Patent US4470537A successfully refreshed from Google Patents.
US4470537A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid state bonding of ceramic and metal parts
Assignee: Max-Planck-Gesellschaft zur Förderung der Wissenschaften eV
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Filing: 1982-08-04
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Granted: 1984-09-11
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Expires: 2002-08-04
Abstract
Abstract For solid state bonding, the faces of ceramic and metal parts to be bondedre placed together, acted upon by a gage pressure if desired, and are heated to a bonding temperature which is under their melting temperatures so that an inbetween or intermediate layer is formed between the two parts. For increasing the bond strength the metal used is one undergoing a phase transition on cooling down from the bonding temperature, the phase in existence at the bonding temperature having a smaller volume than the phase stable at room temperature, so that the decrease in the volume of the metal as dependent on the coefficient of thermal expansion is balanced at least to some degree by the volume change on phase transition.
Inventors
- 👤 Wolfgang Diem
- 👤 Gerhard Elssner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:14
CPC Classifications
C; C04; C04B; C04B37/00; C04B37/02; C04B37/021; B; B23; B23K; B23K20/00; B23K20/22; B23K20/233; B23K35/00; B23K35/001; B23K35/005; C04B37/003; C04B37/006; C04B2237/00; C04B2237/02; C04B2237/12; C04B2237/122; C04B2237/30; C04B2237/32; C04B2237/36; C04B2237/368; C04B2237/50; C04B2237/70; C04B2237/706; Y; Y10; Y10S; Y10S228/00; Y10S228/903
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
198 words
A solid state bonding process for producing a bond between a metal part and a ceramic part, comprising the steps of selecting as the material of said metal part a metal which has first and second crystalline phases which are respectively stable within first and second temperature ranges, wherein said first temperature range is higher than room temperature and includes a bonding temperature which is below the melting temperatures of said metal and ceramic parts, wherein said second temmperature range is lower than said bonding temperature and includes room temperature, and wherein said metal undergoes an increase in volume when cooled due to a crystalline reconfiguration during a transition from said first crystalline phase to said second crystalline phase; thereafter placing surfaces of said metal part and said ceramic part together; thereafter heating said parts to said bonding temperature, which causes a bonding layer to be produced therebetween; and thereafter cooling said metal and ceramic parts from said bonding temperature to room temperature, said increase in volume of said metal part due to said crystalline reconfiguration during said cooling offsetting in part the decrease in volume of said metal part due to the coefficient of thermal expansion thereof.
Claim 2
Dependent Claim
198 words
A solid state bonding process for producing a bond between a metal part and a ceramic part, comprising the steps of selecting as the material of said metal part a metal which has first and second crystalline phases which are respectively stable within first and second temperature ranges, wherein said first temperature range is higher than room temperature and includes a bonding temperature which is below the melting temperatures of said metal and ceramic parts, wherein said second temmperature range is lower than said bonding temperature and includes room temperature, and wherein said metal undergoes an increase in volume when cooled due to a crystalline reconfiguration during a transition from said first crystalline phase to said second crystalline phase; thereafter placing surfaces of said metal part and said ceramic part together; thereafter heating said parts to said bonding temperature, which causes a bonding layer to be produced therebetween; and thereafter cooling said metal and ceramic parts from said bonding temperature to room temperature, said increase in volume of said metal part due to said crystalline reconfiguration during said cooling offsetting in part the decrease in volume of said metal part due to the coefficient of thermal expansion thereof.
Claim 3
Dependent Claim
98 words
The process as claimed in claim 1, including the step of selecting the material of said metal part and the material of said ceramic part so that, during said step of cooling said metal and ceramic parts from said bonding temperature to room temperature, the difference between the decrease in the volume of said metal part due to its coefficient of thermal expansion and the increase in the volume of said metal part due to said crystalline reconfiguration is approximately equal to the decrease in the volume of said ceramic part due to its coefficient of thermal expansion.
Claim 4
Dependent Claim
96 words
The process as claimed in claim 1 or claim 2, wherein said step of cooling down said metal and ceramic parts produces an anisotropic stress condition therein having a greatest inner mechanical strain which acts in a direction dependent on a thickness of said metal part in the region of said bonding layer, said greatest inner mechanical strain being directed into said ceramic part when said thickness of said metal part is greater than a predetermined value; and including the step of selecting said thickness of said metal part to be greater than said predetermined value.
Claim 5
Dependent Claim
20 words
The process as claimed in claim 1 or claim 2, wherein said material selected for said metal part is zirconium.
Claim 6
Dependent Claim
21 words
The process as claimed in claim 1 or claim 2, wherein said bonding temperature is between 1150° C. and 1200° C.
Claim 7
Dependent Claim
18 words
The process as claimed in claim 1 or claim 2, wherein said ceramic material is hot-pressed silicon nitride.
Claim 8
Dependent Claim
28 words
The process as claimed in claim 1 or claim 2, wherein said metal part has a thickness greater than 0.6 mm in the region of said bonding layer.
Claim 9
Dependent Claim
31 words
The process as claimed in claim 1 or claim 2 including, during said heating and cooling steps, the step of pressing said metal and ceramic parts together with a predetermined pressure.
Claim 10
Dependent Claim
26 words
The process as claimed in claim 1 or claim 2, wherein said heating step produces said bonding layer through diffusion of said metal and ceramic parts.
Claim 11
Dependent Claim
28 words
The process as claimed in claim 1 or claim 2, wherein said heating step produces said bonding layer through a chemical reaction of said metal and ceramic parts.
Claim 12
Dependent Claim
49 words
The process as claimed in claim 1 or claim 2, wherein two said ceramic parts are provided, and wherein said placing step includes the step of placing a surface on each said ceramic part against a respective one of two surfaces provided on opposite sides of said metal part.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-11 | 1988-03-12 | 1988-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-11 | 1992-03-12 | 1992-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-11 | 1996-03-12 | 1996-09-11 | $7700.00 | Window Closed / Lapsed |