To provide a glass plate for a window material and a window comprising the glass plate, which are less likely to be a barrier to radio transmitting/receiving in use of a radio-utilizing apparatus, and a radio communication apparatus comprising the glass plate.

A glass plate having a radio transmittance of at least 20% at a frequency of 100 GHz as calculated as 18 mm thickness, a window comprising the glass plate, and a radio communication apparatus comprising the glass plate.

A support glass substrate of the present invention is a support glass substrate for supporting a substrate to be processed, the support glass substrate including lithium aluminosilicate-based glass, having a content of Li.sub.2O of from 0.02 mol % to 25 mol % in a glass composition, and having an average linear thermal expansion coefficient within a temperature range of from 30° C. to 380° C. of 38×10.sup.−7/° C. or more and 160×10.sup.−7/° C. or less.

A support glass substrate of the present invention is a support glass substrate for supporting a substrate to be processed, the support glass substrate including lithium aluminosilicate-based glass, having a content of Li.sub.2O of from 0.02 mol % to 25 mol % in a glass composition, and having an average linear thermal expansion coefficient within a temperature range of from 30° C. to 380° C. of 38×10.sup.−7/° C. or more and 160×10.sup.−7/° C. or less.

A method of forming a glass sheet comprises: (a) forming a ribbon of glass from molten glass with a pair of forming rollers; (b) reducing horizontal temperature variability of the ribbon of glass to be 10° C. or less across 80 percent of an entire width of the ribbon of glass before the ribbon of glass cools to a glass transition temperature; (c) controlling a cooling rate of the ribbon of glass while the ribbon of glass moves vertically downward within a setting zone such that the ribbon of glass has a first average cooling rate before the ribbon of glass cools to the glass transition temperature and a second average cooling rate after the ribbon of glass cools to the glass transition temperature, the first average cooling rate being less than the second average cooling rate; and (d) separating a glass sheet from the ribbon of glass.

A soda lime glass plate has, on the basis of oxides, a total sulfur content in terms of SO.sub.3 of 0.001 to 0.2% in mass %, a total iron content in terms of Fe.sub.2O.sub.3 of 0.15 to 0.4% in mass %, and a total tin content in terms of SnO.sub.2 of 0.02 to 1% in mass %, and has a mass proportion of a divalent iron in terms of Fe.sub.2O.sub.3 in the total iron in terms of Fe.sub.2O.sub.3 of 45 to 70%. The soda lime glass plate has, as a conversion value for a 3.85 mm-thickness glass plate, a visible light transmittance Tv_A of 70% or more, a total solar transmittance Tts of 63.7% or less, and c* in the L*a*b* color space of 4 or less.

A soda lime glass plate has, on the basis of oxides, a total sulfur content in terms of SO.sub.3 of 0.001 to 0.2% in mass %, a total iron content in terms of Fe.sub.2O.sub.3 of 0.15 to 0.4% in mass %, and a total tin content in terms of SnO.sub.2 of 0.02 to 1% in mass %, and has a mass proportion of a divalent iron in terms of Fe.sub.2O.sub.3 in the total iron in terms of Fe.sub.2O.sub.3 of 45 to 70%. The soda lime glass plate has, as a conversion value for a 3.85 mm-thickness glass plate, a visible light transmittance Tv_A of 70% or more, a total solar transmittance Tts of 63.7% or less, and c* in the L*a*b* color space of 4 or less.

A glass for magnetic recording medium substrate is an amorphous oxide glass. In terms of mol %, SiO.sub.2 content ranges from 45 to 68%, Al.sub.2O.sub.3 from 5 to 20%, total content of SiO.sub.2 and Al.sub.2O.sub.3 60 to 80%, B.sub.2O.sub.3 from 0 to 5%, MgO from 3 to 28%, CaO from 0 to 18%, total content of BaO and SrO 0 to 2%, total content of alkali earth metal oxides from 12 to 30%, total content of alkali metal oxides from 3.5 to 15%, and at least one kind selected from the group made of Sn oxide and Ce oxide being included, a total content of Sn oxide and Ce oxide ranges from 0.05 to 2.00%, a glass transition temperature ≥625° C., a Young's modulus ≥83 GPa, a specific gravity ≤2.85, and an average linear expansion coefficient at 100 to 300° C.≥48×10.sup.−7/° C.

Articles may be protected against halide plasma, by applying a rare earth-containing glaze to the surface of the article. The glaze may be a coating comprising; 20 to 90 mol % SiO.sub.2, 0 to 60 mol % Al.sub.2O.sub.3, 10 to 80 mol % rare earth oxides and/or rare earth fluorides (REX), wherein SiO.sub.2+Al.sub.2O.sub.3+REX≥60 mol %.

Articles may be protected against halide plasma, by applying a rare earth-containing glaze to the surface of the article. The glaze may be a coating comprising; 20 to 90 mol % SiO.sub.2, 0 to 60 mol % Al.sub.2O.sub.3, 10 to 80 mol % rare earth oxides and/or rare earth fluorides (REX), wherein SiO.sub.2+Al.sub.2O.sub.3+REX≥60 mol %.

A paste for ceramic 3D shaping according to the present invention is a paste for ceramic 3D shaping containing a curable resin and inorganic particles, in which the inorganic particles contain ceramic particles and glass particles.