The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 17, 1976
Filed:
Aug. 26, 1974
Applicant:
Inventor:
Merritt J Hummel, Lower Burrell, PA (US);
Assignee:
PPG Industries, Inc., Pittsburgh, PA (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C03B / ;
U.S. Cl.
CPC ...
65 33 ; 106 397 ;
Abstract
Crystallized glass has hitherto been made by the use of the mineral petalite as the source of lithium values. Petalite is in short supply, and when attempts are made to use lithium carbonate or a similar lithium salt in place of petalite in the glass batch, unwanted microcracking develops during a subsequent crystallizing heat treatment with certain glass compositions. Such microcracking can be avoided by using a purposefully small addition to the petalite-free batch of an alkali metal salt, wherein the alkali metal is selected from the class consisting of potassium, rubidium and cesium.