Reaction inhibited-silicon carbide fiber reinforced high temperature glass-ceramic composites

• US 4,485,179 A
• Filed: 05/20/1982
• Issued: 11/27/1984
• Est. Priority Date: 05/20/1982
• Status: Expired due to Fees

• Current Assignee: Corning Glass Works Inc. (Corning Incorporated), United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Taylor, Mark P., Brennan, John J., Chyung, Kenneth
• Primary Examiner(s): Bell, Mark
• Application Number:
  US06/380,458
• Time in Patent Office: 922 Days
• Field of Search: 501/88, 501/89, 501/95, 501/32, 501/4, 501/5, 501/7, 428/114, 428/367, 428/398, 428/428, 428/432, 428/698, 428/902
• US Class Current: 501/32
• CPC Class Codes: C03C 10/00 Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
• CPC Class Codes: C03C 10/0027 containing SiO2, Al2O3, Li2O as main constituents
• CPC Class Codes: C03C 14/002 the non-glass component being in the form of fibres, filaments, yarns, felts or woven material
• CPC Class Codes: C03C 2214/02 Fibres; Filaments; Yarns; Felts; Woven material
• CPC Class Codes: C03C 2214/03 surface treated, e.g. coated
• CPC Class Codes: C03C 2214/20 Glass-ceramics matrix
• CPC Class Codes: Y10S 428/902 High modulus filament or fiber

Abstract

A silicon carbide fiber reinforced glass-ceramic matrix composite is disclosed having high strength, fracture toughness, and improved oxidative stability even at high temperature 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 Li₂ O in the matrix with MgO results in an even higher temperature stable composite, e.g., up to about 1200° C.

Claims

1. A silicon carbide fiber reinforced glass-ceramic composite exhibiting use temperatures in excess of 1000°

C. consisting essentially of about 15% to about 70% by volume silicon carbide fibers implanted within a glass-ceramic matrix consisting essentially of, expressed in terms of weight percent on the oxide basis, about

space="preserve" listing-type="tabular">______________________________________ Li.sub.2 O 1.5-5 Al.sub.2 O.sub.3 15-25 SiO.sub.2 60-75 As.sub.2 O.sub.3 0.5-3 Ta.sub.2 O.sub.5 0-10 Nb.sub.2 O.sub.5 0-10 Ta.sub.2 O.sub.5 and/or Nb.sub.2 O.sub.5 1-10 ZrO.sub.2 1-3 MgO 0-10 ______________________________________

said fibers having a reaction-inhibiting, diffusion barrier coating of niobium carbide and/or tantalum carbide thereon.

2. A composite according to claim 1 exhibiting use temperatures up to 1200°

C., wherein Li₂ O is present in an amount of 2-3.5%, and MgO is present in an amount of 1.5-6%.