| abstract |
The invention relates to a glass ceramic, wherein the initial glass comprises 30-65 percent (by weight) SiO 2 ; 5-30 percent (by weight) Na 2 O; 5-30 percent (by weight) CaO, and 0-15 percent (by weight) P 2 O 5 , and wherein the main crystalline phases comprise alkali-alkaline earth-silicate and/or alkali silicate and/or alkaline earth silicate. The invention is characterized in that either a glass ceramic with a single crystalline phase 1 Na 2 O-2 CaO-3 SiO 2 is excluded, or the crystalline size of the glass ceramic is <10 μm, or the weight fraction of SiO 2 is <47%. |