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EP0095433A1
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Reaction inhibited-silicon carbide fiber reinforced high temperature glass-ceramic composites and a method of manufacture of the same
Assignee: RTX Corp
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Filing: 1983-05-17
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Granted: —
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Expires: 2003-05-17
Abstract
Abstract A silicon carbide fiber reinforced glass-ceramic matrix composite is disclosed having high strength, fracture toughness, and improved oxidative stability even at highttempera- ture use, e.g., in excess of 1000°C. The composite is made up of a plurality of glass-ceramic layers, each layer reinforced with a plurality of unidirectional continuous length silicon carbide or discontinuous SiC fibers. The composite is formed by starting with the matrix material (preferably lithium aluminosilicate) in the glassy state and converting it from the glassy state to the crystalline state after densification of the composite. Ta or Nb compounds are added to the matrix composition prior to consolidation to form a reaction or diffusion barrier around the SiC fiber, resulting in composites with high temperature oxidation stability. Substitution of at least part of the Li 2 0 in the matrix with MgO results in an even higher temperature stable composite, e.g. up to about 1200°C.
Inventors
- 👤 John J. Brennan
- 👤 Kenneth Chyung
- 👤 Mark P. Taylor
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 08:50
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0018; C03C10/0027; C03C14/00; C03C14/002; C03C2214/00; C03C2214/02; C03C2214/03; C03C2214/20
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
79 words
A silicon carbide fiber reinforced glass-ceramic composite exhibiting use temperatures in excess of 1000 0 C characterized in comprising silicon carbide fibers implanted within a glass-ceramic matrix, said matrix being essentially free from TiO 2 and having a composition within the Li 2 O-Al 2 O 3 -As 2 O 3 -SiO 2 -Nb 2 O 5 and/or Ta 2 0 5 system, and said fibers having a reaction inhibiting, diffusion barrier coating of niobium carbide and/or tantalum carbide.
Claim 2
Dependent Claim
79 words
A silicon carbide fiber reinforced glass-ceramic composite exhibiting use temperatures in excess of 1000 0 C characterized in comprising silicon carbide fibers implanted within a glass-ceramic matrix, said matrix being essentially free from TiO 2 and having a composition within the Li 2 O-Al 2 O 3 -As 2 O 3 -SiO 2 -Nb 2 O 5 and/or Ta 2 0 5 system, and said fibers having a reaction inhibiting, diffusion barrier coating of niobium carbide and/or tantalum carbide.
Claim 3
Dependent Claim
39 words
The composite according to claim 1 characterized in that said glass-ceramic contains, expressed in terms of weight percent on the oxide basis, 0.5-3% As 2 O 3 and 1-10% Nb 2 0 5 and/or Ta 2 O 5 .
Claim 4
Dependent Claim
25 words
The composite according to claim 1 characterized in that said glass-ceramic consists essentially, expressed in terms of weight percent on the oxide basis, of about
Claim 5
Dependent Claim
43 words
The composite according to claim 3 characterized in exhibiting use temperatures up to 1200°C, wherein Li 2 0 is present in an amount of 2-3.5%, MgO is present in an amount of 1.5-6%, and ZrO 2 is present in an amount of 1-3%.
Claim 6
Independent Claim
154 words
A method for forming the silicon carbide fiber reinforced glass-ceramic composite exhibiting use temperatures in excess of 1000°C of the claims l-4 characterized in that is comprises the steps of: (a) melting batch for an essentially TiO 2 free glass having a composition within the Li 2 O-Al 2 O 3 -As 2 O 3 -SiO 2 -Nb 2 O 5 and/or Ta 2 0 5 system; (b) cooling said melt to a glass; (c) comminuting said glass to a fine powder; (d) implanting SiC fibers in said glass powder; (e) consolidating said fibers and powder at an elevated temperature and pressure for a time sufficient to form a composite body wherein a NbC and/or TaC reaction inhibiting, diffusion barrier coating is developed in situ on said fibers; (f) heat treating said composite body at an elevated temperature, but below the consolidation temperature, to cause said glass to devitrify to a highly crystalline glass-ceramic.
Claim 7
Dependent Claim
24 words
The method according to claim 5 characterized in that said consolidating comprises hot pressing at about 1100°C-1500°C at pressures up to about 68.95 MPa.
Claim 8
Dependent Claim
27 words
A method according to claim 5 characterized in that said heat treating comprises exposing said composite to a temperature between about 750 -1200°C for about 0.25-24 hours.
Claim 9
Dependent Claim
39 words
A glass-ceramic body exhibiting high strength and a use temperature up to 1200°C, characterized in that beta-spodumene and/or beta-quartz solid solution constitutes the predominant crystal phase, consisting essentially, expressed in terms of weight percent on the oxide basis, of:
Claim 10
Dependent Claim
39 words
A glass-ceramic body exhibiting high strength and a use temperature up to 1200°C, characterized in that beta-spodumene and/or beta-quartz solid solution constitutes the predominant crystal phase, consisting essentially, expressed in terms of weight percent on the oxide basis, of:
Claim 11
Dependent Claim
37 words
The glass-ceramic body according to claim 8 characterized in that MgO is presentin an amount of 1.5-6%, Li 2 0 is present in an amount of 2-3.5%, and ZrO 2 is present in an amount of 1-3%.
Claim 12
Dependent Claim
44 words
A glass-ceramic body exhibiting high strength, a use temperature up to 1200°C, and oxidation resistance up to 1200°C, characterized in that beta-spodumene and/or beta-quartz solid solution consitutes the predominant crystal phase, consisting essentially, expressed in terms of weight percent on the oxide basis, of:
Claim 13
Dependent Claim
44 words
A glass-ceramic body exhibiting high strength, a use temperature up to 1200°C, and oxidation resistance up to 1200°C, characterized in that beta-spodumene and/or beta-quartz solid solution consitutes the predominant crystal phase, consisting essentially, expressed in terms of weight percent on the oxide basis, of:
Claim 14
Dependent Claim
38 words
The glass-ceramic body according to claim 10 characterized in that MgO is present in an amount of 1.5-6%, Li 2 0 is present in an amount of 2-3.5%, and ZrO 2 is present in an amount of 1-3%.
Claim 15
Dependent Claim
92 words
A method for making the glass-ceramic body of claim 8 exhibiting high strength and a use temperature up to 1200°C, wherein beta-spodumene and/or beta-quartz solid solution constitutes the predominant crystal phase, characterized in comprising the steps of: (a) melting a batch for a glass consisting essentially, expressed in terms of weight percent on the oxide basis, of: (b) simultaneously cooling said melt and forming a glass body of a desired configuration therefrom; and (c) exposing said glass body to a temperature between about 750°C-1200°C for a period of time sufficient to crys-
Claim 16
Dependent Claim
6 words
tallize said glass body in situ.
Claim 17
Dependent Claim
6 words
tallize said glass body in situ.
Claim 18
Dependent Claim
37 words
The method according to claim 12 characterized in that MgO is present in an amount of 1.5-6%, Li 2 0 is present in an amount of 2-3.5%, and ZrO 2 is present in an amount of 1-3%.
Claim 19
Dependent Claim
30 words
The method according to claim 12 characterized in that said glass composition also contains 0.5-3% As 2 0 3 to impart oxidation resistance up to 1200°C to said glass-ceramic body.
Claim 20
Dependent Claim
30 words
The method according to claim 13 characterized in that said glass composition also contains 0.5-3% As 2 O 3 to impart oxidation resistance up to 1200°C to said glass-ceramic body.
References Cited (Backward Citations)
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