Glass composition for micro-D connector sealing

1. A tellurium-oxide-based glass composition for forming a glass-to-metal seal to alloys or metals, wherein the alloy or metal has a coefficient of thermal expansion higher than 16 ppm/° C., said composition consisting of, in molar percent:

60-80% of TeO 2 ;

5-35% of ZnO;

TiO 2 in an amount of at most 15%;

0-30% of K 2 O;

and unavoidable impurities,

said composition being essentially free of lead oxide, sodium oxide and vanadium oxide.

2. The glass composition as claimed in claim 1 , which comprises TiO 2 in an amount in molar percent of 1-13%.

3. The glass composition as claimed in claim 1 , which comprises K 2 O in an amount in molar percent of at most 30%.

4. The glass composition as claimed in claim 3 , which comprises K 2 O in an amount in molar percent of 1-20%.

5. The glass composition as claimed in claim 1 , which consists of, in molar percent:

64-79% of TeO 2 ;

14-31% of ZnO;

TiO 2 in an amount of at most 15%;

0-20% of K 2 O;

and unavoidable impurities.

6. The glass composition as claimed in claim 1 , wherein the coefficient of thermal expansion of the glass is in a range of 11-22 ppm/° C.

7. The glass composition as claimed in claim 1 , wherein the alloy or metal having a coefficient of thermal expansion higher than 16 ppm/° C. is chosen from the group consisting of aluminum and its alloys, stainless steel, copper and copper alloys.

8. The glass composition as claimed in claim 7 , wherein the alloy or metal having a coefficient of thermal expansion higher than 16 ppm/° C. is chosen from the group consisting of aluminum-silicon, aluminum-magnesium or aluminum-magnesium-silicon alloy.

9. The glass composition as claimed in claim 7 , wherein the alloy or metal having a coefficient of thermal expansion higher than 16 ppm/° C. is a copper-beryllium alloy.

10. The glass composition as claimed in claim 9 , wherein the copper-beryllium alloy is plated with nickel or plated with nickel and gold.

11. A glass-to-metal sealant between copper or a copper alloy, and an alloy or a metal having a coefficient of thermal expansion higher than 16 ppm/° C. made from the glass composition as claimed in claim 1 .

12. The glass-to-metal sealant as claimed in claim 11 , wherein the alloy or metal having a coefficient of thermal expansion higher than 16 ppm/° C. is other than copper or than a copper alloy and is chosen from the group consisting of aluminum and its alloys and stainless steel.

13. The glass-to-metal sealant as claimed in claim 11 , which is formed in a connector, between a contact made of copper or of copper alloy and an insert and/or shell made of an alloy or metal having a coefficient of thermal expansion higher than 16 ppm/° C.

14. A connector comprising a contact made of copper or of copper alloy, an insert and/or shell made of a metal or alloy having a coefficient of thermal expansion higher than 16 ppm/° C. and a glass-to-metal sealant between the contact and the insert and/or shell, wherein the sealant is a tellurium-oxide-based glass having the composition such as defined in claim 1 .

15. The connector as claimed in claim 14 , characterized in that the alloy or metal having a coefficient of thermal expansion higher than 16 ppm/° C. is chosen from the group consisting of aluminum and its alloys and stainless steel.

16. The connector as claimed in claim 14 , wherein the copper alloy or copper of the contact is not plated with nickel, wherein the alloy or metal having a coefficient of thermal expansion higher than 16 ppm/° C. is chosen from the group consisting of aluminum and its alloys and wherein the connector is non-magnetic with a residual magnetism <20 nT.

17. The connector as claimed in claim 14 , which is a micro-D connector.

18. The connector as claimed in claim 14 , which is hermetic with a helium leak rate lower than 3×10 −1 ° mbar·l/s, has an insulation resistance between the contacts and between each contact and the insert and/or shell >5 Gohm and an operating temperature able to reach as high as 200° C.

19. A process for forming a glass-to-metal seal between a contact made of copper or of copper alloy, and an insert and/or shell made of a metal or alloy having a coefficient of thermal expansion higher than 16 ppm/° C., comprising the following successive steps:

a) providing a contact made of copper or of copper alloy, and an insert and/or shell made of a metal or alloy having a coefficient of thermal expansion higher than 16 ppm/° C.;

b) providing a preform of tellurium-oxide-based glass having the composition as defined in claim 1 ;

c) bringing the preform into contact with the contact and with the insert and/or the shell;

d) using a suitable tool, maintaining contact between the assembly made up of the contact, preform and insert and/or shell;

e) heating the assembly made up of the contact, preform and insert and/or shell to a temperature and for a time sufficient to obtain the glass-to-metal seal;

f) collecting the assembly thus sealed.

20. The process as claimed in claim 19 , characterized in that the temperature of step e) is in a range of 350-500° C.