scholarly journals Sonochemical Synthesis of Nano-Structured Hydroxyapatite with unique morphologies and Evaluation of Sintering Kinetics

2015 ◽  
Vol 11 (8) ◽  
pp. 3789-3797 ◽  
Author(s):  
Roy Johnson ◽  
Papiya Biswas ◽  
Bandhakavi Lakshmi Sindhura ◽  
Chandhana Muraleedharan Nair ◽  
Pandu Ramavath ◽  
...  
Keyword(s):  
Ceramic Powder ◽  
Precursor Solution ◽  
Average Diameter ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Strong Function ◽  
Glass Substrates ◽  
Xrd Patterns ◽  
Dilatometric Studies ◽  
Activation Energy Of Sintering

Phase pure hydroxyapatite (HAp) (Ca10(PO4)6(OH)2) ceramic powder was synthesized from the stoichiometric solution of calcium hydroxide and orthophosphoric acid employing  sonochemical technique. Crystallinity of the HAp powder is found to be a strong function of amplitude of the ultrasound generator as revealed by XRD patterns and FTIR recorded on the samples prepared using varying amplitudes. Calcination of HAp powder beyond 700°C has resulted in the initiation of sintering as is evident from dilatometric studies and are complimented by the SEM micrographs. Activation energy of sintering of hydroxyapatite pellets using dilatometric sintering kinetic analysis has estimated to be 668±45kJ/mole corresponding to grain boundary diffusion as the prominent mass transport mechanism. Samples exhibited a density of 3.12g/cm3, close to theoretical density (~ 99 %) at the peak temperature of 1200°C. Studies on AC conductivity of the sintered samples exhibited relatively high room temperature conductivity of 5.07x10-8 S/m and a rising trend with temperature probably due to mobility of H+ and OH- ions. Attempts were also made to produce HAp nanorods sonochemically on the ordinary glass substrates immersed in the stoichiometric HAp precursor solution. Surface topographic images of the HAp deposited on glass substrate exhibited nanorods almost individually separated with an average diameter of 50 nm and 200 nm in length providing a process for synthesizing nano-structured HAp with simultaneous deposition exhibiting unique morphologies.

The Role of Formic Acid as Secondary Dopant and Solvent for Poly(O-Toluidine) Intrinsically Doped with Camphor Sulfonic Acid

2021 ◽  
Vol 1039 ◽  
pp. 260-268
Author(s):  
Kahtan A. Mohammed ◽  
Kareema M. Ziadan ◽  
Alaa S. Al-Kabbi ◽  
Dalael Saad Abdulzahr ◽  
Hawraa Kareem Judi ◽  
...  
Keyword(s):  
Formic Acid ◽  
Sulfonic Acid ◽  
Room Temperature ◽  
Substrate Surface ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Camphor Sulfonic Acid ◽  
Chemical Polymerization ◽  
Glass Substrates

The role of formic acid as Secondary Dopant for Poly (O-toluidine) Intrinsically Doped with Camphor Sulfonic-Acid (POT-CSA) nanoparticles were prepared by chemical polymerization had been studied. Spin coating and casting method have been used to deposit good adhesion and uniform thin films of (POT-CSA) on a glass substrates at room temperature. the properties of (POT-CSA) nanoparticles which examined by FTIR, SEM, AFM, XRD, I-V characteristics and UV-VIS. FTIR studies show the several bending and stretching modes of POT. XRD examination demonstrated that NPS. has a semi-crystalline pattern . The synthesized film well covered by the nanoparticles over the entire substrate surface, exhibits uniform, porous, and spherical granular surface morphology, A narrow size distribution is observed and the average size of particles about 80 nm. The band gap (Eg) has been determined which is equal to 3.1 ev. The room temperature conductivity of POT-CSA was 3 * 10-1 S.cm-1,which increases with increasing temperature. Electrical conductivity enhances up to three order after the secondary doping process. Keywords: POT-Chemical polymerization-Conducting polymer-SEM-AFM

scholarly journals Old Donors for New Molecular Conductors: Combining TMTSF and BEDT-TTF with Anionic (TaF6)1−x/(PF6)x Alloys

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 386
Author(s):  
Magali Allain ◽  
Cécile Mézière ◽  
Pascale Auban-Senzier ◽  
Narcis Avarvari
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Density Wave ◽  
Spin Density Wave ◽  
Orthorhombic Phase ◽  
Molecular Conductors ◽  
Bechgaard Salts ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Resistivity Measurements

Tetramethyl-tetraselenafulvalene (TMTSF) and bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) are flagship precursors in the field of molecular (super)conductors. The electrocrystallization of these donors in the presence of (n-Bu4N)TaF6 or mixtures of (n-Bu4N)TaF6 and (n-Bu4N)PF6 provided Bechgaard salts formulated as (TMTSF)2(TaF6)0.84(PF6)0.16, (TMTSF)2(TaF6)0.56(PF6)0.44, (TMTSF)2(TaF6)0.44(PF6)0.56 and (TMTSF)2(TaF6)0.12(PF6)0.88, together with the monoclinic and orthorhombic phases δm-(BEDT-TTF)2(TaF6)0.94(PF6)0.06 and δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57, respectively. The use of BEDT-TTF and a mixture of (n-Bu4N)TaF6/TaF5 afforded the 1:1 phase (BEDT-TTF)2(TaF6)2·CH2Cl2. The precise Ta/P ratio in the alloys has been determined by an accurate single crystal X-ray data analysis and was corroborated with solution 19F NMR measurements. In the previously unknown crystalline phase (BEDT-TTF)2(TaF6)2·CH2Cl2 the donors organize in dimers interacting laterally yet no organic-inorganic segregation is observed. Single crystal resistivity measurements on the TMTSF based materials show typical behavior of the Bechgaard phases with room temperature conductivity σ ≈ 100 S/cm and localization below 12 K indicative of a spin density wave transition. The orthorhombic phase δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57 is semiconducting with the room temperature conductivity estimated to be σ ≈ 0.16–0.5 S/cm while the compound (BEDT-TTF)2(TaF6)2·CH2Cl2 is also a semiconductor, yet with a much lower room temperature conductivity value of 0.001 to 0.0025 S/cm, in agreement with the +1 oxidation state and strong dimerization of the donors.

scholarly journals Synthesis and Characterization of Lithium-Ion Conductive LATP-LaPO4 Composites Using La2O3 Nano-Powder

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3502
Author(s):  
Fangzhou Song ◽  
Masayoshi Uematsu ◽  
Takeshi Yabutsuka ◽  
Takeshi Yao ◽  
Shigeomi Takai
Keyword(s):  
Room Temperature ◽  
Conduction Mechanism ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Nano Powder ◽  
Powder Addition

LATP-based composite electrolytes were prepared by sintering the mixtures of LATP precursor and La2O3 nano-powder. Powder X-ray diffraction and scanning electron microscopy suggest that La2O3 can react with LATP during sintering to form fine LaPO4 particles that are dispersed in the LATP matrix. The room temperature conductivity initially increases with La2O3 nano-powder addition showing the maximum of 0.69 mS∙cm−1 at 6 wt.%, above which, conductivity decreases with the introduction of La2O3. The activation energy of conductivity is not largely varied with the La2O3 content, suggesting that the conduction mechanism is essentially preserved despite LaPO4 dispersion. In comparison with the previously reported LATP-LLTO system, although some unidentified impurity slightly reduces the conductivity maximum, the fine dispersion of LaPO4 particles can be achieved in the LATP–La2O3 system.

Structure and Conductivity of Iodine-Doped C60 Thin Films

1994 ◽  
Vol 359 ◽  
Author(s):  
Jun Chen ◽  
Haiyan Zhang ◽  
Baoqiong Chen ◽  
Shaoqi Peng ◽  
Ning Ke ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Room Temperature ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Thermally Activated ◽  
Order Of Magnitude

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.

Surface Modification of High Density Ceramic Powder for Increasing Suspension Capacity in Three-Dimensional Printing Application

2018 ◽  
Vol 936 ◽  
pp. 159-163 ◽  
Author(s):  
Huang Jan Hsu ◽  
Shyh Yuan Lee ◽  
Shinn Liang Chang ◽  
Cho Pei Jiang
Keyword(s):  
Surface Modification ◽  
Ball Milling ◽  
Ceramic Powder ◽  
Three Dimensional ◽  
Treatment Protocol ◽  
Weight Ratio ◽  
Average Diameter ◽  
Zirconia Powder ◽  
Three Dimensional Printing ◽  
Promising Tool

Three-dimensional slurry printing is a promising tool for making ceramic object but it limits in high dense ceramic powder because of poor suspension capacity. This study uses zirconia powder with an average diameter of 2 μm because its density is 5.67 g/cm3. A treatment protocol is proposed to improve the suspension capacity of zirconia powder including the ball milling, surface modification and resin blending. Experimental results show that adding 1% of isostearyl titanate, a coupling agent, for surface modification can enhance the lipophilicity of zirconia powder. Mixing surface modification powder in resin with a weight ratio of 7:3 and carrying on ball milling with 100 RPM for 6 hours can obtain the diameter of powder less than 400 nm. As a result, the zirconia slurry can obtain good suspension capacity which is over 48 hours.

A Novel Approach to Nanoscale Materials Synthesis Using Industrial Laser Processing of Organosilazane Liquid Precursors

1990 ◽  
Vol 206 ◽  
Author(s):  
Tongsan D. Xiao ◽  
Peter R. Strutt ◽  
Kenneth E. Gonsalves
Keyword(s):  
Ceramic Powder ◽  
Average Diameter ◽  
Current Approach ◽  
Powder Materials ◽  
Materials Synthesis ◽  
Laser Plume ◽  
New Approach ◽  
Novel Approach ◽  
Liquid Precursors ◽  
Short Time

ABSTRACTA new approach has been developed for the synthesis of nanoscale ceramic powder materials from liquid organosilazane precursors. This technique, by exploiting fast kinetic chemical and physical reactions, makes it possible to synthesize significant quantities of material in a relatively short time. In the current approach aerosols of a silazane monomer, (CH3SiHNH)n, (n = 3 or 4), of mol. wt. 280–320, are injected into the beam of a cw industrial CO2 laser to obtain nanoscale ceramic powders. Injection of the aerosol into the laser-beam results in a high-temperature plume. Rapid condensation of the molecular precursor species emerging from the laser plume results in the formation of preceramic polymer particles, with an average diameter of 62 nm. One attractive feature of this process is that 70 wt.% of the liquid precursor is converted into nanoscale powders. Another feature is that only a further 10 wt.% loss occurs during post thermal treatment to form the end-product.

A comparative study of Li10.35Ge1.35P1.65S12 and Li10.5Ge1.5P1.5S12 superionic conductors

2020 ◽  
Vol 13 (06) ◽  
pp. 2050031
Author(s):  
Yue Jiang ◽  
Zhiwei Hu ◽  
Ming’en Ling ◽  
Xiaohong Zhu
Keyword(s):  
Ionic Conductivity ◽  
Room Temperature ◽  
Ionic Conductivities ◽  
Lithium Ion ◽  
Lattice Parameter ◽  
Superionic Conductors ◽  
Chemical Compositions ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Ion Conductor

Since the lithium-ion conductor Li[Formula: see text]GeP2S[Formula: see text] (LGPS) with a super high room-temperature conductivity of 12[Formula: see text]mS/cm was first reported in 2011, sulfide-type solid electrolytes have been paid much attention. It was suggested by Kwon et al. [J. Mater. Chem. A 3, 438 (2015)] that some excess lithium ions in LGPS, namely, Li[Formula: see text]Ge[Formula: see text] P[Formula: see text]S[Formula: see text], could further improve their ionic conductivities, and the highest conductivity of 14.2[Formula: see text]mS/cm was obtained at [Formula: see text] though a larger lattice parameter that occurred at [Formula: see text]. In this study, we focus on these two different chemical compositions of LGPS with [Formula: see text] and [Formula: see text], respectively. Both samples were prepared using the same experimental process. Their lattice parameter, microstructure and room-temperature ionic conductivity were compared in detail. The results show that the main phase is the tetragonal LGPS phase but with a nearly identical amount of orthorhombic LGPS phase coexisting in both samples. Bigger lattice parameters, larger grain sizes and higher ionic conductivities are simultaneously achieved in Li[Formula: see text]Ge[Formula: see text]P[Formula: see text]S[Formula: see text] ([Formula: see text]), exhibiting an ultrahigh room-temperature ionic conductivity of 18.8[Formula: see text]mS/cm.

Ion transport studies in PVA:NH4CH3COO gel polymer electrolytes

2020 ◽  
Vol 32 (2) ◽  
pp. 208-219
Author(s):  
CP Singh ◽  
PK Shukla ◽  
SL Agrawal
Keyword(s):  
Ionic Conductivity ◽  
Ion Transport ◽  
Salt Concentration ◽  
Polymer Electrolytes ◽  
Poly Vinyl Alcohol ◽  
Infrared Analysis ◽  
Gel Polymer Electrolytes ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Mobility Of Charge Carriers

Ion conducting gel polymer electrolytes (GPEs) are being intensively studied for their potential applications in various electrochemical devices. The poly(vinyl alcohol)-based GPE films containing ammonium acetate (NH4CH3COO) salt have been studied for various concentrations of salt. The gel electrolyte films (GPEs) have been prepared using solution casting technique. Structural characterization carried out using X-ray diffraction reveals an increase in the amorphous nature of the samples on increasing salt concentration up to 70 wt%. The complexation of polymer and salt has been studied by Fourier-transform infrared analysis. Ionic conductivity of the GPEs has been found to increase with salt concentration and reaches an optimum for an intermediate concentration. The room temperature conductivity isotherm exhibits a maximum in conductivity of 2.64 × 10−4 Scm−1 for 65 wt% salt concentration. The temperature dependence of ionic conductivity exhibits a combination of Arrhenius and Vogel–Tamman–Fulcher behavior. Ion transport in the electrolyte system has been explored using dielectric response of the material and the observed variation in conductivity is suitably correlated to the change in charge carrier concentration and mobility of charge carriers.

Comparison of Doping of Gey Si1-y:H (y>0.95) Films Deposited by Low Frequency PECVD at High (300°C) and Low (160°C) Temperatures

2012 ◽  
Vol 1426 ◽  
pp. 295-299
Author(s):  
Ismael Cosme ◽  
Andrey Kosarev ◽  
Francisco Temoltzi Avila ◽  
Adrian Itzmoyotl
Keyword(s):  
Activation Energy ◽  
Deposition Temperature ◽  
Solid Phase ◽  
Low Frequency ◽  
General Effect ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
High Deposition Temperature ◽  
B Doping ◽  
Low Deposition Temperature

ABSTRACTIn this work we present the results of comparative study n- and p-doping of Ge:H and Ge0.96Si0.04 :H films deposited by LF PECVD at high deposition temperature (HT) Td=300°C and low deposition temperature (LT) Td=160°C. The concentration of boron and phosphorus in solid phase was measured by means of SIMS technique. Such parameters as spectral dependence of absorption coefficient, room temperature conductivity σRT and activation energy Ea for both intrinsic and doped films were obtained. The doping range studied in gas phase was for boron [B]gas= 0 to 0.15% and for phosphorus [P]gas= 0 to 0.2%. In general effect of deposition temperature on P and B doping has been demonstrated. For LT films changes of [P]gas=0.04% to 0.22% resulted in more than 2 orders increasing conductivity and reducing activation energy from Ea=0.28 to 0.16 eV. HT films in the range of [P]gas=0.04% to 0.2% demonstrated saturation of conductivity. HT films showed continuous reducing Ea with increase of [P]gas. In the case of boron doping both HT and LT films had a minimum of conductivity at certain values of [B]gas=0.05% (LT films) and 0.04% (HT films) and related maximums of activation energy Ea(max) at the same doping with Ea(max)=0.47 eV for HT and Ea(max)=0.53 eV for LT films. It suggests a compensation of electron conductivity in un-doped films for low B doping. Further raising [B]gas leads to reducing Ea and the smallest Ea=0.27 eV was obtained at [B]gas=0.18% for HT films and Ea=0.33 eV at [B]gas=0.14% for LH films.

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