Microstructural Investigation of Fluoroapatite Hydrothermally Converted from Hydroxyapatite Synthesized from Crocodile Eggshell

2021 ◽  
Vol 32 ◽  
pp. 21-32
Author(s):  
Reedwan Bin Zafar Auniq ◽  
Weerapong Lerdrattranataywee ◽  
Upsorn Boonyang
Keyword(s):  
Crystal Size ◽  
Ph Value ◽  
Structure Evolution ◽  
Hexagonal Crystal ◽  
Microstructural Investigation ◽  
Unique Structure ◽  
Distinctive Morphology ◽  
Cubic Structure ◽  
Hexagonal Crystals ◽  
Dumbbell Structure

Fluoro/hydroxyapatite (FHAp) were prepared by hydrothermal at 150 °C for 24 hours with different of starting materials. The conversion of hydroxyapatite (HAp) and tricalcium phosphate to FHAp showed the rod-like shape with 200 nm. While, the morphology of FHAp from crocodile eggshell as CaCO3 form with different in phosphorus and fluoride source showed the unique structure evolution from rod-like hexagonal crystals, dumbbell to ball shape. Two distinctive morphology, first when using NaF as fluoride source with (NH4)2HPO4 precursor show the large cubic structure in high magnification it is tufted hexagonal crystal and it bundle like structure. As the pH value decreases in NH4F, it increases crystal size. For H3PO4 as phosphate precursor found that unique structure evolution from rod-like hexagonal crystals to dumbbell structure and then form the sphere assembly with a size of several micrometers.

Origin of the alternate bright/dark contrast in HREM images of hexagonal crystals, particularly 6H-SiC

1993 ◽  
Vol 51 ◽  
pp. 914-915
Author(s):  
J.S. Bow ◽  
R.W. Carpenter ◽  
M.J. Kim
Keyword(s):  
High Resolution ◽  
Incident Beam ◽  
Hexagonal Crystal ◽  
Detailed Explanation ◽  
Similar Character ◽  
High Resolution Images ◽  
The Difference ◽  
Zigzag Shape ◽  
Hexagonal Crystals ◽  
Dark Contrast

A prominent characteristic of high-resolution images of 6H-SiC viewed from [110] is a zigzag shape with a period of 6 layers as shown in Fig.1. Sometimes the contrast is same through the 6 layers of (0006) planes (Fig.1a), but in most cases it appears as in Fig.1b -- alternate bright/dark contrast among every three (0006) planes. Alternate bright/dark contrast is most common for the thicker specimens. The SAD patterns of these two types of image are almost same, and there is no indication that the difference results from compositional ordering. O’Keefe et al. concluded this type of alternate contrast was due to crystal tilt in thick parts of the specimen. However, no detailed explanation was given. Images of similar character from Ti3Al, which is also a hexagonal crystal, were reported by Howe et al. Howe attributed the bright/dark contrast among alternate (0002) Ti3Al planes to phase shifts produced by incident beam tilt.

Controlled Hydrothermal Growth of CuO-Based Nanostructures from Copper Alginate

2011 ◽  
Vol 688 ◽  
pp. 19-22 ◽  
Author(s):  
Bing Bing Wang ◽  
Qing Shan Kong ◽  
Jian Ping Sun ◽  
Quan Feng Yu ◽  
Quan Ji ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Growth Mechanism ◽  
Hydrothermal System ◽  
Ph Value ◽  
Structure Evolution ◽  
Structure Directing Agent ◽  
Aggregation State ◽  
Air Atmosphere ◽  
Morphology And Structure ◽  
Different Temperatures

Schistose and aciculate CuO nanostructures have been synthesized by a novel ammonia assisted hydrothermal method of copper alginate. The conversion processes of copper alginate are investigated by thermogravimetrics (TG) analyses under N2and air atmosphere. The morphology, structure, and composition of the obtained CuO are investigated using SEM,TEM and XRD. It is found that different temperature and pH value resulted in the morphology and structure evolution of CuO. Ammonia was used as structure-directing agent in the hydrothermal system. The aggregation state of the nanostructures was controlled by the temperature. Dispersive schistose structures about 1μm in diameter were synthesized with 0.5mL ammonia at different temperatures. Dispersive microspheres of about 4 μm in diameter were also synthesized with 1 mL ammonia. Microspheres composed of nanoneedles and nanoplates were synthesized at 120°C and 160°C, respectively. Moreover, a possible growth mechanism governing the formation of such a nanomicrostructure was primarily discussed.

scholarly journals Synthesis of nanosized magnetic NiFe2O4 material by a coprecipitation method

2016 ◽  
Vol 19 (4) ◽  
pp. 137-143
Author(s):  
Tien Anh Nguyen ◽  
Dat Tien Nguyen
Keyword(s):  
Calcination Temperature ◽  
Crystal Size ◽  
Coprecipitation Method ◽  
Boiling Water ◽  
Cubic Structure ◽  
Hydrolysis Of

Nanosized NiFe2O4 spinel material has been synthesized by the coprecipitation method by hydrolysis of Ni(II) and Fe (III) cations in boiling water. The DTA/TGA, XRD, SEM, TEM, VSM results showed that NiFe2O4 crystals formed after calcinating at 700 oC for 2 h exhibited the cubic structure, with the size of 30-50 nM. Mr, Ms and Hc values were 1.06 emu/g, 14.94 emu/g and 61.57 Oe, respectively. The crystal size significantly increased with increasing calcination temperature.

scholarly journals Фактор предпочтения базисной краевой дислокационной петли в цирконии. Численный анализ

2020 ◽  
Vol 62 (12) ◽  
pp. 2087
Author(s):  
А.В. Бабич ◽  
В.Ф. Клепиков ◽  
П.Н. Остапчук
Keyword(s):  
Elastic Anisotropy ◽  
Elastic Field ◽  
Elastic Interaction ◽  
Growth Theory ◽  
Hexagonal Crystal ◽  
Bias Factor ◽  
Area Of Influence ◽  
Hexagonal Crystals ◽  
Toroidal Geometry

Recent numerical calculations of the diffusion coefficients of radiation point defects in hexagonal crystals have made it clear that the main assumption of the radiation growth theory of zirconium (DAD - diffusional anisotropy difference) does not allow one to describe the radiation growth correctly. Thus, the elastic ideology (EID - elastic interaction difference), based on the concept of the flow bias factor, remains relevant. Therefore, the bias factor for the basic edge loop of zirconium in a toroidal reservoir was calculated numerically (using the finite difference method), taking into account the elastic anisotropy of the hexagonal crystal. The toroidal geometry of the reservoir makes it possible to calculate the flows for a loop of any size and without any correction of the elastic field in its area of influence. The dependences of the loop bias factor on its radius and nature are obtained for various sink densities. The essential role of the form of the boundary condition on the outer surface of the reservoir is shown. The prospects for further research in the construction of the theory of the radiation growth of zirconium based on the elastic ideology are discussed.

Laser Induced Chemical Deposition of Ferrihydrite Nanotubes: Exploring Growth Rate and Crystal Structure

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Zhikun Liu ◽  
C. Richard Liu
Keyword(s):  
Crystal Structure ◽  
Growth Rate ◽  
Laser Scanning ◽  
Crystal Size ◽  
Ph Value ◽  
Chemical Deposition ◽  
High Rate ◽  
Solution Synthesis ◽  
Initial Finding ◽  
High Consistency

This paper is one of three papers exploring and confirming a novel high rate nanomanufacturing method using laser to induce and accelerate chemical synthesis and deposition of nanotubes. We have shown elsewhere that the growth rate of SnO2 nanotubes by this method is a few orders faster than that by the state of the art electrochemical deposition method, the growth rate of the nanotubes is favorably affected by increasing the laser power under a constant number of scanning passes, and the process can grow nanotubes coalesced from ultrasmall particle size as small as 2 nm (Liu and Liu, 2013, "Laser Induced Chemical Solution Deposition of Nanomaterials: A Novel Process Demonstrated by Manufacturing SnO2 Nanotubes," Manuf. Lett., 1(1), pp. 42–35). In the second paper, we have shown that this novel method is generic, demonstrated by synthesizing various metal oxide and sulfide nanotubes (Liu and Liu, "Laser-Induced Solution Synthesis and Deposition: A Generic Method to Make Metal Chalcogenide Nanotubes at High Rate With High Consistency," J. Nanoeng. Nanosyst. (accepted)). Since the performance and properties of nanomaterials are highly dependent on its structure, we explore here how the basic processing variables affect the growth rate and crystal size. Our initial finding is that (1) the growth rate can be increased by increasing the pH value of the solution, resulting in little change on the crystal size and (2) the crystal size of the manufactured ferrihydrite nanotube arrays can be controlled by changing laser scanning passes. We found the increase of the pH value from 1.33 to 2.16 almost tripled the growth rate of ferrihydrite nanotubes, while the crystal size remained little changed as revealed by the transmission electron microscopy studies. However, increasing the number of laser scanning passes at a given power could coarsen the ferrihydrite nanocrystals. The crystal structure of the nanotubes could be converted to haematite by dry furnace annealing. These initial findings demonstrated the capability and controllability of the novel process.

Hydrothermal Preparation of Hydroxyapatite/Chitosan Nanocomposites via In Situ Precipitation

2007 ◽  
Vol 330-332 ◽  
pp. 405-408
Author(s):  
Xiao Ying Lu ◽  
Zh. Liu ◽  
Jie Weng
Keyword(s):  
Crystal Size ◽  
Ph Value ◽  
Hydrothermal Process ◽  
Hydrothermal Preparation ◽  
Nano Structure ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
Low Crystalline ◽  
Electronic Microscope

The cylindrical chitosan (CS)/hydroxyapatite (HA) nanocomposites were hydrothermally prepared via in situ precipitation and characterized by x-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), thermogravimetry (TG) and scanning electronic microscope (SEM). The results show that the as-prepared products are composed of CS and low-crystalline HA phases, and some extent of interaction between CS and HA phases exists in the composites, which is greatly influenced by the temperature and pH value in the hydrothermal process. The crystal size of HA uniform-distributed in CS matrix is calculated to be no larger than 100nm while the crystallinity of CA is greatly increased in the hydrothermal process, which is beneficial to the mechanical properties of the composites. It is proposed that the nano-structure of HA/CS composite will have the better biomedical properties in the biomaterials applications.

scholarly journals PEMBUATAN PASTA DAN PEMBENTUKAN LAPISAN TIPIS HIDROKSI APATIT KARBONAT

2015 ◽  
Vol 7 (2) ◽  
pp. 161
Author(s):  
Selfa Dewati Samah ◽  
Syukri Arief ◽  
Novesar Jamarun
Keyword(s):  
Thick Film ◽  
Screen Printing ◽  
Crystal Size ◽  
Xrd Analysis ◽  
Hexagonal Crystal ◽  
Screen Printing Method ◽  
Carbonated Hydroxyapatite ◽  
Particle Size Analyzer ◽  
Bet Analysis ◽  
Phosphate Carbonate

 ABSTRACTPaste of Carbonated Hydroxyapatite (CHA) as a biocompatible material that can be used in thebone and teeth repair has been developed on preparation of thick film. CHA paste was preparedby mixing precipitate of CHA with CaSO4 and polyethylene glycol (PEG) in 2-propanol assolvent. Paste was deposited on substrate to get thick films by screen printing method. X raydiffraction (XRD) analysis has shown hexagonal crystal structure and crystal size of CHAacquired 7,2 nm by Scherrer’s method. Fourier Transform Infrared (FTIR) analysis has shownabsorption spectra which indicating phosphate, carbonate, and hydroxide group. Size of thiscomposite particles analyzed by PSA (particle size analyzer) about 3μm and pore size was 0.44-0.49 nm obtained from BET analysis, increased with the addition of CaSO4 (0.44 to 0,49 nm).Rephrase PEG was found as an adhesive and homogenize paste on substrat surface. In addition,CHA paste also potentially can be used as bone cement.Keywords : Paste, thick film, carbonated hydroxyapatite

scholarly journals Micro-CT Characterization of Wellbore Cement Degradation in SO42-–Bearing Brine under Geological CO2 Storage Environment

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Manguang Gan ◽  
Liwei Zhang ◽  
Xiuxiu Miao ◽  
Yan Wang ◽  
Xiaojuan Fu ◽  
...  
Keyword(s):  
Ph Value ◽  
Ambient Pressure ◽  
Co2 Storage ◽  
Low Ph ◽  
Structure Evolution ◽  
Micro Ct ◽  
Ct Scanner ◽  
Cement Sample ◽  
Curing Conditions ◽  
Significant Difference

In order to explore the process of acid- and CO2-induced degradation of wellbore cement and the development of pre-existing leakage channels in wellbore cement under sulfate-rich geological CO2 storage conditions, wellbore cement samples were immersed in SO42--bearing brine solution for 7 days, and the samples after reacting with the low and circumneutral pH solutions were scanned by a micro-CT scanner. HCl+Na2SO4 solution was used to simulate the low-pH condition in deep formation waters and the possible existence of high sulfate ion content in deep formation waters. The acidification and carbonation results were compared, and the results given different pH values and different curing conditions were compared as well. The results show that the degradation of cement was related to the pH value of the reaction solution. There was a significant dissolution in the exterior of the cement sample after exposure to the low-pH solution, but the dissolution surrounding a penetrating borehole at the center of the sample (mimicking a leakage pathway within the wellbore cement in geological CO2 storage environment) was limited. Comparison between acidification and carbonation results in this study shows formation of a thick carbonate layer due to cement carbonation, and this layer was not observed in the acidification result. As for different curing conditions of cement samples, no significant difference in cement alteration depth was observed for the acidification case. For the carbonation case, precipitations in the borehole occurred in the cement sample cured at ambient pressure, while the cement sample cured at high pressure did not produce any precipitation in the borehole. This study provides valuable information on how low pH-induced corrosion and HCO3--induced cement carbonation contribute to structure evolution of wellbore cement in SO42--bearing brine under geological CO2 storage environment.

Photocatalytic Activity of Bi2O3 Prepared by Different pH Value

2011 ◽  
Vol 418-420 ◽  
pp. 554-557 ◽  
Author(s):  
Yan Lu ◽  
Xi Yang He ◽  
Jun Bo Zhong ◽  
Jian Zhang Li ◽  
Wei Hu
Keyword(s):  
Photocatalytic Activity ◽  
Surface Area ◽  
Diffuse Reflectance ◽  
Crystal Size ◽  
Photocatalytic Performance ◽  
Ph Value ◽  
Strong Dependence ◽  
Bet Surface Area ◽  
Precipitation Method ◽  
Average Crystal Size

Abstract. Bismuth oxide is an important metal-oxide semicondutor, the interest in developing methods which can prepare Bi2O3 with unique properties has been a hot issue recently. In this paper, paralled flaw precipitation method has been employed to synthesize nanostructured Bi2O3. It is found that the bandgap and photocatalytic performance of Bi2O3 has a strong dependence on the pH value of precipitation reaction.The prepared photocatalysts were characterized by BET, XRD and UV-Vis diffuse reflectance. The results show that Bi2O3 prepared under pH value 8.5 has the highest BET surface area, pore volume, the smallest pore size and the average crystal size. Bi2O3 prepared under pH value 8.5 exhibits the best photocatalytic activity. The results of further experiments show that bandgap and the specific surface area all play an important role in promotion of photocatalytic activity of Bi2O3 prepared under pH 8.5.

Contrast factors of dislocations in the hexagonal crystal system

2002 ◽  
Vol 35 (5) ◽  
pp. 556-564 ◽  
Author(s):  
I. C. Dragomir ◽  
T. Ungár
Keyword(s):  
Lattice Distortion ◽  
Dislocation Model ◽  
Size Distributions ◽  
Hexagonal Crystal ◽  
Strain Anisotropy ◽  
Dislocation Densities ◽  
Contrast Factor ◽  
Parameter Values ◽  
Hexagonal Crystals ◽  
Hexagonal Materials

Strain anisotropy can be well accounted for by the dislocation model of lattice distortion. In a texture-free powder or polycrystal, or if all possible Burgers vectors are equally populated, the dislocation contrast factors are a linear function of the fourth-order invariants of thehklindices. Using this relation the dislocation contrast factors have been evaluated numerically and compiled for a number of common hexagonal materials. A procedure is presented to match experimentally determined contrast factor parameters with the numerically obtained parameter values. The procedure can be used as a tool to extract the microstructure from strain anisotropy in terms of Burgers vector populations, dislocation densities, crystallite size and size distributions in hexagonal crystals. Its practical use is illustrated by the application to plastically deformed titanium.

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