Glass-metal feedthrough
A glass-metal feedthrough includes: an external conductor including steel, having a coefficient of expansion α external , and having an opening formed therein; an internal conductor disposed in the opening, the internal conductor including steel and having a coefficient of expansion α internal . The external conductor and the internal conductor are configured to not release nickel when in contact with a human or animal body or biological cells of a cell culture. A glass material surrounds the internal conductor within the opening and has a coefficient of expansion α glass . The coefficient of expansion α external of the external conductor and the coefficient of expansion α internal of the internal conductor both are greater than the coefficient of expansion α glass of the glass material.
1. A glass-metal feedthrough, comprising:
an external conductor comprising steel, having a coefficient of expansion α external , and having an opening formed therein;
an internal conductor disposed in the opening,
the internal conductor comprising steel and having a coefficient of expansion α internal ,
the external conductor and the internal conductor being configured to not release nickel when in contact with a human or animal body or biological cells of a cell culture; and
a glass material surrounding the internal conductor within the opening and having a coefficient of expansion α glass ,
the coefficient of expansion α external of the external conductor and the coefficient of expansion α internal of the internal conductor both being greater than the coefficient of expansion α glass of the glass material,
wherein the coefficient of expansion of the internal conductor α internal is 1.7 times to 4 times greater than the coefficient of expansion of the glass material α glass ,
wherein the coefficient of expansion of the internal conductor α internal and the coefficient of expansion of the external conductor α external are such that a joint pressure of at least 30 MPa is generated on a portion of the internal conductor in contact with the glass material in a temperature range of 20° C. to a glass transformation temperature of the glass material,
wherein a difference between the coefficient of expansion of the external conductor α external and the coefficient of expansion of the glass material α glass is at least 2 ppm/K in the temperature range of 20° C. to the glass transformation temperature of the glass material,
wherein the external conductor and the internal conductor both comprise AISI 316L steel.
2. The glass-metal feedthrough of claim 1 , wherein the coefficient of expansion of the external conductor α external is 1.1 times to 4 times greater than the coefficient of expansion of the glass material α glass .
3. The glass-metal feedthrough of claim 1 , wherein the glass material seals the internal conductor in the opening of the external conductor.
4. A glass-metal feedthrough, comprising:
an external conductor having a coefficient of expansion α external , and having an opening formed therein;
an internal conductor disposed in the opening,
the internal conductor comprising AISI 316L steel and having a coefficient of expansion α internal ,
the external conductor and the internal conductor being configured to not release nickel when in contact with a human or animal body or biological cells of a cell culture; and
a glass material surrounding the internal conductor within the opening and having a coefficient of expansion α glass ,
the coefficient of expansion α external of the external conductor and the coefficient of expansion α internal of the internal conductor both being greater than the coefficient of expansion α glass of the glass material,
wherein the coefficient of expansion of the internal conductor α internal is 1.7 times to 4 times greater than the coefficient of expansion of the glass material α glass ,
wherein the coefficient of expansion of the internal conductor α internal and the coefficient of expansion of the external conductor α external are such that a joint pressure of at least 30 MPa is generated on a portion of the internal conductor in contact with the glass material in a temperature range of 20° C. to a glass transformation temperature of the glass material,
wherein a difference between the coefficient of expansion of the external conductor α external and the coefficient of expansion of the glass material α glass is at least 2 ppm/K in the temperature range of 20° C. to the glass transformation temperature of the glass material,
wherein the external conductor and the internal conductor both consist of AISI 316L steel.
5. The glass-metal feedthrough of claim 4 , wherein the coefficient of expansion of the external conductor α external is 1.1 times to 4 times greater than the coefficient of expansion of the glass material α glass .
6. The glass-metal feedthrough of claim 4 , wherein the glass material seals the internal conductor in the opening of the external conductor.
7. An element for insertion into or attachment to a human or animal body or biological cells of a cell culture, the element comprising:
a glass-metal feedthrough comprising:
an external conductor comprising steel, having a coefficient of expansion α external , and having an opening formed therein;
an internal conductor disposed in the opening,
the internal conductor comprising AISI 316L steel and having a coefficient of expansion α internal ,
the external conductor and the internal conductor being configured to not release nickel when in contact with the human or animal body or the biological cells of the cell culture; and
a glass material surrounding the internal conductor within the opening and having a coefficient of expansion α glass ,
the coefficient of expansion α external of the external conductor and the coefficient of expansion α internal of the internal conductor both being greater than the coefficient of expansion α glass of the glass material,
wherein the coefficient of expansion of the internal conductor α internal is 1.7 times to 4 times greater than the coefficient of expansion of the glass material α glass ,
wherein the coefficient of expansion of the internal conductor α internal and the coefficient of expansion of the external conductor α external are such that a joint pressure of at least 30 MPa is generated on a portion of the internal conductor in contact with the glass material in a temperature range of 20° C. to a glass transformation temperature of the glass material,
wherein a difference between the coefficient of expansion of the external conductor α external and the coefficient of expansion of the glass material α glass is at least 2 ppm/K in the temperature range of 20° C. to the glass transformation temperature of the glass material,
wherein the external conductor and the internal conductor both comprise AISI 316L steel.
8. The element of claim 7 , wherein at least one of the external conductor or the internal conductor consists of AISI 316L steel.
9. The element of claim 7 , wherein the coefficient of expansion of the external conductor α external is 1.1 times to 4 times greater than the coefficient of expansion of the glass material α glass .