The present invention is directed to a process for producing a sintered lithium disilicate glass ceramic dental restoration out of a porous 3-dim article, the process comprising the step of sintering the porous 3-dim article having the shape of a dental restoration with an outer and inner surface to obtain a sintered lithium disilicate ceramic dental restoration, the sintered lithium disilicate glass ceramic dental restoration comprising Si oxide calculated as SiO2 from 55 to 80 wt.-%, Li oxide calculated as Li2O from 7 to 16 wt.-%, Al oxide calculated as Al2O3 from 1 to 5 wt.-%, and P oxide calculated as P2O5 from 1 to 5 wt.-%, wt.-% with respect to the weight of the dental restoration,
the sintering being done under reduced atmospheric pressure conditions, the reduced atmospheric pressure conditions being applied at a temperature above 600° C.

The present invention is also directed to a kit of parts comprising a porous 3-dim article having the shape of a dental milling block and a respective instruction of use.

The present invention pertains to a glass for strengthening, that: has an average transmittance of at least 70% when converted to a thickness of 0.8 mm at a wavelength of 380-780 nm; has a haze value of no more than 0.7% when converted to a thickness of 0.8 mm in a C light source; has a Young's modulus of at least 85 GPa; has a fracture toughness value of at least 0.90 MPa.Math.m.sup.1/2; a thermal conductivity at 20° C. of at least 1.3 W/m.Math.K; and comprises a lithium aluminosilicate crystallized glass.

Transparent, dyed cook top or hob with improved color display capability, consisting of a glass ceramic with high quartz mixed crystals as predominant crystal phase, whereby the glass-ceramic contains none of the chemical refining agents arsenic oxide and/or antimony, with transmission values of greater than 0.1% in the range of the visible light within the entire wavelength range greater than 450 nm, a light transmission in the visible of 0.8-2.5% and a transmission in the infrared at 1600 nm of 45-85%.

A glass-ceramic includes a silicate-containing glass and crystals within the silicate-containing glass. The crystals include non-stoichiometric tungsten and/or molybdenum sub-oxides, and the crystals are intercalated with dopant cations.

In embodiments, a precursor glass composition comprises from about 55 wt. % to about 80 wt. % SiO.sub.2; from about 2 wt. % to about 20 wt. % Al.sub.2O.sub.3; from about 5 wt. % to about 20 wt. % Li.sub.2O; greater than 0 wt % to about 3 wt. % Na.sub.2O; a non-zero amount of P.sub.2O.sub.5 less than or equal to 4 wt. %; and from about 0.2 wt. % to about 15 wt. % ZrO.sub.2. In embodiments, ZrO.sub.2 (wt. %)+P.sub.2O.sub.5 (wt. %) is greater than 3. When the precursor glass composition is converted to a glass-ceramic article, the glass-ceramic article may include grains having a longest dimension of less than 100 nm.

A glass ceramic article including a lithium disilicate crystalline phase, a petalite crystalline phased, and a residual glass phase. The glass ceramic article has a warp (μm)<(3.65×10.sup.−9/μm×diagonal.sup.2) where diagonal is a diagonal measurement of the glass ceramic article in μm, a stress of less than 30 nm of retardation per mm of glass ceramic article thickness, a haze (%)<0.0994t+0.12 where t is the thickness of the glass ceramic article in mm, and an optical transmission (%)>0.91×10.sup.(2-0.03t) of electromagnetic radiation wavelengths from 450 nm to 800 nm, where t is the thickness of the glass ceramic article in mm.

Ion-exchanged glass ceramic articles described herein have a stress that decreases with increasing distance according to a substantially linear function from a depth of about 0.07 t to a depth of about 0.26 t from the outer surface of the ion-exchanged glass ceramic article from a compressive stress to a tensile stress. The stress transitions from the compressive stress to the tensile stress at a depth of from about 0.18 t to about 0.25 t from the outer surface of the ion-exchanged glass ceramic article. An absolute value of a maximum compressive stress at the outer surface of the ion-exchanged glass article is from 1.8 to 2.2 times an absolute value of a maximum central tension (CT) of the ion-exchanged glass article, and the glass ceramic article has a fracture toughness of 1 MPa√m or more as measured according to the double cantilever beam method.

Reinforced crystallized glass characterized including crystallized glass as a base material, the crystallized glass containing, as expressed in terms of mol % on an oxide basis, 30.0% to 70.0% of an SiO.sub.2 component, 8.0% to 25.0% of an Al.sub.2O.sub.3 component, 2.0% to 25.0% of an Na.sub.2O component, 1.0% to 6.0% of an Li.sub.2O component, 0 % to 25.0% of an MgO component, 0% to 30.0% of a ZnO component, and 0% to 10.0% of a TiO.sub.2 component, in which a surface of the reinforced crystallized glass is formed with a compressive stress layer, and a depth (DOLzero) of the compressive stress layer is 60 μm or more.

A transparent article is described herein that includes: a glass-ceramic substrate comprising first and second primary surfaces opposing one another and a crystallinity of at least 40% by weight; and an optical film structure disposed on the first primary surface. The optical film structure comprises a plurality of alternating high refractive index (RI) and low RI layers and a scratch-resistant layer. The article also exhibits an average photopic transmittance of greater than 80% and a maximum hardness of greater than 10 GPa, as measured by a Berkovich Hardness Test over an indentation depth range from about 100 nm to about 500 nm. The glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa.Math.√m. Further, the optical film structure exhibits a residual compressive stress of ≥ 700 MPa and an elastic modulus of ≥140 GPa.

The present invention relates to a method of producing a chemically strengthened glass, the method including chemically strengthening a lithium aluminosilicate glass having a thickness of t [unit: μm], in which the lithium aluminosilicate glass has a fracture toughness value (K1c) of 0.80 MPa.Math.m′.sup.12 or more, the chemical strengthening is chemical strengthening with a strengthening salt including sodium and having a potassium content of less than 5 mass %, and a chemically strengthened glass to be obtained has a surface compressive stress value (CS.sub.0) of 500-1,000 MPa and has a depth DOL [unit: μm] at which a compressive stress value is zero of 0.06 t to 0.2 t.