High temperature brazing of metals and ceramics to carbon substrates
An apparatus includes a first component comprising a carbon composite substrate. A high temperature coating is disposed on the surface of the carbon composite substrate. The high temperature coating includes a bond layer of a metal carbide on the surface of the substrate. The apparatus includes a second component, and braze material joining the surface of the first component to the second component. In some examples, a brake assembly may include a rotor having a surface configured to interface with another component of the brake assembly. The brake assembly includes an insert joined to the surface of the rotor without a mechanical fastener, and the insert defines a tough mechanical contact surface configured to protect the rotor.
1 . An article comprising:
a first component comprising:
a substrate comprising a carbon matrix; and
a high temperature coating on a surface of the substrate, wherein the high temperature coating comprises a bond layer of a metal carbide on the surface of the substrate formed from and integrated with the surface of the substrate, wherein the bond layer extends into and substantially fills surface voids of the carbon matrix to form a substantially continuous coating formed in situ from the substrate, and wherein the bond layer comprises a metal-rich metal carbide having a stoichiometrically greater amount of metal than carbon;
a second component comprising a carbon substrate, a carbon/carbon composite substrate, or a monolithic ceramic substrate; and
a layer of braze material joining a surface of the high temperature coating of the first component to a surface of the second component.
2 . The article of claim 1 , wherein the substrate of the first component comprises a carbon substrate, carbon/carbon composite substrate, or a monolithic ceramic substrate.
3 . The article of claim 1 , wherein the first component and the second component have a substantially similar CTE.
4 . The article of claim 1 ,
wherein the second component comprises a monolithic ceramic substrate, and
wherein the monolithic ceramic substrate comprises a rare-earth silicate.
5 . The article of claim 1 , wherein the metal carbide comprises silicon carbide.
6 . The article of claim 1 , wherein the braze material comprises a platinum group metal.
7 . The article of claim 1 , wherein the first component comprises a carbon/carbon composite, the high temperature coating comprises silicon carbide, the braze material comprises platinum, and the second component comprises ytterbium disilicate.
8 . The article of claim 1 , wherein the article is a component of a brake assembly.
9 . The article of claim 1 , wherein the second component defines a mechanical contact surface configured to protect the first component.
10 . The article of claim 1 , wherein a thickness of the bond layer is less than about 30 micrometers.
11 . The article of claim 1 , wherein a thickness of the braze material is less than about 20 millimeters.
12 . An article comprising:
a first component comprising:
a substrate comprising a carbon/carbon composite; and
a high temperature coating on a surface of the substrate, wherein the high temperature coating comprises a bond layer of silicon carbide on the surface of the substrate, and wherein a thickness of the high temperature coating is between 1 micrometer and 30 micrometers, wherein the thickness of the high temperature coating is formed by converting a surface portion of the substrate from carbon to the silicon carbide, and wherein the surface portion of the substrate has a thickness of between 1 micrometer and 30 micrometers, and wherein the bond layer extends into and substantially fills surface voids of a carbon matrix of the carbon/carbon composite to form a substantially continuous coating formed in situ from the substrate;
a second component comprising a monolithic ceramic substrate of ytterbium disilicate; and
a braze material joining a surface of the high temperature coating of the first component to a surface of the second component, the braze material defining a layer with a thickness between 0.5 millimeters and 20 millimeters, and the braze material comprises a platinum group metal.
13 . A method comprising:
forming a high temperature coating on a surface of a substrate of a first component, wherein the first component comprises a substrate comprising a carbon matrix, and wherein forming the high temperature coating comprises forming a bond layer of a metal carbide on the surface of the substrate by converting a surface portion of the substrate from carbon to the metal carbide, wherein the bond layer extends into and substantially fills surface voids of the carbon matrix to form a substantially continuous coating formed in situ from the substrate; and
joining a surface of a second component to a surface of the high temperature coating of the first component by brazing with a layer of braze material, wherein the second component comprises a carbon substrate, a carbon/carbon composite substrate, or a monolithic ceramic substrate.
14 . The method of claim 13 , wherein the substrate comprises a carbon, carbon/carbon composite, or a monolithic ceramic substrate.
15 . The method of claim 13 ,
wherein the method further comprises forming a high temperature coating on a surface of the substrate of the second component.
16 . The method of claim 13 , wherein the first component and the second component have a substantially similar CTE.
17 . The method of claim 13 , wherein the second component comprises a monolithic ceramic substrate, and the monolithic ceramic substrate comprises a rare-earth silicate or rare-earth disilicate.
18 . The method of claim 13 , wherein the metal carbide comprises silicon carbide.
19 . The method of claim 13 , wherein the braze material comprises a platinum group metal.
20 . The method of claim 13 , wherein the first component comprises a carbon/carbon composite, the high temperature coating comprises silicon carbide, the braze material comprises platinum, and the second component comprises ytterbium disilicate.