Browsing by Author "Karlsson, Kaj H."
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- ItemEstimation of liquidus temperatures in silicate glasses(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2001) Karlsson, Kaj H.; Backman, Rainer; Cable, Michael; Peelen, Jan; Hermans, JanTwo models for estimating liquidus temperature from composition are presented and compared with thermodynamically calculated temperature as well as primary phase. Α simple polynomial model is given for high silica glasses, while a model covering a wide composition range and several primary phase fields is more complex. Thermodynamic calculations generally give too high liquidus temperatures in the devitrite field and too low in the primary field for Na2O · 2 CaO · 3 SiO2. In the wollastonite field the values are scattered, but in general too high.
- ItemProperty-composition relationships for potentially bioactive glasses(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1998) Karlsson, Kaj H.; Rönnlöf, MinnaThe compositional dependence of thermal expansion, α (in 10¯⁶ K¯¹), transformation temperature, Tg (in °C), dilatometric softening point. Mg (in °C), and viscosity, η (in dPa s), was determined for low-silica glasses in the S y s t e m Na₂O - K₂O - MgO - CaO - -Β₂O₃-Ρ₂O₅-SiO₂. The following phenomenological equations were established: α = 3.625 + 0.345p_Na₂O + 0.266p_K₂O + 0.098p_CaO + 0.064p_P₂O₅ , Tg = 635.9 - 5.26p_Na₂O + 3.18p_K₂O- 3.16p_MgO - 0.47p_Na₂O*p_K₂O - 0.12p_K₂O * p_CaO , Mg = 790.6 - 17.83p_Na₂O - 5.79p_K₂O + 0.28p²_Na₂O - 0.39p²_MgO where p_ is oxide content in wt%. The viscosity was modelled to f i t an Arrhenius-type equation, lgη = Α + B/T. Giving η in dPa s, the compositional dependence of Α and Β were found as Α = - 55.707 + 0.597p_Na₂O + 0.591p_K₂O + 0.604p_MgO + 0.516p_CaO + 0.429p_P₂O₅ + 0.387p_SiO₂, Β = - 9 1 . 4 6 3p_Na₂O + 162.861p_CaO + 485.020p_Β₂O₃ + 249.200p_P₂O₅ + 285.212p_SiO₂·