Lead Zirconate Titanate

2021 ◽  
Vol 16 (2) ◽  
Author(s):  
R.K. Sharma ◽  
Gunjan Purohit ◽  
D. K. Tyagi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
Dielectric Measurement ◽  
Low Frequencies ◽  
Loss Measurement ◽  
Zirconate Titanate ◽  
Paraelectric State

In this paper, the dielectric properties of modified i. e. alkali doped lead zirconate titanate Pb(Zr1- xTix)O3 has been studied. The composition Pb1-x (La1-zDz)x (Zry Ti1-y)1-x/4 O3;where x = 0.10, y = 0.70, z = 0.0, 0.1, 0.2, and 0.3, D= Na, K and Li has been prepared by conventional mixed oxide method at a temperature of 11000C. Dielectric constant and dielectric loss measurement of the sintered pellets has been measured. Dielectric measurement shows that the dielectric constant decreases with an increase in temperature. The results show that the dielectric loss is very small and decreases with frequency above 300°C. The increase in the dielectric constant observed at high temperatures and low frequencies is explained in the paraelectric state.

scholarly journals Effect of Zr4+ Content on Crystal Structure, Micromorphology and Dielectric Properties of Ba(Zrx Ti1-X)O3 Ceramics

2019 ◽  
Vol 3 (1) ◽  
Keyword(s):  
Crystal Structure ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Great Influence ◽  
Secondary Phase ◽  
Solid State Reaction Method ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

Ba(Zrx Ti1-x)O3 ceramics (X=1.5, 2.0, 2.5, 3.0) were prepared by solid-state reaction method. Effect of controlling the ratio of Zr/Ti on the crystal structure, micromorphology and dielectric properties of BZT ceramics. Their crystal structures, morphologies, and electric properties were respectively characterized using X-ray diffraction, scanning electron microscope and impedance analyzer. The X-ray diffraction patterns show that the zirconium titanate ceramic samples behave cubic phase structure and no secondary phase. The ratio of Zr/Ti has a great influence on the crystal structure, microstructure and dielectric properties. As the Zr4+ content increases, the lattice constant increases and the grain size decreases. The dielectric constant is the largest when the Zr content is 15%. As the Zr4+ content increases, the dielectric constant decreases gradually, and the Curie temperature moves toward the low temperature region.

Microstructure and Dielectric Properties of BaFe12O19 Hexaferrite Nanoparticles: Effect of Cobalt Addition and Calcination Temperature

2020 ◽  
Vol 13 (3) ◽  
pp. 211-219
Keyword(s):  
Dielectric Properties ◽  
Barium Hexaferrite ◽  
Hexagonal Structure ◽  
Dielectric Constants ◽  
Precipitation Method ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Tan Δ ◽  
Co Addition ◽  
Co Precipitation

Abstract: M-type Barium Hexaferrite (BaFe12O19) is a promising compound for technological applications because of its high permeability, high saturation magnetization and excellent dielectric properties. In this study, the microstructure and dielectric properties of CoxBaFe12O19Hexaferrite were investigated. The co-precipitation method was employed to prepare CoxBaFe12O19 nanoparticles, with x = 0, 0.04, 0.06 and 0.1 wt. %, at two different calcination temperatures (900oC and 950oC). The microstructure of the samples was examined through X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The hexagonal structure of the prepared samples was confirmed from XRD results. TEM images reveal the formation of agglomerated nanoparticles with different size distribution. The dielectric properties of the samples were studied through HIOKI 3532-50 LCR-Hi TESTER as a function of frequency (100 kHz–3MHz) and temperature (25 °C–500°C). The effects of Co addition, frequency and temperature on the dielectric constants (ɛʹ and ɛʹʹ), loss tangent (tan δ) and ac conductivity (σac) have been explained on the basis of hopping of electrons between Fe2+ and Fe3+ ions. Keywords: BaFe12O19 Hexaferrite, Co-precipitation method, XRD, Dielectric properties.

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