A lithium aluminum silicate glass ceramic, which, apart from unavoidable impurities, is As2O3-free and Sb2O3-free. The lithium aluminum silicate glass ceramic has keatite as primary crystal phase and a keatite peak temperature TP of the keatite solid solution formation in the range of 980° C. to 1090° C., and the keatite peak temperature TP is determined by dynamic differential calorimetry (DSC) in accordance with DIN 51007:2019-04 at a heating rate of 5 K/min. A ceramization method is also described.

A grain oriented electrical steel sheet includes a base steel sheet, a glass film, and a tension-insulation coating. When a glow discharge emission spectroscopy is conducted from a surface of the glass film toward a depth direction, an analysis starting time Ts, a time T.sup.Al.sub.p at which Al shows a maximum emission intensity, an Al emission intensity F(T.sup.Al.sub.p) at the T.sup.Al.sub.p, a time T.sup.Si.sub.p at which Si shows a maximum emission intensity, and an Al emission intensity F(T.sup.Si.sub.p) at the T.sup.Si.sub.p satisfy 0.05≤F(T.sup.Si.sub.p)/F(T.sup.Al.sub.p)≤0.50 and 2.0≤(T.sup.Al.sub.p−Ts)/(T.sup.Si.sub.p−Ts)≤5.0.

A lithium silicate glass ceramic having lithium metasilicate as main crystal phase and having not more than 30 wt.-% of lithium metasilicate crystals and having the following components in the amounts indicated:

TABLE-US-00001 Component Wt.-% SiO.sub.2 71.0 to 82.0 Li.sub.2O 6.0 to 14.0 Me.sup.I.sub.2O 4.0 to 15.0 Al.sub.2O.sub.3 2.0 to 10.0 P.sub.2O.sub.5 0.5 to 7.0,
wherein Me.sup.I.sub.2O is selected from Na.sub.2O, K.sub.2O, Rb.sub.2O, Cs.sub.2O and mixtures thereof, and
wherein the molar ratio of SiO.sub.2 to Li.sub.2O is in the range of 2.5 to 5.0.

A lithium silicate glass ceramic having lithium metasilicate as main crystal phase and having not more than 30 wt.-% of lithium metasilicate crystals.

A method for melting and/or refining glass, glass ceramic or glass which can be ceramized to form glass ceramic includes: providing a batch of raw materials; heating the batch until a melt of molten glass is obtained, the batch being heated at least in sections to a temperature above T3 which corresponds to a viscosity of the molten glass of 10.sup.3 dPa*s; refining the melt, the melt being heated at least in sections to a temperature above T2.5 which corresponds to a viscosity of the molten glass of 10.sup.2.5 dPa*s, refining of the melt includes adjusting an oxygen partial pressure p(O.sub.2) which is reduced by at least 60% relative to an O.sub.2 saturation in the melt at temperature T3; and obtaining a re-fined glass, a refined glass ceramic or a refined glass which can be ceramized to form glass ceramic.

The present invention provides a silicate glass that can reduce a color change in base material zirconia even when simultaneously fired with an unsintered zirconia. The present invention also provides a dental product using same. The present invention relates to a silicate glass comprising: 65.0 to 90.0 mol % SiO.sub.2, 4.0 to 15.0 mol % Al.sub.2O.sub.3, 1.0 to 10.0 mol % K.sub.2O, 0.1 to 7.0 mol % Na.sub.2O, and 0.01 to 15.0 mol % CaO, the silicate glass being essentially free of B.sub.2O.sub.3, and satisfying the relation {(number of moles of Al.sub.2O.sub.3)/(total number of moles of RO+R.sub.2O)}≥0.70, wherein R in the metal oxide represented by RO represents a metallic element in group 2 or 12 of the periodic table, and R in the metal oxide represented by R.sub.2O represents a metallic element in group 1 of the periodic table. The present invention also relates to a composite comprising the silicate glass and a base material formed of a ceramic; a sintered body as a fired product of the composite; and a dental product comprising the sintered body.

A glass-ceramic comprising, in weight percent on an oxide basis, of 50 to 70% SiO.sub.2, 0 to 20% Al.sub.2O.sub.3, 12 to 23% MgO, 0 to 4% Li.sub.2O, 0 to 10% Na.sub.2O, 0 to 10% K.sub.2O, 0 to 5% ZrO.sub.2, and 2 to 12% F, wherein the predominant crystalline phase of said glass-ceramic is a trisilicic mica, a tetrasilicic mica, or a mica solid solution between trisilicic and tetrasilicic, and wherein the total of Na.sub.2O+Li.sub.2O is at least 2 wt. %; wherein the glass-ceramic can be ion-exchanged.

Optically transparent glass ceramic materials comprising a glass phase containing and a crystalline tungsten bronze phase comprising nanoparticles and having the formula M.sub.xWO.sub.3, where M includes at least one H, Li, Na, K, Rb, Cs, Ca, Sr, Ba, Zn, Cu, Ag, Sn, Cd, In, Tl, Pb, Bi, Th, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, and U, and where 0<x<1. Aluminosilicate and zinc-bismuth-borate glasses comprising at least one of Sm.sub.2O.sub.3, Pr.sub.2O.sub.3, and Er.sub.2O.sub.3 are also provided.

Disclosed in the present invention is a beam coherence eliminating element. The optical medium material of the element comprises microcrystalline glass, wherein microcrystalline particles therein have a size of 0.1-1000 nm and are distributed randomly. As the crystals in the microcrystalline glass can change the phase of light beams, the microcrystalline glass can change the phase of the light beams randomly, thereby eliminating the coherence of the beams. The crystal size of the microcrystalline glass is small, and thus does not affect the transmission efficiency of light beams. The element of the present invention has a simple structure and is convenient to use, and can be added in the process of beam transmission to easily eliminate beam coherence.

A tubular member for an exhaust gas treatment device according to at least one embodiment of the present invention includes: a tubular main body made of a metal; and an insulating layer formed at least on an inner peripheral surface of the tubular main body. The insulating layer contains glass containing a crystalline substance, and the glass contains silicon, boron, and magnesium.