Method of conforming clear vitreous gal of silica-titania material

• US 4,278,632 A
• Filed: 02/08/1980
• Issued: 07/14/1981
• Est. Priority Date: 02/08/1980
• Status: Expired due to Term

• Current Assignee: Philips Electronicsnorth America Corporation (Koninklijke Philips N.V.)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Yoldas, Bulent E.
• Primary Examiner(s): McCarthy, Helen M.
• Application Number:
  US06/119,689
• Time in Patent Office: 522 Days
• Field of Search: 65/DIG. 14, 65/17, 106/52, 264/66, 264/61
• US Class Current: 264/621
• CPC Class Codes: C03B 19/1065 by liquid phase reactions, e.g. by means of a gel phase
• CPC Class Codes: C03B 19/12 by liquid-phase reaction processes
• CPC Class Codes: C03B 2201/42 doped with titanium
• CPC Class Codes: C03B 37/016 by a liquid phase reaction process, e.g. through a gel phase
• CPC Class Codes: C03C 1/008 for the production of films or coatings
• CPC Class Codes: C03C 12/00 Powdered glass C03C8/02 takes precedence; Bead compositions
• CPC Class Codes: C03C 17/02 with glass C03C17/34, C03C17/44 take precedence
• CPC Class Codes: C03C 3/00 Glass compositions
• CPC Class Codes: C03C 3/076 with 40% to 90% silica, by weight C03C3/045 takes precedence
• CPC Class Codes: Y10S 65/901 Liquid phase reaction process

Abstract

Method for forming clear vitreous material substantially comprising silica-titania binary which contains up to about 40 mole percent titania without melting the constituents used in forming the material. There is separately prepared a clear organic-solvent-solution of partially hydrolyzed alkoxide of one of the binary members. To this prepared solution is added the other binary member either in the form of alkoxide or a clear organic-solvent solution of partially hydrolyzed alkoxide of the other member. The mixed solutions are reacted and additional water is added as required to complete the hydrolysis of the alkoxide. The resulting product is dried and then heated at a relatively low temperature to evolve residual organic components. The binary vitreous material can be processed into monolithic silica-titania glass bodies, or silica-titania coatings for substrates, or into silica-titania vitreous powder which can be sintered into glass bodies or which can be melted at a lower temperature than normally required to form silica-titania glass.

Claims

1. The method of forming a monolithic clear vitreous member substantially comprising silica-titania binary which contains up to about 40 mole percent titania without melting the constituents used in forming the monolithic clear vitreous member, which method comprises:

(a) preparing as a precursor of one of said binary constituents a predetermined amount of clear solution of partially hydrolyzed alkoxide which prior to hydrolyzation is represented by the formula M(OR)₄ where M is one of silicon and titanium, R is alkyl with from 1 to 6 carbon atoms, the solution solvent comprises organic solvent for any metallic or metalloid alkoxide precursor and any partially hydrolyzed metallic or metalloid alkoxide precursor used in forming said silica-titania vitreous member, in the case M is silicon hydrolyzing water is present in amount of from about 1 mole to about 4 moles per mole of silicon alkoxide prior to hydrolyzation, and in the case M is titanium hydrolyzing water is present in amount of from about 1 mole to about 3 moles per mole of titanium alkoxide prior to hydrolyzation;

(b) adding to and reacting with said prepared solution a predetermined amount of precursor of the other of said binary constituents in the form of (1) a partially hydrolyzed clear solution of said other binary constituents which prior to hydrolyzation is represented by the formula M'"'"'(OR)₄ where M'"'"' is said other of silicon and titanium, R is alkyl with from 1 to 6 carbon atoms, the solution solvent comprises organic solvent for any metallic or metalloid alkoxide precursor and any partially hydrolyzed metallic or metalloid alkoxide precursor used in forming said silica-titania vitreous member, in the case M'"'"' is silicon hydrolyzing water is present in amount of from about 1 mole to about 4 moles per mole of silicon alkoxide prior to hydrolyzation, and in the case M'"'"' is titanium hydrolyzing water is present in amount of from about 1 mole to about 3 moles per mole of titanium alkoxide prior to hydrolyzation;

or (2) alkoxide of said other binary constituents which is represented by the formula M'"'"'(OR)₄ where M'"'"' is said other of silicon and titanium and R is alkyl with from 1 to 6 carbon atoms; and

including with at least one of said precursors a small amount of suitable mineral acid, and said predetermined amounts of said one binary precursor relative to said other binary precursor being such that the atom ratio of total combined titanium to total combined silicon is that molar ratio of titania to silica which is desired in the formed monolithic clear vitreous member;

(c) adding to the resulting reacted solution any additional water as required to complete the hydrolysis reaction of said titanium alkoxide and said silicon alkoxide, and allowing to stand until said reacted precursors form into a gel which is a clear, stiff, single phase containing a chemically formed glass network;

(d) conforming the gel into a member having a predetermined configuration, slowly drying the conformed member, and heating the resulting conformed and dried member at a temperature in the range of from about 400°

C. to about 600°

C. to evolve any residual organic components to produce a clear member; and

(e) sintering the resulting conformed clear member at a temperature below its melting temperature to form said monolithic clear vitreous member.

2. The method as specified in claim 1, wherein M is silicon and M'"'"' is titanium.

3. The method as specified in claim 2, wherein M(OR)₄ is Si(OC₂ H₅)₄, the solution solvent is ethanol, and M'"'"'(OR)₄ is Ti(OC₂ H₅)₄.

4. The method as specified in claim 1, wherein M is titanium and M'"'"' is silicon.

5. The method as specified in claim 4, wherein M(OR)₄ is Ti(OC₂ H₅)₄, the solution solvent is ethanol to which said hydrolyzing water is added along with a small amount of mineral acid, and M'"'"'(OR)₄ is Si(OC₂ H₅)₄ which has the predetermined configuration into which the gel is initially formed.