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The Effect of Nano-TiO2 and CaF2 Additives on Formulation and Properties of SiO2-Li2O Glass-Ceramics
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor)
Abstract
The goal of the present study is to analyze the effect of CaF2 and nano-TiO2 as additives on formulation and properties of common dental glass-ceramics. To achieve the goal, a glass system based on SiO2-Al2O3-Li2O-K2O-P2O5-ZnO-ZrO2 was considered to produce glass-ceramic samples and the additives, nano-TiO2 and CaF2, with the 0.5, 1, and 1.5 %Wt was added to the system. After the melting process, the glass samples poured in the water and ferrite was produced. In the next step, the ferrite was milled and pressed. In the heat treatment step, the samples were treated in the temperature range of 650-850°C in order to gain lithium disilicate glass-ceramics. In the last step, the chemical...
Mechanism of nanostructured fluorapatite formation from CaO, CaF2 and P2O5 precursors by mechanochemical synthesis
, Article Progress in Reaction Kinetics and Mechanism ; Volume 43, Issue 3-4 , 2018 , Pages 201-210 ; 14686783 (ISSN) ; Sadrnezhaad, S. K ; Vahdati Khaki, J ; Sharif University of Technology
Science Reviews 2000 Ltd
2018
Abstract
We determined the mechanism of mechanochemical synthesis of fluorapatite from CaO, CaF2 and P2O5 by characterisation of the intermediate compounds. We used atomic absorption spectroscopy, X-ray diffraction, field emission scanning electron microscopy, FTIR spectroscopy and transmission electron microscopy to find the transitional compounds. Investigation of the binary and ternary powder mixtures revealed the appearance of H3PO4, Ca(OH)2, Ca2P2O7 and CaCO3 as the intermediate compounds. At early stages of the milling, conversions of P2O5 to H3PO4 and CaO to Ca(OH)2 occurred in the wet atmosphere. Later, a combination of Ca(OH)2 and H3PO4 formed Ca2P2O7 while the unreacted CaO was converted to...
Enhanced TiO2broadband photocatalytic activity based on very small upconversion nanosystems
, Article Journal of Physical Chemistry C ; Volume 125, Issue 25 , 2021 , Pages 13788-13801 ; 19327447 (ISSN) ; Madaah Hosseini, H. R ; Mohajerani, E ; Pedroni, M ; Taheri Ghahrizjani, R ; Sharif University of Technology
American Chemical Society
2021
Abstract
Efficient sunlight harvesting is of great significance for environmental remediation through photocatalysis. Herein, very small (20 nm) upconverter SrF2:Yb,Tm@CaF2:Yb@Fluorine-doped TiO2heteronanoparticles (denoted as UCNPs@TiO2) with strong UV-blue emission and broadband photocatalytic performance were prepared via a facile three-step hydrothermal method for the first time. The SrF2:Yb,Tm upconverter nanoparticles (NPs) were produced as the light-emitting core, epitaxially grown CaF2:Yb as the middle shell to enhance the upconversion luminescence output and TiO2as the photocatalyst outermost layer. Superior photocatalytic functioning of UCNPs@TiO2was affirmed through methylene blue (MB)...