Loading...
Search for:
crystallisation
0.011 seconds
Crystallisation kinetics of hydroxyapatite thin films prepared by sol-gel process
, Article Advances in Applied Ceramics ; Volume 109, Issue 6 , Jul , 2010 , Pages 313-317 ; 17436753 (ISSN) ; Nemati, A ; Sadeghian, Z ; Sharif University of Technology
Abstract
In this study, the crystallisation of nano hydroxyapatite (HA) films on stainless steel 316L was studied. The film was prepared by sol-gel technique. The process was started with preparation of an HA sol. After aging of the sol at room temperature, a stainless steel 316L substrate was dip coated and then was heat treated from 350 to 450°C at different periods of time in air. The crystallisation behaviour and the transformation-temperature-time diagram of HA films were achieved and analysed using the avrami equation. The results showed that the crystallisation of HA began at 250°C and was increased up to 450°C. The obtained HA film showed a nanostructure character with a suitable crystalinity...
Effects of nucleation agent particle size on properties, crystallisation and microstructure of glass-ceramics in TiO2-ZrO2-Li 2O-CaO- Al2O3-SiO2 system
, Article Advances in Applied Ceramics ; Volume 109, Issue 6 , 2010 , Pages 318-323 ; 17436753 (ISSN) ; Goharian, P ; Shabanian, M ; Afshar, A ; Sharif University of Technology
2010
Abstract
The objective of this study was to evaluate the effects of P 2O5 particle size distribution on the crystalline phases and microstructure of lithium disilicate glass-ceramics derived from the TiO2-ZrO2-Li2O-CaO-Al2O 3-SiO2 system for dentistry applications. The samples were made via fusion and casting procedure. Crystallisation as well as the morphology and microstructure of the samples were investigated using X-ray diffraction, differential scanning calorimetric and scanning electron microscopy. The results showed that the crystallisation of the samples occurred in the range of 500-650°C. The main crystalline phase was lithium disilicate (Li2Si2O5) along with Lithium metasilicate (Li2SiO3),...
Low temperature nanostructured lithium titanates: Controlling the phase composition, crystal structure and surface area
, Article Journal of Sol-Gel Science and Technology ; Volume 55, Issue 1 , 2010 , Pages 19-35 ; 09280707 (ISSN) ; Fray, D. J ; Sharif University of Technology
2010
Abstract
Low temperature lithium titanate compounds (i.e., Li4Ti 5O12 and Li2TiO3) with nanocrystalline and mesoporous structure were prepared by a straightforward aqueous particulate sol-gel route. The effect of Li:Ti molar ratio was studied on crystallisation behaviour of lithium titanates. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders were crystallised at the low temperature of 500 °C and the short annealing time of 1 h. Moreover, it was found that Li:Ti molar ratio and annealing temperature influence the preferable orientation growth of the lithium titanate compounds. Transmission electron microscope (TEM) images showed that the average...
Low temperature nanostructured zinc titanate by an aqueous particulate sol-gel route: Optimisation of heat treatment condition based on Zn:Ti molar ratio
, Article Journal of the European Ceramic Society ; Volume 30, Issue 4 , 2010 , Pages 947-961 ; 09552219 (ISSN) ; Fray, D. J ; Sharif University of Technology
2010
Abstract
Nanocrystalline zinc titanate (ZnTiO3) thin films and powders with purity of 94% were produced at the low sintering temperature of 500 °C and the short sintering time of 1 h by a straightforward aqueous particulate sol-gel route. The effect of Zn:Ti molar ratio was studied on the crystallisation behaviour of zinc titanates. The prepared sols showed a narrow particle size distribution in the range 17-19 nm. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders contained mixtures of the rhombohedral-ZnTiO3, cubic-ZnO, cubic-Zn2TiO4 phases, as well as the anatase-TiO2 and the rutile-TiO2 depending on the sintering temperature and Zn:Ti molar ratio....
Nanostructured TiO2-CeO2 mixed oxides by an aqueous sol-gel process: Effect of Ce:Ti molar ratio on physical and sensing properties
, Article Sensors and Actuators, B: Chemical ; Volume 150, Issue 2 , 2010 , Pages 631-640 ; 09254005 (ISSN) ; Fray, D. J ; Sharif University of Technology
2010
Abstract
Nanostructured TiO2-CeO2 thin films and powders were prepared by a straightforward aqueous particulate sol-gel route. Titanium (IV) isopropoxide and cerium chloride were used as precursors, and hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the specific surface area. The effect of Ce:Ti molar ratio was studied on the crystallisation behaviour of the products. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders crystallised at the low temperature of 500 °C, containing anatase-TiO2, rutile-TiO2 and cubic-CeO2 phases, as well as Ti 8O15, Ti3O5 and Ce 11O20 depending on annealing temperature and Ce:Ti molar...