Synthesis of glass‐ceramics in the Na <sub>2</sub> O/K <sub>2</sub> O‐CaO‐MgO‐SiO <sub>2</sub> ‐P <sub>2</sub> O <sub>5</sub> ‐CaF <sub>2</sub> system as candidate materials for dental applications
Konstantinos Dimitriadis, Konstantinos C. Vasilopoulos, Tiverios Vaimakis, Michael A. Karakassides, Dilshat U. Tulyaganov, Simeon Agathopoulos
Abstract
Abstract This study reports on the sintering behavior, crystallization process, and mechanical properties of novel glass‐ceramics (CGs) produced by the glass powder compact consolidation method. Substitution of K 2 O for Na 2 O and MgO for CaO was attempted in the parent glasses belonging to Na 2 O‐CaO‐MgO‐SiO 2 ‐P 2 O 5 ‐CaF 2 system. Glass powder compacts were heat treated at various temperatures between 700°C and 900°C, taking under consideration the glass transition ( T g ) and the crystallization peak ( T p ) temperatures, which were experimentally determined for each investigated glass by thermal analysis (dilatometry and differential scanning calorimetry). The experimental results showed that sintering always preceded crystallization, regardless of the type of substitution. In the case of MgO substitution for CaO, crystallization was advanced in the range of 800°C‐850°C, resulting in the formation of an assembly of crystalline phases, such as diopside, fluorapatite, and wollastonite. The substitution of K 2 O for Na 2 O increased the activation energy for crystallization, shifting crystallization process to a high temperature region, with the formation of alpha‐potassium magnesium silicate, instead of wollastonite. The GCs produced had values of 22‐31 GPa regarding the modulus of elasticity, 5.0‐6.1 GPa concerning the microhardness, and 1.4‐1.9 MPa⋅m 0.5 as regard the fracture toughness, which are similar to those of the human jawbone.