Micaceous-cordierite-glass ceramic

摘要

Micaceous-cordierite-glass ceramic particularly suitable for stomatological, head surgery and neck surgery applicatiosn has a fracture toughness KIC of up to 2.0 MPa m1/2, a hardness HV0.07 of 300-1000, a compressive strength of up to 450 N/mm2, a linear thermal expansion coefficient of 75-125x10-7 K-1, good chemical stability and excellent machinability as well as a high resistance to wear and comprises a composition in weight percentages of -SiO2 43-50 -Al2O3 26-30 -MgO 11-15 -R2O 7-10.5 -F- 3.3-4.8 -Cl- 0.01-0.6 -CaO 0.1-3 -P2O5 0.1-5 - wherein R2O is the sum of 3 to 5.5 wt. % Na2O and 4 to 6 wt. % K2O, a first crystal phase of mica, and a second crystal phase of 5 to 30 volume % cordierite, wherein relatively large mica crystals of 10 to 200 mu m are embedded in the glass and cordierite crystals of 0.5 to 5 mu m are arranged in the glass.