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The Effect of Nano-TiO2 and CaF2 Additives on Formulation and Properties of SiO2-Li2O Glass-Ceramics

Gol, Saba | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48512 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Nemati, Ali
  7. Abstract:
  8. 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 resistance, flectural strength and hardness of samples were evaluated. The results of thermal analysis, phase analysis, and microstructural studies showed that the presence of CaF2 causes the formation of interlocked rod-like lithium disilicate crystals in the glass matrix. The sample containing 1 %Wt CaF2 indicated best results. On the other hand, the presence of nan-TiO2 causes the formation of spherical lithium disilicate crystals. The dominant crystallization mechanism in the presence of these additives was volume crystallization. These additives also increased the amount of lithium disilicate phase which resulted in improvement of mechanical properties compared to base glass-ceramic
  9. Keywords:
  10. Glass-Ceramic ; Nucleation ; Titanium Dioxide Nanoparticles ; Silicon Dioxide ; Calcium Fluoride ; Lithium-Disilicate

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