The present invention relates to a particle mixture comprising particles of glass frit and particles of a crystalline oxide material, wherein the glass frit comprises silicon oxide (SiO.sub.2), zinc oxide (ZnO) and sulfur (S) and wherein the D90 particle size of the particle mixture is less than 5 microns. The particle mixture may be used to apply an enamel to a substrate. The present invention further relates to the use of the particle mixture to form an enamel on a substrate, to a glass sheet and to an automotive window pane.

The present invention relates to a particle mixture comprising particles of glass frit and particles of a crystalline oxide material, wherein the glass frit comprises silicon oxide (SiO.sub.2), zinc oxide (ZnO) and sulfur (S) and wherein the D90 particle size of the particle mixture is less than 5 microns. The particle mixture may be used to apply an enamel to a substrate. The present invention further relates to the use of the particle mixture to form an enamel on a substrate, to a glass sheet and to an automotive window pane.

Producing a molded body made of opaque quartz glass includes providing SiO.sub.2 grains obtained by comminuting quartz glass having a purity of at least 99.9 wt % SiO.sub.2, forming a slurry containing a suspension liquid and the SiO.sub.2 grains and which has a total solids content, wet grinding the SiO.sub.2 grains in the slurry so as to form ground SiO.sub.2 grain particles, forming a porous green body from the slurry, and sintering the porous green body. To provide a low cost quartz glass, the wet grinding of the SiO.sub.2 grains takes place at least temporarily in the presence of SiO.sub.2 nanoparticles, the proportion of which in the total solids content of the slurry is in the range of 0.1 wt % to 10 wt %, and the slurry has a solids content in the range of 76 to 80 wt % after addition of the SiO.sub.2 nanoparticles and after the wet grinding.

Producing a molded body made of opaque quartz glass includes providing SiO.sub.2 grains obtained by comminuting quartz glass having a purity of at least 99.9 wt % SiO.sub.2, forming a slurry containing a suspension liquid and the SiO.sub.2 grains and which has a total solids content, wet grinding the SiO.sub.2 grains in the slurry so as to form ground SiO.sub.2 grain particles, forming a porous green body from the slurry, and sintering the porous green body. To provide a low cost quartz glass, the wet grinding of the SiO.sub.2 grains takes place at least temporarily in the presence of SiO.sub.2 nanoparticles, the proportion of which in the total solids content of the slurry is in the range of 0.1 wt % to 10 wt %, and the slurry has a solids content in the range of 76 to 80 wt % after addition of the SiO.sub.2 nanoparticles and after the wet grinding.

A glass composition includes greater than or equal to 60 mol % and less than or equal to 85 mol % SiO.sub.2; greater than or equal to 0.5 mol % and less than or equal to 20 mol % Al.sub.2O.sub.3; greater than or equal to 0 mol % and less than or equal to 15 mol % Li.sub.2O; greater than or equal to 0.5 mol % and less than or equal to 25 mol % Na.sub.2O; greater than or equal to 0.1 mol % and less than or equal to 20 mol % 1(20; greater than or equal to 0 mol % and less than or equal to 10 mol % CaO; greater than or equal to 0 mol % and less than or equal to 10 mol % MgO; and greater than or equal to 0.005 mol % and less than or equal to 0.5 mol % Au.

A glass composition includes greater than or equal to 60 mol % and less than or equal to 85 mol % SiO.sub.2; greater than or equal to 0.5 mol % and less than or equal to 20 mol % Al.sub.2O.sub.3; greater than or equal to 0 mol % and less than or equal to 15 mol % Li.sub.2O; greater than or equal to 0.5 mol % and less than or equal to 25 mol % Na.sub.2O; greater than or equal to 0.1 mol % and less than or equal to 20 mol % 1(20; greater than or equal to 0 mol % and less than or equal to 10 mol % CaO; greater than or equal to 0 mol % and less than or equal to 10 mol % MgO; and greater than or equal to 0.005 mol % and less than or equal to 0.5 mol % Au.

The present invention relates to a spinel glass-ceramic made from a composition with the components 25 to 50% by weight SiO.sub.2, 10 to 35% by weight Al.sub.2O.sub.3, 1 to 15% by weight MgO, 1 to 15% by weight P.sub.2O.sub.5, 1 to 25% by weight ZrO.sub.2 and/or TiO.sub.2, 0 to 20% by weight La.sub.2O.sub.3, 0 to 10% by weight B.sub.2O.sub.3, and 0 to 15% by weight additives. The spinel glass-ceramic contains at least one spinel phase, but no high quartz solid solution phase. The glass-ceramic according to the invention exhibits very high mechanical stability, for example, very high flexural strength, wherein its optical properties can be simultaneously adjusted. In addition, the present invention also relates to a method for producing and the use of the spinel glass-ceramic. Furthermore, the present invention relates to a shaped dental product containing the spinel glass-ceramic.

The present invention relates to a spinel glass-ceramic made from a composition with the components 25 to 50% by weight SiO.sub.2, 10 to 35% by weight Al.sub.2O.sub.3, 1 to 15% by weight MgO, 1 to 15% by weight P.sub.2O.sub.5, 1 to 25% by weight ZrO.sub.2 and/or TiO.sub.2, 0 to 20% by weight La.sub.2O.sub.3, 0 to 10% by weight B.sub.2O.sub.3, and 0 to 15% by weight additives. The spinel glass-ceramic contains at least one spinel phase, but no high quartz solid solution phase. The glass-ceramic according to the invention exhibits very high mechanical stability, for example, very high flexural strength, wherein its optical properties can be simultaneously adjusted. In addition, the present invention also relates to a method for producing and the use of the spinel glass-ceramic. Furthermore, the present invention relates to a shaped dental product containing the spinel glass-ceramic.

A glass-ceramic article comprises a petalite crystalline phase and a lithium silicate crystalline phase. The weight percentage of each of the petalite crystalline phase and the lithium silicate crystalline phase in the glass-ceramic article are greater than each of the weight percentages of other crystalline phases present in the glass-ceramic article. The glass-ceramic article has a transmittance color coordinate in the CIELAB color space of: L*=from 20 to 90; a*=from −20 to 40; and b*=from −60 to 60 for a CIE illuminant F02 under SCI UVC conditions. In some embodiments, the colorant is selected from the group consisting of TiO.sub.2, Fe.sub.2O.sub.3, NiO, Co.sub.3O.sub.4, MnO.sub.2, Cr.sub.2O.sub.3, CuO, Au, Ag, and V.sub.2O.sub.5.

A glass-ceramic article comprises a petalite crystalline phase and a lithium silicate crystalline phase. The weight percentage of each of the petalite crystalline phase and the lithium silicate crystalline phase in the glass-ceramic article are greater than each of the weight percentages of other crystalline phases present in the glass-ceramic article. The glass-ceramic article has a transmittance color coordinate in the CIELAB color space of: L*=from 20 to 90; a*=from −20 to 40; and b*=from −60 to 60 for a CIE illuminant F02 under SCI UVC conditions. In some embodiments, the colorant is selected from the group consisting of TiO.sub.2, Fe.sub.2O.sub.3, NiO, Co.sub.3O.sub.4, MnO.sub.2, Cr.sub.2O.sub.3, CuO, Au, Ag, and V.sub.2O.sub.5.