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Chemically durable nitrogen containing phosphate glasses useful for sealing to metals
| Details |
Inventors: Day, Delbert E.; Wilder, Jr., James A.;
Assignee: The United States of America as represented by the United States (Washington, DC)
Primary Examiner: McCarthy; Helen M.
Assistant Examiner:
Attorney, Agent or Firm: McMillan; Armand, Sopp; Albert, Esposito; Michael F.
The chemical durability of alkali phosphate glasses is improved by incorporation of up to 23 weight percent of nitrogen. A typical phosphate glass contains: 10 to 60 mole % of Li.sub.2 O, Na.sub.2 O or K.sub.2 O; 5-40 mole % of BaO or CAO; 0-1 to 10 mole % of Al.sub.2 O.sub.3 ; and 40-70 mole % of P.sub.2 O.sub.5. Nitrides, such as AlN, are the favored additives. |
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DETAILED DESCRIPTION What is claimed is: 1.
An alkali phosphate glass comprising 10-60 mole percent Li.
sub.
2 O, Na.
sub.
2 O or K.
sub.
2 O, 5-40 mole percent BaO or CaO, 0.
1-10 mole percent Al.
sub.
2 O.
sub.
3, and 40-70 mole percent P.
sub.
2 O.
sub.
5, and being of enhanced chemical durability due to said glass further comprising about 0.
15 to 23 wt percent of nitrogen added in the form of a metal nitride.
2.
The phosphate glass of claim 1 comprising up to 0.
1 mole percent Pt; up to 10 mole percent TiO.
sub.
2 ZrO.
sub.
2, Y.
sub.
2 O.
sub.
2, La.
sub.
2 O.
sub.
3 or Ta.
sub.
2 O.
sub.
5 ; up to five mole percent CoO, CuO, SnO, Ag.
sub.
2 O, Cr.
sub.
2 O.
sub.
3 or NiO; or up to ten mole percent PbO, WO.
sub.
3, B.
sub.
2 O.
sub.
3, SiO.
sub.
2, GeO.
sub.
2 or ZnO.
3.
A phosphate glass of claim 1 comprising about 0.
15 to 2.
0 wt.
% of nitrogen.
4.
A phosphate glass of claim 3 comprising about 0.
17 to 0.
7 wt.
% of nitrogen.
5.
A phosphate glass of claim 1 wherein the nitrogen is added in the form of AlN.
6.
A phosphate glass of claim 3 wherein the nitrogen is added in the form of AlN.
7.
A phosphate glass of claim 4 wherein the nitrogen is added in the form of AlN.
8.
A phosphate glass of claim 1 wherein the nitrogen is added in the form of Si.
sub.
3 N.
sub.
4, YN, LaN or BN.
9.
A phosphate glass of claim 1 wherein the nitrogen is added in the form of Ca.
sub.
3 N.
sub.
2 or Li.
sub.
3 N.
10.
A method of improving the chemical durability of an alkali phosphate glass comprising 10-60 mole percent Li.
sub.
2 O, Na.
sub.
2 O or K.
sub.
2 O, 5-40 mole percent BaO or CaO, 0.
1-10 mole percent Al.
sub.
2 O.
sub.
3, and 40-70 mole percent P.
sub.
2 O.
sub.
5, by incorporating therein 0.
15 to 23 wt percent nitrogen in the form of a metal nitride added to the molten glass.
11.
In a glass to metal seal, the improvement wherein the glass is a phosphate glass of claim 1.
Description:
BACKGROUND OF THE INVENTION This invention relates to an improvement in phosphate glasses whereby they have a significantly enhanced chemical durability, i.
e.
, corrosion resistance
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Manufacturing Materials 
