Effects of Temperature and Concentration on the Nano-Sized Hydroxyapatite Whisker Prepared by Chemical Precipitation Method

2007 ◽  
Vol 353-358 ◽  
pp. 2191-2194
Author(s):  
Yun Qiang Bai ◽  
Mu Sen Li ◽  
Yu Peng Lu ◽  
Ning Cao
Keyword(s):  
Heat Treatment ◽  
Raw Materials ◽  
Chemical Precipitation ◽  
Strength Test ◽  
Precipitation Method ◽  
Test Results ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Synthetic Temperature ◽  
Effects Of Temperature

Chemical precipitation is a popular method for the preparation of hydroxyapatite(Ca10 (PO4)6 (OH)2, HA) because of its simple operation. In this work, nano-sized HA whiskers were synthesized at various synthetic temperatures and concentration by chemical precipitation with Ca (NO3) 2·4H2O and (NH4) 2HPO4 as raw materials. Heat treatment was carried out after they were synthesized. The HA powders were analyzed by using X-ray diffraction (XRD), transmission electron microscope (TEM) and strength test in order to find the favorable growing condition for HA whiskers. The results show that the HA prepared at different synthetic temperatures show no impurity diffraction peak, indicating that they have a high purity. Prior to heat treatment, the crystallinity and length/diameter ratio of the HA whiskers become larger with the increasing of synthetic temperature. So a higher synthetic temperature can promote the growth of the HA whiskers. There is no obvious difference in crystallinity after the heat treatment. Besides, a lower reaction concentration can also promote the growth of HA whiskers. The strength test results show that the compressive strength of the HA prepared gets a maximum value at 50°C.

Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

scholarly journals Effect of Annealing on the ZnS Nanocrystals Prepared by Chemical Precipitation Method

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Nadana Shanmugam ◽  
Shanmugam Cholan ◽  
Natesan Kannadasan ◽  
Kannadasan Sathishkumar ◽  
G. Viruthagiri
Keyword(s):  
Chemical Precipitation ◽  
Chemical Precipitation Method ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Atomic Force ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Uv Visible ◽  
Dta Curves

Nanocrystals of ZnS have been synthesized through simple chemical precipitation method using thiourea as sulphur source. The synthesized products were annealed at different temperatures in the range of 200–800∘C. The as-synthesized and annealed samples were characterized by X-ray diffraction (XRD), UV-Visible absorption (UV-Vis), and room temperature photoluminescence (PL) measurements. The morphological features of ZnS annealed at 200 and 500∘C were studied by atomic force microscope (AFM) and transmission electron microscope (TEM) techniques. The phase transformation of ZnS and formation of ZnO were confirmed by thermogravimetric (TG) and differential thermal analysis (DTA) curves.

Synthesis and Characterization of γ-Al2O3 Nanowires by a Surfactant Assisted Precipitation Method

2014 ◽  
Vol 602-603 ◽  
pp. 93-96 ◽  
Author(s):  
Fan Cheng Meng ◽  
Cheng Liu ◽  
Xiao Lei Zhang ◽  
Hai Shen Ren ◽  
Tie Kun Jia
Keyword(s):  
Raw Materials ◽  
Sodium Aluminate ◽  
Precipitation Method ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Structure Directing Agent ◽  
Ctab Concentration ◽  
Transmission Electron ◽  
Cetyltrimethyl Ammonium ◽  
Surfactant Assisted

In this study, the γ-Al2O3 nanowires were prepared by a simple surfactant assisted precipitation method using the cetyltrimethyl ammonium bromide (CTAB) as a structure-directing agent (SDAs). Homemade sodium aluminate (NaAlO2) and H2O2 were used as raw materials. The influences of CTAB concentration and calcination temperature on the morphology of product were discussed. The obtained samples were investigated using transmission electron microscopy, X-ray diffraction analysis and TG-DSC. In the end, a possible formation mechanism of wire-like γ-Al2O3 is proposed.

Synthesis of RePO4 (Re=La, Nd, Pr, or Y) Nanowires by Chemical Precipitation in Nanochannels

2011 ◽  
Vol 181-182 ◽  
pp. 495-500 ◽  
Author(s):  
Cheng Mu ◽  
Jun Hui He
Keyword(s):  
Rare Earth ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Aao Template ◽  
Sem Images ◽  
Transmission Electron ◽  
Rare Earth Phosphate ◽  
Xrd Patterns ◽  
Uniform Diameter

Monodisperse nanowires of rare earth phosphates were synthesized by chemical precipitation method using anodic aluminum oxide (AAO) template. Scanning electron microscope (SEM) images indicated that rare earth phosphate nanowires are parallelly arranged in AAO template, all of which are in uniform diameter of about 50 nm. X-ray diffraction (XRD) patterns and high magnification transmission electron microscopy (HRTEM) images showed that the nanowires were polycrystal structure.

Fluorescence Enhancement of ZnS Nanocrystals via Ultraviolet Irradiation

2014 ◽  
Vol 556-562 ◽  
pp. 27-31
Author(s):  
Ling Ling Peng ◽  
Bi Tao Liu ◽  
Tao Han
Keyword(s):  
Ultraviolet Irradiation ◽  
Surface Defects ◽  
Irradiation Time ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Photoluminescence Intensity ◽  
X Ray Diffraction ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Zns Nanocrystals

ZnS nanocrystals were prepared via chemical precipitation method and characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) and photoluminescence (PL) spectra. The results indicated that the ZnS nanocrystals have cubic zinc blende structure and diameter is 3.68 nm as demonstrated by XRD. The morphology of nanocrystals is spherical measured by TEM which shows the similar particle size. The photoluminescence spectrum peaking at about 424 nm was due mostly to the trap-state emission, and a satellite peak at 480nm ascribed to the dangling bond of S in the surface of ZnS nanocrystals. The emission intensity of ZnS was enhanced after ultraviolet irradiation, the enhancement of the Photoluminescence intensity was due to the elimination of the surface defects after ultraviolet irradiation, for the growth of the coated shell on ZnS nonacrystals, the Photoluminescence intensity was increased as ultraviolet irradiation time growth, finally tends to be stable for the surface state of nanocrystals steady.

scholarly journals Synthesis and characterization of ZnTe nanoparticles

2016 ◽  
Vol 17 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Sujan Dhungana ◽  
Bhoj Raj Paudel ◽  
Surendra K. Gautam
Keyword(s):  
Particle Size ◽  
Field Effect Transistors ◽  
Average Particle Size ◽  
Precursor Solution ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Zinc Compounds ◽  
Transmission Electron

In this work, we report the ZnTe semiconductor nanoparticles (NPs) prepared by aqueous chemical precipitation method using the tellurium precursor solution with different zinc compounds. Three batches of ZnTe NPs were synthesized to study the effect of dilution on the size and phase purity of ZnTe. The influence of source compounds and concentrations of the size and structure of NPs were studied. ZnTe NPs have great applications as field-effect transistors and photodetectors. The existing controversy regarding the crystalline structure of ZnTe NPs, whether it is cubic or hexagonal, has been resolved using X-ray Diffraction (XRD) data. The ZnTe NPs possess cubic structure, which is also confirmed by Electron Diffraction (ED) pattern. The average particle size determined from XRD data with the help of Debye-Scherrer equation is about 6 nm. The particle size can be further verified by Transmission Electron Microscopy (TEM) studies.  

Effect of Heat Treatment on the Phase Transformation from SnS to Pure SnS2

2013 ◽  
Vol 829 ◽  
pp. 141-146
Author(s):  
Rahim Lotfi Orimi ◽  
Seyed Javad Mirdeylami
Keyword(s):  
Heat Treatment ◽  
Emission Spectra ◽  
Blue Shift ◽  
Chemical Precipitation ◽  
Treatment Temperature ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Absorption Studies ◽  
Absorbance Spectra

SnS2nanoparticles were prepared by heat treatment of SnS nanoparticles at 300 °C under N2atmosphere for 1hour. SnS nanoparticles have been synthesized by chemical precipitation method. As synthesized SnS nanoparticles, for determining the optimal temperature, were heated at various temperatures; 100, 150, 200, 250 and 300 °C N2atmosphere for 1hour. The products are characterized by X-ray diffraction (XRD) , ultraviolet visible (UV-vis) absorbance spectra and photoluminescence (PL). XRD and optical absorption studies show an increase in particle size with increasing heat treatment temperature from 100 to 200 °C . However, a large decrease in the nanoparticle size along with transforming from SnS to SnS2 is observed at 300 °C.In addition, the optical properties of al samples , including both UV-vis absorption and emission spectra showed a blue shift as the particles size decreased.

scholarly journals Preparation and Characterization of Hydroxyapatite by the precipitation method and heat treatment

2020 ◽  
Vol 9 (6) ◽  
pp. e172963549
Author(s):  
Fellype Diorgennes Cordeiro Gomes ◽  
Julia Didier Pedrosa de Amorim ◽  
Girlaine Santos da Silva ◽  
Karina Carvalho de Souza ◽  
Aline Ferreira Pinto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tooth Enamel ◽  
Raw Materials ◽  
Calcium Nitrate ◽  
Structural Evolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Human Bones

Hydroxyapatite is a synthetic substance in the form of microspheres composed of calcium and phosphate, present in human bones and tooth enamel. The objective of the work was to synthesize hydroxyapatite, from the solution of calcium nitrate and diamonic phosphate by the method of precipitation and heat treatment, obtaining the hydroxyapatite in powder form. To study its structural evolution, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman spectroscopy were used. The results show that the hydroxyapatite nanocrystalline can be successfully produced by the precipitation technique from raw materials.

Synthesis and Luminescent Behavior of Mn(1-X)S:AX/ZnS Core/Shell Nanocrystals

2011 ◽  
Vol 335-336 ◽  
pp. 669-673
Author(s):  
Li Hua Li ◽  
Yong Jun Gu ◽  
Rui Shi Xie ◽  
Jian Guo Zhu
Keyword(s):  
Surface Passivation ◽  
Spherical Shape ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Nonradiative Recombination ◽  
X Ray Diffraction ◽  
Enhanced Photoluminescence ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Zns Nanocrystals

Mn(1-X)S:AX/ZnS (A: Er, Dy) nanocrystals were synthesized by chemical precipitation method. X-ray diffraction analysis show that Mn(1-X)S:AX/ZnS nanocrystals were zincblende structure. The high-resolution transmission electron microscope images indicated that Mn(1-X)S:AX/ZnS nanocrystals show a spherical shape, and their average grain size is about 4 nm. Photoluminescence spectra of Mn(1-X)S:AX/ZnS nanocrystals revealed that there existed several major emission bands, ～417 nm, ~509 nm, ~580 nm, ~617nm and ~680 nm. Mn(1-X)S:AX/ZnS nanocrystals exhibited enhanced luminescence properties compared with the pure Mn(1-X)S:AX nanocrystals. The enhanced photoluminescence properties of Mn(1-X)S:AX/ZnS nanocrystals should be attributed to the effective suppression of nonradiative recombination by the surface-passivation layer.

scholarly journals PHASE COMPOSITION AND CRYSTALLINITY OF HYDROXYAPATITE WITH VARIOUS HEAT TREATMENT TEMPERATURES

2018 ◽  
Vol 9 ◽  
pp. 87 ◽  
Author(s):  
Decky J Indrani ◽  
Bambang Soegijono ◽  
Wisnu A Adi ◽  
Neil Trout
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Phosphorous Acid ◽  
Chemical Precipitation ◽  
Hexagonal Structure ◽  
Treatment Temperature ◽  
Precipitation Method ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
Additional Phase

Objective: This study investigated effects of heat treatment on the crystallinity and phase composition of hydroxyapatites (HAs) of different heat treatment.Methods: HA powder was synthesized by the chemical precipitation method based on the reaction between the phosphorous acid and calcium hydroxide. Synthesized HA was divided into three groups for which each group was then given heat treatment at 100°C, 900°C, or 1300ºC. Phase identification, analyses and the crystallinity of the synthesized HAs were determined using the X-ray diffraction coupled with the Rietveld refinement.Results: The synthesized HAs with each heat treatment were identified as HA phase containing hexagonal structure. Those treated at 100°C or 900°C revealed with crystallinity of 48% and 68%, respectively, with no additional phase; whereas, those treated at 1300°C produced a crystallinity of 72% and contained dicalcium and tricalcium phosphates.Conclusion: The synthesized HAs treated at 100°C, 900°C, or 1300°C were HA phase with hexagonal structure. The variable crystallinity of the synthesized HAs yielded from different heat treatment temperature correspondingly determines different phase composition.

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