Apatite-Leucite Micro/Nano Crystals from Aluminosilicate Glasses for Dental Applications

2011 ◽  
Vol 694 ◽  
pp. 435-439
Author(s):  
Pat Sooksaen ◽  
Faisol Panyusoh ◽  
Siwat Atthapinan ◽  
Wonrawee Wae Noh
Keyword(s):  
Crystal Structure ◽  
Fracture Toughness ◽  
Chemical Bonding ◽  
Vickers Microhardness ◽  
Glass Ceramics ◽  
Aluminosilicate Glasses ◽  
Powder Samples ◽  
Different Temperatures ◽  
Ft Ir ◽  
Dental Applications

Needle-like apatite-leucite glass-ceramics were synthesized in the SiO2-Al2O3-Na2O-K2O-P2O5 CaO-CaF2 system. Four glass batches were prepared by varying SiO2/P2O5 ratio, then melted and quenched. Crystallization was studied in compacted powder samples at different temperatures. Glasses were characterized for chemical bonding by FT-IR, phases and crystal structure by XRD, microstructure by SEM and hardness and fracture toughness by Vickers microhardness.

Improvement of the Mechanical Properties of Glasses Based on the 3CaO.P2O5-SiO2-MgO System after Heat-Treatment

2010 ◽  
Vol 636-637 ◽  
pp. 41-46 ◽  
Author(s):  
J.K.M.F. Daguano ◽  
Claudinei dos Santos ◽  
Paulo Atsushi Suzuki ◽  
Luiz A. Bicalho ◽  
Maria Helena F.V. Fernandes
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Glass Ceramics ◽  
Xrd Analysis ◽  
Phase Content ◽  
Heat Treated ◽  
Different Temperatures ◽  
Hardness Values ◽  
Crystallization Degree ◽  
Temperature Crystallization

Glasses based on the 3CaO.P2O5-SiO2-MgO system present high bioactivity aiming the use as bone restorations. On the other hand, the low mechanical properties reduce the importance of this glass aiming the use as restoration bulk specimens. In this work, glass-ceramics were obtained by devitrification of this glass using different temperatures. CaCO3, SiO2, MgO and Ca(H2PO4).H2O were used as starting-powders. Powder mixture was milled/homogenized and melted at 1600°C, for 2h and annealed at 700°C for 4h with cooling rate of 3°C/min. Glass specimens of 151550mm3 were characterized by DTA and XRD analysis. Specimens were heat-treated in different temperatures between 7000C and 1050°C, for 4 hours, obtaining glass-ceramics with different crystallized phase content. Hardness and fracture toughness were determined and correlated with crystalline phase content. The results indicated that crystallization-degree increase with the temperature, and the mechanical properties are improved: Hardness values present increases lower than 20% as function of the crystallization. Fracture toughness may increase 100% as function of temperature (crystallization degree).

Microstructural and Mechanical Properties of Er2O3-ZrO2 Ceramics with Different Er2O3 Contents

2012 ◽  
Vol 31 (6) ◽  
pp. 701-706 ◽  
Author(s):  
Süleyman Tekeli ◽  
Bülent Aktaş ◽  
Mustafa Küçüktüvek
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Vickers Hardness ◽  
Lattice Parameter ◽  
Erbium Oxide ◽  
Cubic Crystal ◽  
Hardness Tester ◽  
Different Temperatures

AbstractIn this study, the effect of erbium oxide (Er2O3) addition on the microstructure, sinterability and mechanical properties of cubic zirconia (c-ZrO2) was investigated. 0–15 wt% Er2O3 and c-ZrO2 powders were mixed by means of colloidal processing and the specimens were sintered at different temperatures for 1 hour. The XRD results showed the existence of cubic crystal structure in all specimens. The lattice parameter of the specimens decreased with increasing Er2O3 addition up to 10 wt% and remained unchanged after this amount. The grain size of the Er2O3 doped c-ZrO2 specimens dropped up to 5 wt% Er2O3 addition and stayed almost unchanged at higher Er2O3 contents. Both hardness and fracture toughness measurements were done using Vickers hardness tester. The fracture toughness values of the undoped, 1, 5, 10 and 15 wt% Er2O3 doped c-ZrO2specimens were found to be 1.64 MPam1/2, 1.77 MPam1/2, 2.06 MPam1/2, 2.57 MPam1/2 and 2.31 MPam1/2 respectively.

scholarly journals Synthesis, growth and characterization of organic crystal triphenylmethane p-nitroaniline: a nonlinear optical crystal

2017 ◽  
Vol 35 (3) ◽  
pp. 667-672 ◽  
Author(s):  
G. Bhuvaneswari ◽  
L. Guru Prasad ◽  
N. Prabhavathi
Keyword(s):  
Vickers Microhardness ◽  
Dielectric Studies ◽  
Slow Evaporation ◽  
Nonlinear Optical Crystal ◽  
Growth Technique ◽  
Xrd Pattern ◽  
Different Temperatures ◽  
Ft Ir ◽  
Solution Growth Technique

AbstractA triphenylmethane-4-nitroaniline salt has been synthesized and the crystals have been grown by using slow evaporation solution growth technique. The grown single crystal was investigated by recording the powder XRD, FT-IR spectrum, UV-Vis spectrum, Vickers microhardness test, dielectric measurements and powder SHG. The growth of crystal was confirmed by analyzing the XRD pattern and it was stated that the grown material crystallized in triclinic system. Vibrational peaks of the functional groups existing in the compound were identified. Vickers microhardness studies were carried to measure the mechanical strength. In order to identify the phase transition temperature, the dielectric studies were carried out at different temperatures. Dielectric constant, dielectric loss and impedance of the crystal were monitored with respect to the frequency of electric field.

Structural, Thermal and Electrical Properties of Doped Poly(3,4 ethylenedioxythiophene)

2016 ◽  
Vol 10 (4) ◽  
pp. 395-400 ◽  
Author(s):  
Deepali Kelkar ◽  
◽  
Ashish Chourasia ◽  
◽  
Keyword(s):  
Crystal Structure ◽  
Electrical Properties ◽  
Xrd Analysis ◽  
Structure Modification ◽  
Camphorsulfonic Acid ◽  
Thermal And Electrical Properties ◽  
Ft Ir

Poly(3,4-ethylenedioxythiophene) (PEDOT) was chemically synthesized, undoped and then re-doped using FeCl3 as well as camphorsulfonic acid (CSA). FT-IR results confirm the nature of the synthesized and doped samples. XRD analysis indicates crystal structure modification after doping and was also used to calculate crystallinity of samples. Crystallinity increases after FeCl3 doping, whereas it reduces due to CSA doping. TGA-DTA results show reduction in Tg value for FeCl3 doped sample while it increases for CSA doped samples compared to that of undoped PEDOT. Reduction in Tg indicates plasticizing effect of FeCl3 whereas increase in Tg show anti-plasticizing effect of CSA in PEDOT. Conductivity value () increases by two orders of magnitude after doping. Log vs. 1/T graph show metallic nature of undoped PEDOT above 308 K, however both doped samples show semiconducting nature from 301 to 383 K.

scholarly journals Effect of Powder Heat Treatment on Chemical Composition and Thermoelectric Properties of Bismuth Antimony Telluride Alloys Fabricated by Combining Water Atomization and Spark Plasma Sintering

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2993
Author(s):  
Dong-won Shin ◽  
Peyala Dharmaiah ◽  
Jun-Woo Song ◽  
Soon-Jik Hong
Keyword(s):  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
Hole Concentration ◽  
Bismuth Antimony Telluride ◽  
Plasma Sintering ◽  
Heat Treated ◽  
Water Atomization ◽  
Powder Samples ◽  
Different Temperatures ◽  
Spark Plasma

In this work, Bi0.5Sb1.5Te3 materials were produced by an economically viable and time efficient water atomization process. The powder samples were heat treated at different temperatures (673 K, 723 K, 743 K, 773 K, 803 K, and 823 K) followed by spark plasma sintering (SPS). It was found that the Te evaporated slightly at 723 K and 743 K and became dominated at 773 K, 803 K, and 823 K, which severely influences the thermoelectric properties. The electrical conductivity was significantly improved for over 803 K heat treated samples due to the remarkable improvement in hole concentration. The power factor values for the 803 K and 823 K samples were significantly larger at T > 350 K compared to other samples. Consequently, the peak ZT of 0.92 at 350 K was obtained for the 803 K sample, which could be useful in commercial thermoelectric power generation.

Anderson-Stuart Model to Analyze AC and DC Conductivity of Lithium Zinc-Silicate Glass / Glass-Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 919-924
Author(s):  
M.S. Jogad ◽  
V.K. Shrikhande ◽  
A.H. Dyama ◽  
L.A. Udachan ◽  
Govind P. Kothiyal
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Low Frequency ◽  
Frequency Region ◽  
Dc Conductivity ◽  
Frequency Range ◽  
High Frequency Region ◽  
Dc Conductivities ◽  
Conductivity Variation ◽  
Different Temperatures

AC and DC conductivities have been measured by using the real (e¢) and imaginary (e¢¢) parts of the dielectric constant data of glass and glass-ceramics (GC) at different temperatures in the rage 297-642K and in the frequency range 100 Hz to 10 MHz. Using Anderson –Stuart model, we have calculated the activation energy, which is observed to be lower than that of the DC conductivity. The analysis for glass/glass-ceramics indicates that the conductivity variation with frequency exhibits an initial linear region followed by nonlinear region with a maximum in the high-frequency region. The observed frequency dependence of ionic conductivity has been analyzed within the extended Anderson–Stuart model considering both the electrostatic and elastic strain terms. In glass/glassceramic the calculations based on the Anderson-Stuart model agree with the experimental observations in the low frequency region but at higher frequencies there is departure from measured data.

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