Polycrystalline insulating material seals between spaced members such as a terminal pin and a ferrule

• US 4,421,947 A
• Filed: 01/28/1981
• Issued: 12/20/1983
• Est. Priority Date: 10/11/1977
• Status: Expired due to Term

• Current Assignee: Pacific Coast Technologies, Inc. (Qnnect LLC)
• Original Assignee: James C. Kyle
• Inventors: Kyle, James C.
• Primary Examiner(s): Askin, Laramie E.
• Application Number:
  US06/229,151
• Time in Patent Office: 1,056 Days
• Field of Search: 174/50.58, 174/50.61, 174/50.63, 174/151, 174/152 GM, 65/33, 65/36, 65/42, 65/59.1, 65/59.3, 65/59.31, 65/59.34, 65/59.35, 65/59.4, 65/59.5, 65/59.6, 128/419 P, 228/122, 228/903, 403/28, 403/29, 403/30, 403/179, 428/432, 428/433, 428/434
• US Class Current: 174/152.0GM
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01B 17/305 by embedding in glass or ceramic material
• CPC Class Codes: Y10T 403/217 Members having different coefficients of expansion

Abstract

A material hermetically seals two members. One member may be titanium or a titanium alloy and the other member may be a noble metal such as platinum. The seal is resistant to acids and alkalis and is substantially impervious to shocks resulting from mechanical forces or abrupt changes in temperature. The material includes a pair of fluxes having different melting temperatures and a stuffing material including the oxides of zinc and zirconium. The oxides of zinc and zirconium become crystallized at the surface between one of the members and the material. An oxygen valence bond is also produced between the material and such member. The material is more amorphous at the boundary with the second member than at positions removed from such member. The material is formed by progressive heatings for at least a pair of periods of time insufficient to crystallize all of the material and by rapid coolings of the material after each of such heatings.

Claims

1. In combination,

a first member made from a noble metal,

a second member made from a material selected from the group consisting of titanium and an alloy of titanium and disposed in spaced relationship to the first member and having at least one of alpha (α

) and beta (β

) phases, and

an electrically insulating material preformed to provide partially amorphous and partially crystalline characteristics and hermetically sealing the first and second members and including at least one flux formed from the oxides of lead, silicon and boron, the insulating material being sealed to the first and second members, in at least one of the alpha (α

) and beta (β

) phases of the second member, by the application of heat to the first and second members and to the insulating material at a particular temperature for a limited period of time, the insulating material having partially amorphous and partially crystalline characteristics in the sealed relationship with the first and second members.

2. The combination set forth in claim 1 wherein

the insulating material is particularly crystalline at the boundary with the second member and wherein the insulating material has a coefficient of thermal expansion slightly greater than the coefficient of thermal expansion of the second member.

3. The combination set forth in claim 2 wherein the insulating material has properties of being self-correcting in providing a hermetic seal between the first member and the second member upon an additional application of heat at temperatures less than about 1300°

F. when a hermetic seal between the insulating material and each of the first and second members does no exist.

4. The combination set forth in claim 2 wherein

the insulating material is formed at temperatures less than about 1300°

F. and wherein the insulating material is resistant to acids and alkalies and has an electrical resistance as high as 10¹⁸ ohms.

5. The combination set forth in claim 4 wherein

the insulating material includes oxides of at least zinc and zirconium.

6. The combination set forth in claim 5 wherein

the insulating material includes the oxide of antimony.

7. The combination set forth in claim 5 wherein

the crystals in the insulating material are provided with different sizes and shapes in an intermixed relationship to enhance the flexibility of the insulating material and facilitate resistance to temperature and mechanical shocks.

8. The combination set forth in claim 7 wherein

the oxides of zinc and zirconium are in a stuffing having a range by weight of approximately 20% to 45% in the insulating material and the oxides of zinc and zirconium are included in the insulating material respectively in the form of zinc zirconium silicate, zirconium spinel and zirconium silicate.

9. The combination set forth in claim 1 wherein

the insulating material is also chemically bound by oxygen valences to the second member and the layer of the insulating material adjacent the second member is provided with crystals of different sizes and shapes to provide a flexibility for withstanding thermal and mechanical shock and wherein the first and second members and the insulating material are heated to a temperature less than 1300°

F. for the limited period of time and are then cooled in air after being heated to the temperature less than 1300°

F. for the limited period of time.

10. The combination set forth in claim 9 wherein

the insulating material has a slightly greater coefficient of thermal expansion than the second member.

11. The combination set forth in claim 9 wherein

the insulating material has the properties of providing a hermetic seal to the first and second members upon the application of additional heat to the combination of the first and second members and the insulating material when a hermetic seal has not been previously produced between the first and second members and the insulating material.

12. The combination set forth in claim 1 wherein

the insulating material includes crystals of Willemite and crystals formed by the compounds of zirconium, silicon and oxygen and the crystals of Willemite have different sizes and shapes than the crystals formed by compounds of zirconium, silicon and oxygen and the crystals of Willemite and the crystals formed by the compounds of zirconium, silicon and oxygen are concentrated at the boundary with the second member.

13. In combination,

a first member,

a second member spaced from the first member, and

electrically insulating material hermetically sealing the first and second members and including the following in its original composition:

a first flux consisting of lead oxide, boric oxide and silicon dioxide and having a first melting temperature, and

a second flux consisting of lead oxide and boric oxide and having a higher melting temperature than the first flux,

a polycrystalline stuffing including oxides of zirconium and zinc and silicon and having properties of providing in a random distribution first crystals having a first size and shape and second crystals having a second size and shape different from the first size and shape, the first and second crystals being primarily disposed in a layer adjacent to at least a particular one of the first and second members to provide a flexibility resisting thermal and mechanical shock, the first and second members and the first and second fluxes and the polycrystalline stuffing being hermetically sealed by the application of heat at a temperature less than 1300°

F. for a limited period of time and by subsequent cooling in air.

14. The combination set forth in claim 13 wherein

the polycrystalline stuffing includes zinc oxide in the form of compounds with silicon dioxide and wherein the insulating material has properties of providing Willemite in the layer adjacent at least the particular one of the first and second members and wherein the first and second members, the first and second fluxes and the polycrystalline stuffing are heated to the temperature less than 1300°

F. for a limited period less than one half (1/2) hour.

15. The combination set forth in claim 14 wherein

the insulating material is more amorphous at positions removed from the particular one of the first and second members than at the boundary of the particular one of the first and second members and wherein the material has self-correcting properties of producing a hermetic seal with the first and second members, upon a previous failure to produce a seal with the first and second members, by reheating the first and second members and the insulating material to a temperature less than 1300°

F. for a limited period of time.

16. The combination set forth in claim 15 wherein

the insulating material is formed at temperatures below about 1300°

F. and the first member is made from a noble metal and the second member is made from a material selected from the group consisting of titanium and a titanium alloy and the insulating material is provided with a coefficient of thermal expansion slightly greater than that of the second member.

17. The combination set forth in claim 13 wherein

the insulating material is formed at temperatures below about 1300°

F.

18. The combination set forth in claim 17 wherein

the first member is made from a noble metal and the second member is made from a material selected from the group consisting of titanium and a titanium alloy.

19. The combination set forth in claim 18 wherein

the second flux has a greater percentage by weight in the insulating material than the first flux and the polycrystalline stuffing has a higher melting temperature than the melting temperatures of the first and second fluxes.

20. In combination,

a first member,

a second member, and

an electrically insulating material preformed to provide partially polycrystalline and partially amorphous properties and hermetically sealing the first and second members and having a polycrystalline layer at a position adjacent the second member and an oxygen valence bond to the second member and being more amorphous at positions removed from the second member than at the boundary of the second member, the insulating material being hermetically sealed to the first and second members by heating the first and second members and the insulating material at temperatures less than about 1300°

F. for a limited period of time and by cooling the first and second members and the insulating material in air.

21. The combination set forth in claim 20 wherein

the polycrystalline layer adjacent the second member includes Willemite crystals and crystals constituting compounds of zirconium.

22. The combination set forth in claim 21 wherein

the insulating material has self-correcting properties, upon a failure to provide a hermetic seal with the first and second members, by reheating the first and second members and the insulating material to a temperature less than 1300°

F. for a limited period of time and by subsequently recooling the first and second members and the insulating material in air.

23. The combination set forth in claim 20 wherein

the surface of the first member is etched and the insulating material is retained within the etchings in the surface of the first member and wherein the limited period for the heating of the first and second members and the insulating material to a temperature less than 1300°

F. is less than one half (1/2) hour.

24. In combination,

a first member made from a noble metal,

a second member displaced outwardly from the first member and made from a material selected from the group consisting of titanium and a titanium alloy, and

an insulating material preformed to provide partially amorphous and partially polycrystalline characteristics and directly engaging the first and second members and hermetically sealing the first and second members by the application of heat at a particular temperature for a limited period of time and having a partially amorphous and partially crystalline composition in the hermetically sealed relationship with the first and second members and having a primarily polycrystalline composition at the boundary with the second member.

25. The combination set forth in claim 24 wherein

an oxygen valence bond exists between the insulating material and the second member.

26. The combination set forth in claim 24 wherein

the surface of the first member is etched and the insulating material is bound in the etched surface of the first member and the insulating material has a slightly greater coefficient of expansion than the second member.

27. The combination set forth in claim 26 wherein

the polycrystalline composition at the boundary between the second member and the insulating material is produced by a mixture of oxides of zinc and zirconium.

28. The combination set forth in claim 24 wherein

the insulating material has self-correcting properties of providing a hermetic seal to the first and second members upon the application of additional heat, at a temperature less than 1300°

F. for a limited period of time, to the combination of the first and second members and the insulating material when a hermetic seal has not been previously produced.

29. The combination set forth in claim 24 wherein

the surface of the first member is etched and the insulating material is bound in the etched surface of the first member and wherein the first and second members and the insulating material are heated to a temperature less than 1300°

F. for the limited period of time and are then cooled in air to obtain a hermetically sealed relationship between the insulating material and the first and second members.

30. The combination set forth in claim 24 wherein

the insulating material has a slightly greater coefficient of expansion than the second member and wherein the particular temperature is less than 1300°

F. and wherein the limited period of time for the application of heat at the temperature less than 1300°

F. is less than one half (1/2) hour.

31. The combination set forth in claim 24 wherein

the polycrystalline composition at the boundary between the second member and the insulating material is produced by a mixture of oxides of zinc and zirconium.

32. In combination,

a first member,

a second member separated from the first member, and

an electrically insulating material preformed to provide partially amorphous and partially polycrystalline properties and hermetically sealing the first and second members and having self-correcting properties of providing a hermetic seal between the first and second members by the application of heat to the combination of the first and second members and the insulating material at temperatures less than about 1300°

F. for a limited period of time when a hermetic seal does not exist, the insulating material being partially amorphous and partially crystalline in the hermetically sealed relationship with the first and second members and being more crystalline at the boundary between the second member and the insulating material than at positions removed from such boundary.

33. The combination set forth in claim 32 wherein

the insulating material is primarily polycrystalline at the boundary between the second member and the insulating material and the polycrystals have a random orientation of different sizes and shapes to provide a flexibility in withstanding thermal and mechanical shocks and wherein the first and second members and the insulating material are cooled in air after being heated to the temperature less than 1300°

F. for the limited period of time.

34. The combination set forth in claim 33 wherein

the polycrystals at the boundary between the second member and the insulating material comprise a mixture of oxides of zinc and zirconium and wherein the limited period for heating the first and second members and the insulating material to the temperature less than 1300°

F. is less than one half (1/2) hour.

35. The combination set forth in claim 33 wherein

the surface of the first member is etched and the insulating material is locked in the etched surface of the first member and the insulating material includes the oxides of silicon, boron and lead.

36. The combination set forth in claim 35 wherein

the insulating material has a slightly greater coefficient of thermal expansion than the second member and the insulating material includes a first flux having a relative percentage by weight of approximately 15% to 25% by weight and a second flux having a relative percentage of approximately 40% to 55% by weight and a crystal stuffing material providing the remaining percentage by weight and wherein

the first flux has the following composition by weight:

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Lead Oxide 68.5 Boric Oxide 10.5 Silicon Dioxide 21.0 ______________________________________

and the second flux has the following composition by weight;

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Lead Oxide 80.0 Boric Oxide 20.0 ______________________________________

37. The combination set forth in claim 36 wherein

the crystal stuffing material has the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Cobalt Oxide 31.3 Quartz 25.6 Zirconium Spinel 14.2 Zinc Zirconium Silicate 14.2 Tin Oxide 14.2 ______________________________________

38. The combination set forth in claim 36 wherein

the crystal stuffing material has the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Silicon Dioxide 20 Molybdic Oxide 4 Cobalt Oxide 3 Lead Antimonate 15 Zinc Oxide 8 Zirconium Silicate 30 Magnesium Zirconium Silicate 20 ______________________________________

39. The combination set forth in claim 36 wherein the crystal stuffing material includes lead antimonate, zinc zirconium silicate, zirconium spinel and zirconium silicate.

40. The combination set forth in claim 36 wherein

the crystal stuffing material has the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Lead Antimonate 2 Zinc Zirconium Silicate 1 Zirconium Spinel 1 Zirconium Silicate 1 ______________________________________

41. The combination set forth in claim 40 wherein

the first member is made from a noble metal and the second member is made from a material selected from the group consisting of titanium and a titanium alloy.

42. The combination set forth in claim 35 wherein

the first member is made from a noble metal and the second member is made from titanium in at least one of the alpha (α

) and beta (β

) phases.

43. The combination set forth in claim 32 wherein

the first member is made from a noble metal and the second member is made from a material selected from the group consisting of titanium and an alloy of titanium.

44. In combination in a heart pacemaker,

a terminal pin made from a noble metal,

a ferrule made from a material selected from the group consisting of titanium and an alloy of titanium, and

a material hermetically sealing the terminal pin and the ferrule and having insulating properties,

the insulating material being partially amorphous and partially crystalline and being particularly crystalline at the boundary with the ferrule,

oxides of lead, boron and silicon being included in the insulating material in a first flux and oxides of lead and boron being included in the insulating material in a second flux having a higher melting temperature than the first flux and oxides of lead, zinc, antimony and zirconium being included in the insulating material in a crystalline stuffing and the first flux being included in the insulating material with a weight of approximately 15% to 25% and the second flux being included in the insulating material with a weight of approximately 40% to 55% and the crystalline stuffing constituting the remainder of the insulating material.

45. In combination,

a first member,

a second member spaced from the first member, and

an insulating material disposed between the first and second members and hermetically sealing the first and second members and formed from:

(a) a first flux consisting of lead oxide, silicon dioxide and boric ocide and having a first melting temperature,

(b) a second flux consisting of lead oxide and boric oxide and having a higher melting temperature than the first flux, and

(c) a crystalline stuffing including oxides of zirconium and zinc and silicon and having properties of providing crystals in a layer adjacent to at least a particular one of the first and second members,

the insulating material being formed at temperatures below about 1300°

F. and the first member being made form a noble metal and the second member being made from a material selected from the group consisting of titanium and a titanium alloy and the insulating material being provided with a coefficient of thermal expansion slightly greater than that of the second member.

46. The combination set forth in claim 45 wherein

the first flux is formed from the following materials:

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Lead Oxide 68.5 Boric Oxide 10.5 Silicon Dioxide 21.0 ______________________________________

and the second flux is formed from the following materials;

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Lead Oxide 80.0 Boric Oxide 20.0 ______________________________________

47. In combination,

a first member,

a second member separated from the first member, and

insulating material hermetically sealing the first and second members and having self-correcting properties of providing a hermetic seal between the first and second members by the application of heat to the combination of the first and second members and the insulating material when a hermetic seal does not exist,

the insulating material being primarily polycrystalline at the boundary between the second member and the insulating material and the polycrystals having a random orientation of different sizes and shapes to provide a flexibility in withstanding thermal and mechanical shocks and the insulating material being progressively amorphous from the boundary between the second member and the insulating material,

the surface of the first member being etched and the insulating material being locked in the etched surface of the first member,

the insulating material including first and second fluxes each including boric oxide, the first and second fluxes forming eutectics to effectively decrease the melting temperature of the boric oxide in the fluxes.

48. In combination,

a first member,

a second member disposed in spaced relationship to the first member, and

an electrically insulating material preformed to a partially amorphous and partially polycrystalline structure with the amorphous and polycrystalline structure being intermixed, the insulating material being disposed between the first and second members and the first and second members and the insulating material being heated at a temperature below 1300°

F. for a limited period of time to hermetically seal the first and second members and the insulating material.

49. The combination set forth in claim 48 wherein

the first member is made from a noble metal and the second member is made from a material selected from the group consisting of titanium and a titanium alloy and the first and second members and the insulating material are cooled in air after being heated to the temperature less than 1300°

F. for the limited period of time.

50. The combination set forth in claim 49 wherein

the material is more crystalline at the boundary between the second member and the insulating material than at positions removed from such boundary after being heated with the first and second members to the temperature less than 1300°

F. for the limited period of time and the insulating material is directly sealed to the first and second members.

51. The combination set forth in claim 50 wherein

the surface of the first member is etched by the heating of the first and second members and the insulating material to the temperature less than 1300°

F. for the limited period of time and the insulating material is locked in the etched surface of the first member by such heating.

52. The combination set forth in claim 50 wherein

the insulating material is formed from the oxides of silicon, boron, lead, zinc and zirconium and the limited period of time for the heating of the first and second members and the insulating material to the temperarture less than 1300°

F. is less than one half (1/2) hour.

53. The combination set forth in claim 48 wherein the insulating material includes,

a first flux having the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Lead Oxide 68.5 Boric Oxide 10.5 Silicon Dioxide 21.0 ______________________________________

and a second flux having the following composition;

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Lead Oxide 80.0 Boric Oxide 20.0 ______________________________________

and a crystal stuffing including the oxides of zinc, zirconium and silicon,

the first flux being included in the insulating material in the range of approximately 15% to 25% by weight and the second flux being included in the insulating material in the range of approximately 40% to 55% by weight and the remainder of the insulating material being constitued by the crystal stuffing.

54. The combination set forth in claim 53 wherein

the crystal stuffing has the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative % By Weight ______________________________________ Lead Antimonate 2 Zinc Zirconium Silicate 1 Zirconium Spinel 1 Zirconium Silicate 1 ______________________________________

55. The combination set forth in claim 53 wherein the crystal stuffing has the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative Parts By Weight ______________________________________ Silicon Dioxide 33.3 Zinc Oxide 33.3 Cobalt Oxide 10.0 Zirconium Silicate 15.0 Molybdic Oxide 5.0 ______________________________________

56. The combination set forth in claim 48 wherein

the insulating material includes at least one flux having at least one of the following compositions:

space="preserve" listing-type="tabular">______________________________________ Relative Parts By Weight Flux Flux Flux Flux Flux C D E F G ______________________________________ Compound Lead oxide (PbO) 81.8 78.8 66.6 55.5 48.6 Boron Oxide (B.sub.2 O.sub.3) 10.6 9.6 18.6 3.0 6.9 Silicon dioxide (SiO.sub.2) 7.6 11.6 14.8 29.6 25.0 Sodium oxide (Na.sub.2 O) 4.4 3.6 Titanium dioxide (TiO.sub.2) 4.0 2.4 Lithium oxide (Li.sub.2 O) 3.6 Zirconium dioxide (ZrO.sub.2) 6.7 Characteristics Melting Point (°

F.) 850 950 1050 1140 1120 12 Coefficient of 104 85 76 90 85 (in/in ×

10.sup.-7) ______________________________________

57. The combination set forth in claim 56 wherein the insulating material includes a crystal stuffing having the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative Parts By Weight ______________________________________ Lead Antimonate 2 Zinc Zirconium Silicate 1 Zirconium Spinel 1 Zirconium Silicate 1 ______________________________________

58. The combination set forth in claim 56 wherein the insulating material includes a crystal stuffing having the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative Parts By Weight ______________________________________ Silicon Dioxide 33.3 Zinc Oxide 33.3 Cobalt Oxide 10.0 Zirconium Silicate 15.0 Molybdic Oxide 5.0 ______________________________________

59. The combination set forth in claim 56 wherein the insulating material includes a crystal stuffing having the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative Parts By Weight ______________________________________ Cobalt Oxide 31.3 Quartz 25.6 Zirconium Spinel 14.2 Zinc Zirconium Silicate 14.2 Tin Oxide 14.2 ______________________________________

60. The combination set forth in claim 56 wherein the insulating material includes a crystal stuffing having the following composition:

space="preserve" listing-type="tabular">______________________________________ Material Relative Parts By Weight ______________________________________ Silicon Dioxide 20 Molybdic Oxide 4 Cobalt Oxide 3 Lead Antimonate 15 Zinc Oxide 8 Zirconium Silicate 30 Magnesium Zirconium Silicate 20 ______________________________________

61. The combination set forth in claim 48 wherein

the insulating material includes the oxides of silicon, boron and lead and the limited period of time for the heating of the first and second members and the insulating material to the temperature less than 1300°

F. is less than one half (1/2) hour.