scholarly journals Effect of titanium addition on thermal stability of hydroxyapatite/zirconia nanocomposite

2015 ◽  
Vol 47 (1) ◽  
pp. 107-112 ◽  
Author(s):  
L.I. Wang ◽  
X.F. Wang ◽  
C.L. Yu ◽  
Y.Q. Zhao
Keyword(s):  
Thermal Stability ◽  
Sintering Temperature ◽  
Thermal Reaction ◽  
Wet Chemical Method ◽  
Sem Images ◽  
Titanium Addition ◽  
Wet Chemical ◽  
The Individual ◽  
Individual Particles ◽  
Thermal Stability Of

HA/ZrO2 composite nanpowder with various addition of titanium (0.2-2.4wt%) were synthesized via wet chemical method using ZrOCl2.8H2O, H3PO4, Ca(OH)2 and tetraethylorthotitanate as precursor materials. The composites were then sintered at 900-1200?C for 2h, respectively. Effect of titanium addition to the composite on the phase composition and thermal stability during thermal treatment was investigated. The results suggested that as the sintering temperature increased from 900?C to 1200?C and with the addition of titanium to the composite below 0.8wt%, main phases were HA and ZrO2. As the sintering temperature increased to 1200?C and with the addition of titanium to the composite above 0.8wt%, main phases were HA, ZrO2 and a small amount of dicalcium phosphate (DCP). There were still no tricalcium phosphate (?-TCP) and CaZrO3 phases observed, which indicated that the addition of titanium restrained decomposition of HA and thermal reaction between HA and ZrO2. It also suggested that the addition of 0.8wt% titanium to the composite was optimum for producing HA/ZrO2 composite nanopowder with expected main phases. With the addition of 0.8wt% titanium to the composite, SEM images showed that the individual particles of the two materials were still visible, which also implied that the reaction between HA and ZrO2 did not occur.

scholarly journals Sintering behavior and property of bioglass modified HA-Al2O3 composite

2012 ◽  
Vol 44 (3) ◽  
pp. 265-270
Author(s):  
Li-li Wang ◽  
Xiu-Feng Wang ◽  
Xu Ding ◽  
Jian-feng Zhu
Keyword(s):  
Production Cost ◽  
Chemical Method ◽  
Sintering Temperature ◽  
Volume Density ◽  
Sintering Behavior ◽  
Wet Chemical Method ◽  
Al2o3 Composite ◽  
Wet Chemical ◽  
Different Content ◽  
Sintered Temperature

The bioglass modified HA-Al2O3 composites were successfully fabricated by mixing HA, synthesized by wet chemical method between precursor materials H3PO4 and Ca(OH)2, with 25wt% Al2O3 and different content of bioglass (5%, 25%, 45%, 65wt%) respectively, with a mole fraction of 53.9%SiO2, 22.6%Na2O, 21.8%CaO, and 1.7wt%P2O5, sintered in air at various temperatures (750-950?C) for 2h. when the content of bioglass is below 45wt% in the composite, HA decomposes completely and transforms to ?-TCP. The main phase in this case are ?-TCP, Al2O3 and Ca3(AlO3)2.When the content of bioglass is above 45wt% in the composite, the decomposition of HA to ?-TCP is suppressed and the main phases in this case are Al2O3 and HA, DCP?CaHPO4? and ?-TCP, which almost have the same chemical composition, forming ternary-glass phase, and have better bioactive than pure HA. It can also be found that at the certain addition of bioglass, the higher sintered temperature, the bigger volume density and flexural strength of the composite are, but when the sintered temperature reaches 950?C, they decrease. This modified HA-Al2O3 composites by calcium silicate glass have a much lower sintering temperature and decrease the production cost much.

Effects of Powder Synthesis Method on the Sinterability of Hydroxyapatite

2011 ◽  
Vol 264-265 ◽  
pp. 1538-1544 ◽  
Author(s):  
K.L. Aw ◽  
R. Tolouei ◽  
Ramesh Singh ◽  
Chou Yong Tan ◽  
Wei Hong Yeo ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Sintering Temperature ◽  
Synthesis Method ◽  
Theoretical Density ◽  
Wet Chemical Method ◽  
Powder Synthesis ◽  
Temperature Range ◽  
Increasing Trend ◽  
Wet Chemical ◽  
Better Than

The sinterability of hydroxyapatite (HA) powder synthesized through a novel wet chemical method (HAp) and a wet mechanochemical method (HAwm) was investigated over a temperature range of 1000oC to 1400oC in terms of phase stability, bulk density, hardness and fracture toughness. The results indicated that the sinterability of HAp powder were significantly better than HAwm powder. Moreover, the XRD traces of HAwm sintered samples showed signs of decomposition into TTCP when sintered at 1300oC and above. Densification of ~98% of theoretical density was attained by HAp compacts at 1100oC while the HAwm compacts exhibited only ~96% of theoretical density even at 1350oC with no significant increase of density at 1400oC. The Vickers hardness of HAp showed increasing trend for temperature range of 1000oC to 1100oC with the compacts attaining HV of ~7 GPa at 1100oC. Subsequently, the hardness decreased with increasing sintering temperature though the value does not dropped below ~5 GPa. Similarly, HAwm compacts showed an increasing trend from 1000oC to 1300oC with the largest HV attained was ~4.57 GPa. Further increased in sintering temperature resulted in the decreased of Vicker’s hardness. Moreover, the HAp samples reached a maximum fracture toughness of ~0.9 MPam1/2 at 1050oC while the HAwm attained maximum KIc of only ~0.7 MPam1/2 at 1300oC.

Thermal stability of metalorganic compounds on volcanic olivine

2020 ◽  
Author(s):  
Joanna Brau ◽  
Marco Matzka ◽  
Philippe Schmitt-Kopplin ◽  
Norbert Hertkorn ◽  
Werner Ertel-Ingrisch ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Treatment ◽  
Tube Furnace ◽  
Stability Field ◽  
Secondary Phases ◽  
The Stability ◽  
The Individual ◽  
Gas Tight ◽  
Metalorganic Compounds ◽  
Thermal Stability Of

<p>Previously unknown class of metalorganic compounds revealed in meteorites [1] also found on the surfaces of silicate phases such as olivine, may have been involved in the emergence of life.  Here, the thermal stability of such organic compounds has been experimentally investigated under conditions which simulate those extant on the early Earth. We have studied olivines from the Hawaiian eruptions of 1959 and 2018. Individual mineral grains have been hand-picked to be free of secondary phases such as pyroxene or melt. We use a high temperature gas-tight tube furnace under CO-CO<sub>2</sub> gas mixture at temperatures ranging from 950°C to 1350°C and oxygen fugacity ranging from 10<sup>-12</sup> to 10<sup>-10 </sup>bar, within the stability field of olivine. The samples were contained in Pt crucibles and held for dwell times of 1 to 64 h. Quenching was performed by lifting the samples vertically out of the tube furnace. Using EPMA (electron microprobe analyzer) and RAMAN spectroscopy, we have mapped the state of the olivine samples. We observe that the composition of the individual mineral grains remains stable and homogeneous with thermal treatment. We are also investigating the role of impurities and cracks in the natural olivine and synthetic forsterite that might influence our study. The metalorganic cargo of these olivines has been analyzed using FT-ICR-MS (Fourier Transform ion cyclotron mass spectrometry). Preliminary results reveal systematic changes or organic molecular composition depending on time and heat of thermal treatment whose origins will be discussed.</p><p>[1] A. Ruf, B. Kanawati, N. Hertkorn, Q. Yin, F. Moritz, M. Harir, M. Lucio, B. Michalke, J. Wimpenny, S. Shilobreeva, B. Bronsky, V. Saraykin, Z. Gabelica, R. D. Gougeon, E. Quirico, S. Ralew, T. Jakubowski,  H. Haack, M. Gonsior, P. Jenniskens, N. W. Hinman, P. Schmitt-Kopplin. (2017) Previously unknown class of metalorganic compoundsrevealed in meteorites. PNAS 114 (2017) 2819-2824.</p>

Electrophoretic Deposition of Hydroxyapatite Nano Coating on Etched Titanium Surface

2005 ◽  
Vol 288-289 ◽  
pp. 183-186 ◽  
Author(s):  
F. Chen ◽  
L.W. Lin ◽  
Chang Jian Lin ◽  
W.W. Lu
Keyword(s):  
Mechanical Properties ◽  
Electrophoretic Deposition ◽  
Chemical Method ◽  
Titanium Surface ◽  
Sintering Temperature ◽  
Deposition Process ◽  
Wet Chemical Method ◽  
Nano Structure ◽  
Nano Coating ◽  
Wet Chemical

Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) is biocompatible and bioactive, however, it is relatively brittle. The development of HAp coatings on medical metal surface is a good way to improve the mechanical properties of HAp. In the present study, a HAp coating with nano-structure on a roughened titanium surface was developed by electrophoretic deposition process. To decrease sintering temperature HAp nanoparticles synthesized by a wet chemical method was used. It was observed that the coating was uniform and showed no cracks. After sintering the HAp coating still remained nano structured. The surface treatment of Ti was applied to form a distribution of small pits and a TiO2 thin layer on the Ti surface that improves the adhesion of coating to the Ti substrate. It was shown that the bonding strength of coating was 18 ± 2.5MPa. The hardness and Young’s modulus were 40.6 and 0.42 GPa, respectively.

Thermal and mechanical properties of polymethyl mathacrylate reinforced by polyhedral oligomeric silsesquioxane

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Benghong Yang ◽  
Meng Li ◽  
Bangping Song ◽  
Yun Wu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Thermal And Mechanical Properties ◽  
Sem Images ◽  
Pmma Matrix ◽  
Oligomeric Silsesquioxane ◽  
Tga And Dsc ◽  
Thermal Stability Of

AbstractA series of Inorganic/organic nanocomposites were prepared by blending cage-like carboxyl-bearing polyhedral oligomeric silsesquioxane (carboxyl-POSS) with polymethyl mathacrylate (PMMA) in THF solvent. FTIR and 29Si-NMR were employed to characterize the structures of the nanocomposites. SEM images showed that the as-prepared films were smooth and no aggregation of carboxyl-POSS was observed. TGA and DSC results showed that the incorporation of small amount of nanosize carboxyl-POSS enhanced the thermal stability of PMMA. When 1.0 wt% of carboxyl-POSS was incorporated into PMMA matrix, the Tg and Td increased by 16.9 °C and 21.0 °C, respectively. However, higher POSS contents (>1.0 wt%) would deteriorate the thermal and mechanical properties of the nanocomposites.

Synthesis, Sintering and Microstructural Characterization of Nanocrystalline Hydroxyapatite Composites

2004 ◽  
Vol 845 ◽  
Author(s):  
B. Viswanath ◽  
N. Ravishankar ◽  
Suprabha Nayar ◽  
Arvind Sinha
Keyword(s):  
Mechanical Properties ◽  
Chemical Method ◽  
Sintering Temperature ◽  
Microstructural Characterization ◽  
Wet Chemical Method ◽  
Maximum Value ◽  
Nanocrystalline Hydroxyapatite ◽  
Wet Chemical ◽  
Nanocrystalline Alumina

ABSTRACTNanocrystalline hydroxyapatite (HAp) exhibits better bioactivity and biocompatibility with enhanced mechanical properties compared to the microcrystalline counterpart. In the present work, nanocrystalline hydroxyapatite was synthesized by wet chemical method. Sintering was carried out with nanocrystalline alumina as additive, the content of alumina being varied from 10 to 30 wt% in the composite. For 20 and 30 wt % Al2O3, hydroxyapatite decomposed into tricalcium phosphate (TCP) above the sintering temperature of 1100°C. The fracture toughness of nano HAp-nano Al2O3 composite is anisotropic in nature and reached a maximum value of 6.9 MPa m1/2.

Study on Flammability Characteristics and Thermal Stability of Flame-Retardant PA Fibers

2013 ◽  
Vol 631-632 ◽  
pp. 277-280 ◽  
Author(s):  
Jian Min Zhao ◽  
Li Wen Tan
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Flame Retardant ◽  
Sem Images ◽  
Tg Analysis ◽  
Flammability Characteristics ◽  
Degradation Activation Energy ◽  
Thermal Stability Of ◽  
Better Than

The flammability characteristics and thermal stability were studied based on LOI, TG analysis and SEM tests. The results revealed that the additive flame retardant enhanced the flame retardancy of PA. The TG analysis showed that the thermal stability of flame-retardant PA fibers was better than PA fibers, because flame-retardant PA fibers got higher residue content and thermal degradation activation energy. The SEM images indicated the flame retardant residues were infusible, which can impede the molten dropping of PA fibers during combustion.

scholarly journals The preparation of nylon-tube-supported hexokinase and glucose 6-phosphate dehydrogenase and the use of the co-immobilized enzymes in the automated determination of glucose.

1975 ◽  
Vol 147 (3) ◽  
pp. 593-603 ◽  
Author(s):  
D L Morris ◽  
J Campbell ◽  
W E Hornby
Keyword(s):  
Thermal Stability ◽  
Automated Analysis ◽  
Immobilized Enzymes ◽  
Nylon Tube ◽  
The Individual ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Thermal Stability Of ◽  
Automated Determination

Triethyloxonium tetrafluoroborate was used to O-alkylate nylon-tube thus producing the imidate salt of the nylon which was further made to react with 1,6-diaminohexane. 2. Hexokinase (EC 2.7.1.1) and glucose 6-phosphate dehydrogenase (EC 1.1.1.49) were immobilized on the amino-substituted nylon tube through glutaraldeyde and bisimidates. 3. The effect of varying the conditions of O-alkylation and the amount of enzyme immobilized on the activity of nylon tube-hexokinase derivatives was determined. 4. The effect of varying the amount of enzyme immobilized on the activity of nylon-tube-glucose 6-phosphate dehydrogenase derivatives was determined. 5. The thermal stability of nylon-tube-hexokinase and nylon-tube-glucose 6-phosphate dehydrogenase derivatives was studied. 6. Different ratios of hexokinase and glucose 6-phosphate dehydrogenase were co-immobilized on nylon tube, and the rate of conversion of glucose into 6-phosphogluconolactone was compared with the individual activities of the immobilized enzymes. 7. Hexokinase and glucose 6-phosphate dehydrogenase co-immobilized on nylon tube were used in the automated analysis of glucose.

The Surface Coating of YAG:Ce Phosphors with ZnO Nanoparticles for White LED

2011 ◽  
Vol 675-677 ◽  
pp. 1283-1286 ◽  
Author(s):  
Ke Fu Chao ◽  
Zhi Guo Xiao ◽  
Hong Wei Zhang ◽  
Wen Bin Niu ◽  
Wei Xia ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Ethanol Solution ◽  
Photoluminescence Intensity ◽  
White Led ◽  
Wet Chemical Method ◽  
Sem Images ◽  
Xps Spectra ◽  
Surface Character ◽  
Wet Chemical ◽  
The Cost

In this work, YAG: Ce phosphors coated with ZnO nanoparticles were prepared based on the wet chemical method in ethanol solution at low temperature. The surface character was characterized by XPS and SEM. The XPS spectra showed that the peak positions corresponding to the Zn 2p3/2 , Zn 2p1/2 and O 1s are 1022.08 eV, 1044.88 eV and 530. 8 eV, respectively. The SEM images showed that the surface of YAG:Ce were coated with ZnO nanoparticles. The thickness is about 25 nm. The luminescence properties of YAG:Ce phosphors coated with ZnO nanoparticles were studied. It is found that the photoluminescence intensity of coated phoshors increases a maximum at 12% compared with that of the uncoaed YAG: Ce phosphors and the enhancement of photoluminescence intensity depends on the consistency of ZnO nanoparticles. Finally, the YAG: Ce phosphors coated with ZnO nanoparticles were used for LED package. The results show that the luminescent intensity increases 6.8 % and the quantity of phosphors decreases 1 %. It is important for the lighting product to improve the luminescence intensity of white LED and decrease the cost of package.

Sign in / Sign up

Export Citation Format

Share Document