US5161728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic-metal bonding
Assignee: Individual
•
Filing: 1990-03-27
•
Granted: 1992-11-10
•
Expires: 2010-03-27
Abstract
Abstract A method for reproducibly making a structural joint between a metal and a ceramic for practical uses above 600 DEG C. comprises uniformly metallizing the ceramic and increasing the ratio of the ceramic material strength to the dynamic and static mismatch stresses due to differential thermal expansions so that these mismatch stresses do not exceed the ceramic material strength at any point and time thereby preventing bond failures.
Inventors
- 👤 Chou H. Li
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:54
CPC Classifications
C; C23; C23C; C23C26/00; C23C26/02; B; B22; B22F; B22F1/00; B22F1/18; B23; B23K; B23K1/00; B23K1/19; B23K20/00; B23K20/16; B23K35/00; B23K35/001; C04; C04B; C04B37/00; C04B37/003; C04B37/006; C04B37/02; C04B37/023; C04B37/026; C22; C22C; C22C47/00; C22C47/08; C22C49/00; C22C49/14; C04B2237/00; C04B2237/02; C04B2237/12; C04B2237/122; C04B2237/123; C04B2237/124; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/343; C04B2237/345; C04B2237/348; C04B2237/36; C04B2237/363; C04B2237/365; C04B2237/368; C04B2237/38; C04B2237/385; C04B2237/40; C04B2237/402; C04B2237/405; C04B2237/406; C04B2237/407; C04B2237/50; C04B2237/61; C04B2237/68; C04B2237/70; C04B2237/704; C04B2237/708; C04B2237/72; C04B2237/76; C22C2204/00; H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0306; H05K3/00; H05K3/38
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
197 words
A method for making a liquid-diffusion formed, fully dense and substantially defect-free ceramic-metal joint for practical uses at temperatures over about 630° C., comprising: providing a ceramic; providing a metal; selecting a ceramic metallizing composition having a plurality of mixed powdered metallizing ingredients and, when molten, causing reactions between the ingredients and also with the ceramic to form a metallized layer thereon; preparing the composition to have gravitationally substantially nonsegregating qualities when applied onto said ceramic; coating onto a selected surface of the ceramic a layer of the metallizing composition, assembling together the metal and the coated ceramic surface; heating the assembled metal and coated ceramic surface to a temperature at which the metallizing composition melts to cause said reactions between the ingredients and with the cermaic thereby achieving ceramic metallization at the selected surface; and keeping the composition molten for a sufficiently long time to thereby form on the ceramic by liquid diffusion the metallized layer for bonding the ceramic to the metal, said metallized layer being strong, adherent, fully dense, substantially defect-free, and thermomechanically shock resistant and having a controlled interfacial region of substantial thickness whose microstructure is substantially free of voids, inclusions, and microcracks.
Claim 2
Independent Claim
197 words
A method for making a liquid-diffusion formed, fully dense and substantially defect-free ceramic-metal joint for practical uses at temperatures over about 630° C., comprising: providing a ceramic; providing a metal; selecting a ceramic metallizing composition having a plurality of mixed powdered metallizing ingredients and, when molten, causing reactions between the ingredients and also with the ceramic to form a metallized layer thereon; preparing the composition to have gravitationally substantially nonsegregating qualities when applied onto said ceramic; coating onto a selected surface of the ceramic a layer of the metallizing composition, assembling together the metal and the coated ceramic surface; heating the assembled metal and coated ceramic surface to a temperature at which the metallizing composition melts to cause said reactions between the ingredients and with the cermaic thereby achieving ceramic metallization at the selected surface; and keeping the composition molten for a sufficiently long time to thereby form on the ceramic by liquid diffusion the metallized layer for bonding the ceramic to the metal, said metallized layer being strong, adherent, fully dense, substantially defect-free, and thermomechanically shock resistant and having a controlled interfacial region of substantial thickness whose microstructure is substantially free of voids, inclusions, and microcracks.
Claim 3
Dependent Claim
27 words
A method as in claim 1 wherein said heating and keeping steps are done without any external pressure being applied onto the assembled ceramic and metal members.
Claim 4
Dependent Claim
21 words
A method as in claim 1 wherein said ceramic and metal are mismatched and have substantially different coefficients of thermal expansion.
Claim 5
Dependent Claim
22 words
A method as in claim 1 wherein said metallized layer is a single metallurgical phase having no inclusion, inhomogeneities or second phases.
Claim 6
Dependent Claim
28 words
A method as in claim 1 wherein the ceramic metallizing and bonding of the metallized ceramic to the metal is done substantially simultaneously in a single processing operation.
Claim 7
Dependent Claim
56 words
A method as in claim 1 for application with carbon reinforcing fibers in the manufacture of carbon composites, each fiber having a plurality of strands, and wherein said heating and keeping steps metallize each strand of every fiber and bond flawless, nodular metallized spots along the length of each fiber at a prespecified periodic distance apart.
Claim 8
Dependent Claim
99 words
A method as in claim 1 for metallizing a ceramic wherein said heating and keeping steps metallize the selected surface of the ceramic with a uniform metallized layer comprising an element selected from the group consisting of tungsten and molybdenum, said layer in its entirety having a substantially constant chemical composition; and said heating and keeping steps keep the assembled ceramic and metal heated for a sufficiently long time at a temperature at least 50 degrees Centigrade above a temperature at which the composition at least partially melts to thereby form the shock-resistant, liquid-formed bonded layer of graded composition.
Claim 9
Dependent Claim
43 words
A method as in claim 7 wherein said ceramic is a material selected from the group consisting of diamond and graphite and wherein said heating and keeping steps are done in an atmosphere selected to minimize the loss of carbon from the cermaic.
Claim 10
Dependent Claim
75 words
A method as in claim 7 for forming a metallized ceramic in the form of a graphite fiber and wherein said heating and keeping steps bond the fiber surface with a liquid-solidified, pinhole-free and microcrack-free layer of metals selected from the group consisting essentially of W, Mo, Cu, Ag, Au, Sn, Zn, Pb, Sb, Cd, Al, Mg, Ga, In, Th, Bi, Cr, Co, Fe, Mn, Ni, Nb, Pt, Pd, Pd, Rh, Ir, Os, and Ru.
Claim 11
Dependent Claim
76 words
A method as in claim 7 for use in forming a powder metallurgy product with powders selected from the group consisting of ceramics, boron, graphite, diamond, or glass in the range of 0.5 to 200 microns in diameter and wherein said heating and keeping steps bond metallized layers of up to 20 microns thick onto each powder, and including the additional step of compacting and sintering the thus surface-metallized powders to prespecified densities and mechanical properties.
Claim 12
Dependent Claim
42 words
A method as in claim 7 wherein said ceramic is a porous ceramic of controlled density or porosity, and wherein said heating and keeping steps bond the metallized layers onto the entire internal surface of all the pores in the porous ceramic.
Claim 13
Dependent Claim
61 words
A method as in claim 7 for use in a ceramic fiber-reinforced composite subjected to cyclic environmental heat-moisture conditions and wherein said heating and keeping steps bond all strands of the ceramic fibers periodically along their lengths with bonded nodular metallized spots at a specific distance apart to break up the moisture passageways into small compartments between the nodular metallized spots.
Claim 14
Dependent Claim
104 words
A method as in claim 12 wherein said ceramic fibers are in the form of multi-dimensional weave and including: providing the metallizing composition in a liquid or paste form; dipping the multi-dimensional ceramic fiber weave into the metallizing liquid or paste to preferentially provide the metallizing liquid or paste at the intersections of the fibers to thereby form the bonded nodular metallized spots for stopping deep water penetration; and controlling the size of the nodular metallized spots by adjusting at least one parameters of the metallizing liquid or paste composition selected from the group consisting of viscosity, solid content, and wettability of the composition.
Claim 15
Dependent Claim
57 words
A method as in claim 1 wherein said selecting step selects a ceramic metallizing composition of two metallizing ingredients; and including the additional step of providing one of the ingredients in a solution form while supplying the other ingredient in powders of a single substance suspended in said solution thereby ensuring substantially uniform and reproducible metallizing results.
Claim 16
Dependent Claim
61 words
A method as in claim 1 wherein said selecting step selects a ceramic metallizing composition of at least two metallizing ingredients; and including the additional step of integrating the at least two ingredients into a physically inseparable form so that the ingredients will provide a substantially constant chemical composition throughout the coated layer thereby ensuring substantially uniform and reproducible metallizing results.
Claim 17
Dependent Claim
25 words
A method as in claim 15 wherein said integrating step consists of alloying the at least two ingredients into a single substantially homogeneous alloy form.
Claim 18
Dependent Claim
54 words
A method as in claim 15 wherein one of said at least two ingredients is a solid powder while the other ingredient or ingredients are also solid, and said integrating step consists of coating the surface of said one ingredient powder with the other ingredient or ingredients to form physically integrated coated solid powders.
Claim 19
Dependent Claim
130 words
A method as in claim 1 wherein said selecting step comprises selecting the ceramic metallizing composition having two powdered ingredients of densities and sizes d 1 and D 1 , and d 2 and D 2 , respectively, d 1 and D 2 being respectively greater than d 2 and D 1 , both powders being suspended in a common suspension medium of density d m , and including the additional step of selecting the ratio of the powder sizes D 1 /D 2 to be at least equal to the square root of (d 1 -d m )/(d 2 -d m ) so that the final settling velocities of the two powders in said medium are nearly the same thereby improving the uniformity and reproducibility of the metallizing results.
Claim 20
Dependent Claim
128 words
A method as in claim 1 wherein said selecting step comprises selecting the ceramic metallizing composition having a plurality of powdered ingredients of densities and sizes d 1 and D 1 , d 2 and D 2 , . . . , d i and D i , . . . , respectively, all powders being suspended in a common suspension medium of density d m , and including the additional step of selecting the powder sizes D 1 , D 2 , . . . , D i , to make the D i 2 /(d i -d m ) substantially constant so that the final settling velocities of all the powders in said medium are nearly the same thereby ensuring substantially uniform and reproducible metallizing results.
Claim 21
Dependent Claim
74 words
A method as in claim 1 wherein said ceramic is to be bonded onto a holder, and wherein said coating step coats only a selected single point on the ceramic while the heating and keeping steps metallize the ceramic at the single coated point for bonding thereat to the holder sufficiently strongly and defect-freely for normal handling thereby leaving substantially the entire back surface of the ceramic unbonded and fully exposed to the ambient.
Claim 22
Dependent Claim
23 words
A method as in claim 20 wherein said ceramic is a gem stone selected from the group consisting of diamond, sapphire, and quartz.
References Cited (Backward Citations)
US3740822A
Cited
US4338380A
Cited
US4075364A
Cited
US4109031A
Cited
US4111572A
Cited
US4348131A
Cited
US4529836A
Cited
US4593851A
Cited
US4703884A
Cited
US4735866A
Cited
US4924033A
Cited
JPH0231472A
Cited
US4890783A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-11-10 | 1996-05-11 | 1996-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-10 | 2000-05-11 | 2000-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-10 | 2004-05-11 | 2004-11-10 | $7700.00 | Window Closed / Lapsed |