Compositions: coating or plastic – Coating or plastic compositions – Metal-depositing composition or substrate-sensitizing...
Patent
1974-10-15
1976-05-04
Douglas, Winston A.
Compositions: coating or plastic
Coating or plastic compositions
Metal-depositing composition or substrate-sensitizing...
106 53, 106 47Q, 65 30E, C03C 304
Patent
active
039544877
ABSTRACT:
A chemically hardened optical crown glass having a refractive index n.sub.d of 1.5225-1,5235, a thermal expansion coefficient in the temperature range between 20.degree. and 300.degree. C. of 90 .times. 10.sup.-.sup.7 to 100 .times. 10.sup.-.sup.7 /.degree.C., a dispersion .gamma.d of 54-60, a softening temperature of 690.degree.-750.degree. C., and a transformation temperature of 480.degree.-550.degree. C., produced by melting, shaping and cooling a batch consisting essentially of the following composition in parts by weight based on 100 parts of total composition: SiO.sub.2, 50.5-61.0; Al.sub.2 O.sub.3, 7.0-17.5; B.sub.2 O.sub.3, 2.0-6.1; Li.sub.2 O, 0-1.0; Na.sub.2 O, 12.0-15.0; K.sub.2 O, 2.5-3.5; CaO, 0-4.1; BaO, 0-0.3; ZnO, 5.0-10.0; PbO, 0-0.5; TiO.sub.2, 0.1-0.9; As.sub.2 O.sub.3, 0-0.5; and Sb.sub.2 O.sub.3, 0-1.0; and thereafter subjected to an ion exchange in which large alkali metal ions are diffused into the glass in exchange for smaller alkali metal ions at a temperature below the upper cooling temperature which corresponds to a viscosity of 10.sup.13 poises.
REFERENCES:
patent: 3301649 (1967-01-01), Marusak
patent: 3357876 (1967-12-01), Rinehart
patent: 3524737 (1970-08-01), Doyle
patent: 3740242 (1973-06-01), Faulstich
patent: 3772135 (1973-11-01), Hara
patent: 3790260 (1974-02-01), Boyd
Am. Ceramic Soc. Bull., Vol. 49, No. 11, Nov. 1970, pp. 974-977.
Gliemeroth Georg
Meckel Lothar
Douglas Winston A.
Jenaer Glaswerk Schott & Gen.
Niebling John F.
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