Transient liquid phase ceramic bonding
First Claim
1. A method for bonding refractory materials, comprising:
- (a) providing first and second articles, said first article including Si3 N4 ;
(b) placing at least three metal layers between said first and second articles, said first metal layer being located between said second and third metal layers, said first metal layer including a refractory metal, and said second and third metal layers each having a melting point which is lower than said refractory metal;
(c) pressing said first, second, and third metal layers between said first and second articles to form an assembly;
(d) heating said assembly to a first temperature sufficient to form a liquid from said second and third metal layers, but said first temperature being not sufficient to melt said first metal layer by itself; and
(e) maintaining said assembly at said first temperature until said liquid disappears and a solid bonding layer is formed between said first and second articles, said bonding layer having a higher melting point than said first temperature.
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Accused Products
Abstract
Ceramics are joined to themselves or to metals using a transient liquid phase method employing three layers, one of which is a refractory metal, ceramic or alloy. The refractory layer is placed between two metal layers, each of which has a lower melting point than the refractory layer. The three layers are pressed between the two articles to be bonded to form an assembly. The assembly is heated to a bonding temperature at which the refractory layer remains solid, but the two metal layers melt to form a liquid. The refractory layer reacts with the surrounding liquid and a single solid bonding layer is eventually formed. The layers may be designed to react completely with each other and form refractory intermetallic bonding layers. Impurities incorporated into the refractory metal may react with the metal layers to form refractory compounds. Another method for joining ceramic articles employs a ceramic interlayer sandwiched between two metal layers. In alternative embodiments, the metal layers may include sublayers. A method is also provided for joining two ceramic articles using a single interlayer. An alternate bonding method provides a refractory-metal oxide interlayer placed adjacent to a strong oxide former. Aluminum or aluminum alloys are joined together using metal interlayers.
95 Citations
31 Claims
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1. A method for bonding refractory materials, comprising:
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(a) providing first and second articles, said first article including Si3 N4 ; (b) placing at least three metal layers between said first and second articles, said first metal layer being located between said second and third metal layers, said first metal layer including a refractory metal, and said second and third metal layers each having a melting point which is lower than said refractory metal; (c) pressing said first, second, and third metal layers between said first and second articles to form an assembly; (d) heating said assembly to a first temperature sufficient to form a liquid from said second and third metal layers, but said first temperature being not sufficient to melt said first metal layer by itself; and (e) maintaining said assembly at said first temperature until said liquid disappears and a solid bonding layer is formed between said first and second articles, said bonding layer having a higher melting point than said first temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for bonding refractory materials, comprising:
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(a) providing first and second articles; (b) placing at least three layers between said first and second articles, a first of said three layers being composed of a ceramic material; (c) pressing said first, second, and third layers between said first and second articles to form an assembly; (d) heating said assembly to a first temperature sufficient to melt said second and third layers; and (e) maintaining said assembly at said first temperature until a solid bonding layer is formed between said first and second articles, said bonding layer having a higher melting point than said first temperature. - View Dependent Claims (23, 24)
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25. A method for bonding refractory materials, comprising:
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(a) providing first and second articles; (b) placing at least three metal layers between said first and second articles, said first metal layer being located between said second and third metal layers, said first metal layer including a refractory metal and impurities, said impurities reacting with said second metal Layer to form a compound having a melting temperature greater than said second metal layer; (c) pressing said first, second, and third metal layers between said first and second articles to form an assembly; (d) heating said assembly to a first temperature sufficient to form a liquid from said second and third metal layers, but said first temperature being not sufficient to melt said first metal layer; and (e) maintaining said assembly at said first temperature until said liquid disappears and a solid bonding layer is formed between said first and second articles, said bonding layer having a higher melting point than said first temperature. - View Dependent Claims (26, 27, 28)
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29. A method for bonding refractory materials, comprising:
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(a) providing first and second articles; (b) placing at least three layers between said first and second articles, said first layer being located between said second and third layers, said first layer including a refractory-metal oxide, said second and third layers including a metal being a strong oxide former to promote wetting, and said second and third layers having a melting point less than the melting point of said first layer; (c) pressing said first, second, and third layers between said first and second articles to form an assembly; (d) heating said assembly to a first temperature sufficient to form a liquid from said second and third layers, but said first temperature being not sufficient to melt said first layer; and (e) maintaining said assembly at said first temperature until said liquid disappears and a solid bonding layer is formed between said first and second articles, said bonding layer having a higher melting point than said first temperature. - View Dependent Claims (30, 31)
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Specification