Schott Glaswerke

Jenaer Glaswerk Schott & Gen.

Werner Sack

Herwig Scheidler

Werner Kiefer

Otto Lindig

Alkali-free glasses with low dielectric losses, thermal expansion coefficients of 3.15 to 4.97.times.10.sup.-6 /.degree.C. in the temperature range from 20.degree. to 300.degree. C., adequate acid resistance, dielectric loss factors tan .delta. of 3.94 to 24.9.times.10.sup.-4 and processing temperatures (V.sub.A) of 1132.degree. to 1280.degree. C., have the following composition (in weight percent): 52.50-60.20 SiO.sub.2, 2.80-3.80 B.sub.2 O.sub.3, 8-14 Al.sub.2 O.sub.3, 6.0-20.20 PbO, 2.0-13.5 CaO, 0-3.5 MgO, 0-8 ZnO, 0-4.7 BaO, .SIGMA.PbO, CaO, MgO, ZnO, BaO 21.10-34.0, 0-1.0 F, 0.20-0.50 Sb.sub.2 O.sub.3.

Glass compositions with low dielectric losses

New, PbO-free glasses for cathode ray tubes are composed of (in % by weight) 50-52 SiO.sub.2 ; 0-3 Al.sub.2 O.sub.3 ; 1-1.7 Li.sub.2 O; 6.5-10.7 Na.sub.2 O; 0-4.5 K.sub.2 O; 0.4-1.4 F; 0-0.5 TiO.sub.2 ; 0.2-1.2 CeO.sub.2 ; 0-5 ZnO; 0-7.0 BaO; 15-22 SrO; and 6.3-10.3 ZrO.sub.2, and are characterized by a high protective effect against X-rays while having at the same time good resistance to acid and stability to radiation.

PbO-free glasses for cathode ray tubes having a high protective effect

Partially crystallizing glass solders, and stripping films using them as agents to be transferred, which are sintered at temperatures below 900.degree. C. from glass powder with granulation of less than &lt;150 .mu.m, thereafter exhibiting thermal expansion coefficients of -23.5 to 34.3.sup..multidot. 10.sup.-7.multidot. K.sup.-1, whose crystallization temperature lies below 710.degree. C. and whose crystal phase consists predominantly of h-quartz mixed crystal phase exhibiting the following composition (in weight %): 23-44 SiO.sub.2, 20-37 Al.sub.2 O.sub.3, 5.5-11 Li.sub.2 O; 3-20 B.sub.2 O.sub.3 ; 0-36 PbO; 0-1 Na.sub.2 O; 0-1.5 K.sub.2 O; 0-0.1 F; 0-4 TiO.sub.2 ; 0-3.5 MgO; 0-2 CoO, provided B.sub.2 O.sub.3 +PbO+Na.sub.2 O+K.sub.2 O+F+TiO.sub.2 is 8.5-50.0.

Crystallizing glass solders and stripping films with such glass solder

A fusion glass of the series SiO.sub.2 --Al.sub.2 O.sub.3 --Na.sub.2 O--PbO--Fe.sub.3 O.sub.4 consists essentially of 43.0-46.2% by weight of SiO.sub.2 ; 1.0-2.0% by weight of Al.sub.2 O.sub.3 ; 6.2-16.0% by weight of Na.sub.2 O; 33.0-46.1% by weight of PbO; 2.0-4.5% by weight of Fe.sub.3 O.sub.4 ; and a maximum of 0.2% by weight of Sb.sub.2 O.sub.3, all calculated as percent by weight of oxide. These heat-absorbing fusion glasses having a low softening point can be used especially for the hermetic encapsulation of electrotechnical components, especially of conductor contacts operated magnetically as well as nonmagnetically, having coefficients of thermal expansion in the temperature range of 20.degree.-300.degree. C. of about 8.4-12.2.times.10.sup.-6 /.degree.C. and maximum heat absorption at about 1 to 1.5 .mu.m. These glasses have softening temperatures (ST) of about 537.degree. to 601.degree. C., processing temperatures (PT) of about 763.degree. to 879.degree. C., and a lower tendency toward varporization during the fusion process. The fusion stresses between the metallic conductor and the glass, existing after the fusion process and occurring upon rapid cooling in air and after a 5.degree. C./min cooling step, are characterized by a maximum tensile stress corresponding to an optical path difference of .ltoreq.400 nm/cm, at a specific birefringence of about (2.7.+-.0.1).times.10.sup.-6 mm.sup.2 /N.

Crack-resistant, heat-absorbing fusion glasses enabling low processing

SiO.sub.2 -Al.sub.2 O.sub.3 -alkaline earth oxides glass compositions suitable for glass/molybdenum sealings with high thermal load capability, having coefficients of thermal expansion in the temperature range of 20.degree.-300.degree. C. of 4.6-5.1.times.10.sup.-6 /.degree. C., glass transformation temperatures (Tg) of 775.degree.-810.degree. C., softening temperatures (Ew) greater than 930.degree. C., processing temperatures (V.sub.A) of 1232.degree.-1273.degree. C. and at length of V.sub.A -Ew greater than 300.degree. C. as regards processing technology of these glasses in the mixture, which consist essentially of the following components, computed as percent by oxide weight:

Alkali-free sealing glasses for molybdenum

Glass compositions have been found which, with a low linear thermal expansion coefficient of 33.9-53.2.times.10.sup.-7 /.degree.C. at 20-300.degree. C. will pre-stress to a much higher extent under similar prestressing conditions than known glasses of the same thermal expansion, and which consequently result in crumbling under forced fracture. The glasses possess the following properties: the transformation temperatures (Tg) are between 566.degree. and 660.degree. C., the softening temperatures (Ew) are between 821.degree. and 845.degree. C. and working temperatures are between 1211.degree. and 1370.degree. C., the temperature differential Ew-Tg being 232.degree. to 298.degree. C., the ratio .alpha.'/.alpha. of the thermal expansion coefficient above Tg (.alpha.') to expansion below Tg (.alpha.) being between 4.1 and 9.4 and the formation comprising:

Thermally high pre-stressable glass with high hot stressing factors

Glass ceramic and the process for producing a dark red glass ceramic comprising the production of basic glass by melting at about 1620.degree. C a mixture of approximate percentages of sand 53.30%, hydrated alumina 27.15%, zirconium silicate 1.90%, titanium oxide 2.02%, lithium carbonate 7.49%, sodium carbonate 0.87%, potash 0.62%, dolomite 0.39%, barium carbonate 1.04%, barium nitrate 2.16%, zinc oxide 1.09%, manganese dioxide 0.56%, ferric oxide 0.21%, cobalt oxide 0.36%, nickel oxide 0.05% and antimony oxide 0.73%. After cooling to about 1480.degree. C, the glass is formed into articles, and the articles further cooled to at least 700.degree. C. The articles are then heat treated to 800.degree. C at about .ltoreq.10.degree. C/min., devitrifying the glass from 800.degree. C to 900.degree. C, at, for example, 0.5.degree. C/min and cooling the article from 890.degree. C to room temperature at, for example, 7.degree. C/min.

Dark red transparent refractory glass

A glass having a softening temperature (E.sub.W) between 596.degree. and 634.degree. C. and a working temperature (V.sub.A) between 792.degree. and 863.degree. C., said glass being produced from a melt having a composition expressed in percentages by weight as follows:

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