Fiber-reinforced ceramic composite material comprising a matrix with a nanolayered microstructure

Abstract

A fiber-reinforced ceramic matrix composite material exhibiting increased matrix cracking strength and fracture toughness is produced by sequentially depositing a plurality of 5-500 nanometer-thick layers of a primary ceramic matrix material phase periodically separated by 1-100 nanometer-thick intermediate layers of a secondary matrix material phase onto the reinforcing fibers upon their consolidation. The resultant nanolayered matrix enhances the resistance to the onset of matrix cracking, thus. increasing the useful design strength of the ceramic matrix composite material. The nanolayered microstructure of the matrix constituent also provides a unique resistance to matrix crack propagation. Through extensive inter-layer matrix fracture, debonding and slip, internal matrix microcracks are effectively diverted and/or blunted prior to their approach towards the reinforcing fiber, thus increasing the apparent toughness of the matrix constituent. This unique toughening mechanism serves to dampen energetic co-planar macrocrack propagation typically observed in conventionally manufactured ceramic matrix composites wherein matrix cracks are usually deflected at the fiber/matrix interphase region.

1 - 12 . (canceled)  
   
   
       13 . A method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material comprising: 
 fabricating a fibrous preform of refractory reinforcing fibers;    depositing a fiber coating material which fully encapsulates the refractory fibers thereof; and    depositing a ceramic matrix material with a nanolayered microstructure comprising a plurality of primary phase layers of a first material and a plurality of secondary phase layers of a second material, wherein the secondary phase layers are interposed between the primary phase layers, and wherein the nanolayered ceramic matrix material encapsulates the coated refractory fibers of the fibrous preform and consolidates the preform into a densified composite.    
   
   
       14 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said fibrous preform is fabricated from an assemblage of refractory fibers produced by a textile fabrication process selected from the group consisting of weaving, braiding, knitting, fiber placement, filament winding, felting, and needling.  
   
   
       15 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein the fiber coating deposited on said fibrous preform has a thickness of 0.05-5.0 micrometers and is produced by a process selected from the group consisting of chemical vapor infiltration (CVI), polymer precursor impregnation/pyrolysis (PIP), reaction formation, and combinations thereof.  
   
   
       16 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein the fiber coating deposited on said fibrous preform is carbon produced by chemical vapor infiltration using a carbon-forming precursor selected from the group consisting of methane, propane, propylene, and mixtures thereof, which is pyrolytically decomposed into carbon at an elevated temperature of 950-1250° C. and at a reduced pressure of 1-250 Torr.  
   
   
       17 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein the fiber coating deposited on said fibrous preform is boron nitride produced by chemical vapor infiltration using a boron nitride-forming precursor selected from the group consisting of boron trichloride, boron triflouride, diborane, and mixtures thereof, which is reduced with a reductant selected from a group of chemical reductants comprising nitrogen, hydrogen, ammonia, and mixtures thereof to form boron nitride at an elevated temperature of 700-1200° C. and at a reduced pressure of 1-250 Torr.  
   
   
       18 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said fibrous preform is first coated with carbon followed by a boron carbide coating produced by chemical vapor infiltration using a boron carbide-forming precursor selected from the group consisting of boron trichloride, boron triflouride, diborane, and mixtures thereof, which is reacted with a carbon-forming precursor selected from a group of chemical reactants comprising methane, propane, propylene, and mixtures thereof to form boron carbide at an elevated temperature of 800-1100° C. and at a reduced pressure of 1-250 Torr.  
   
   
       19 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said fiber coated fibrous preform is consolidated with a nanolayered ceramic matrix material produced by a process selected from the group consisting of chemical vapor infiltration (CVI), polymer precursor impregnation/pyrolysis (PIP), reaction formation, and combinations thereof, which fully encapsulates said coated reinforcing fibers of said fibrous preform for transforming said fibrous preform into a dense, ceramic matrix composite material.  
   
   
       20 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said nanolayered ceramic matrix material is manufactured by the steps comprising: 
 depositing a first layer of a primary phase material with a thickness of between 5 and 500 nanometers;    depositing a second layer of a secondary phase material with a thickness of between 1 and 100 nanometers; and    sequentially repeating steps (a-b) to create a material with a nanolayered microstructure comprising a plurality of primary phase layers of a first material and a plurality of secondary phase layers of a second material, the secondary phase layers interposed between the primary phase layers, wherein the nanolayered ceramic matrix material encapsulates the coated refractory fibers of the fibrous preform and consolidates the preform into a densified composite.    
   
   
       21 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 20 , wherein said primary phase material layers and said secondary phase material layers comprising said nanolayered ceramic matrix material are produced by chemical vapor infiltration.  
   
   
       22 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 20 , wherein said primary phase layers and said secondary phase layers comprising the nanolayered ceramic matrix material are produced by periodic throttling of the respective chemical precursor materials at discrete time intervals during chemical vapor infiltration matrix deposition processing, whereby the selected throttling frequencies are dependent on the respective primary and secondary material deposition rates.  
   
   
       23 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 20 , wherein the chemical vapor infiltration process for depositing said primary phase layers and said secondary phase layers comprising said nanolayered ceramic matrix material is maintained at a constant temperature, whereby the selected processing temperature is dependent on the compatibility for producing both said primary and said secondary material phases.  
   
   
       24 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 20 , wherein the chemical vapor infiltration process for depositing said primary and said secondary phase layers comprising said nanolayered ceramic matrix material is maintained at a constant pressure, whereby the selected processing pressure is dependent on the compatibility for producing both said primary and said secondary material phases.  
   
   
       25 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said plurality of primary phase layers comprising said nanolayered ceramic matrix are silicon carbide produced by chemical vapor infiltration using a silicon carbide-forming precursor selected from the group consisting of methyltrichlorosilane, dimethyldichlorosilane, silicon tetrachloride with methane, and mixtures thereof, which is reacted to form silicon carbide at an elevated temperature of 850-1150° C. and at a reduced pressure of 1-250 Torr.  
   
   
       26 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said plurality of primary phase layers comprising said nanolayered ceramic matrix are silicon nitride produced by chemical vapor infiltration using a silicon nitride-forming precursor selected from the group consisting of silicon tetrachloride, silicon tetraflouride, dichlorosilane, trichlorosilane, and mixtures thereof, which is reduced with a reductant selected from a group of chemical reductants comprising ammonia, nitrogen; hydrogen, and mixtures thereof to form silicon nitride at an elevated temperature of 800-1 100° C. and at a reduced pressure of 1-250 Torr.  
   
   
       27 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said plurality of primary phase layers comprising said nanolayered ceramic matrix are boron carbide produced by chemical vapor infiltration using a boron carbide-forming precursor selected from the group consisting of boron trichloride, boron triflouride, diborane, and mixtures thereof, which is reacted with a carbon-forming precursor selected from a group of chemical reactants comprising methane, propane, propylene, and mixtures thereof to form boron carbide at an elevated temperature of 800-1100° C. and at a reduced pressure of 1-250 Torr.  
   
   
       28 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said plurality of secondary phase layers comprising said nanolayered ceramic matrix are carbon produced by chemical vapor infiltration using a carbon-forming precursor selected from the group consisting of methane, propane, propylene, and mixtures thereof, which is pyrolytically decomposed into carbon at an elevated temperature of 950-1250° C. and at a reduced pressure of 1-250 Torr.  
   
   
       29 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said plurality of secondary phase layers comprising the nanolayered ceramic matrix are silicon produced by chemical vapor infiltration using a silicon-forming precursor selected from the group consisting of dichlorosilane, trichlorosilane and mixtures thereof, which is reduced with hydrogen to form silicon at an elevated temperature of 950-1250° C. and at a reduced pressure of 1-250 Torr.  
   
   
       30 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said plurality of secondary phase layers comprising the nanolayered ceramic matrix are boron nitride produced by chemical vapor infiltration using a boron nitride-forming precursor selected from the group consisting of boron trichloride, boron triflouride, diborane, and mixtures thereof, which is reduced with a reductant selected from a group of chemical reductants comprising nitrogen, hydrogen, ammonia, and mixtures thereof to form boron nitride at an elevated temperature of 700-1200° C. and at a reduced pressure of 1-250 Torr.  
   
   
       31 . The method for manufacturing a fiber-reinforced nanolayered ceramic matrix composite material recited in  claim 13 , wherein said plurality of secondary phase layers comprising the nanolayered ceramic matrix are silicon nitride produced by chemical vapor infiltration using a silicon nitride-forming precursor selected from the group consisting of silicon tetrachloride, silicon tetraflouride, dichlorosilane, trichlorosilane, and mixtures thereof, which is reduced with a reductant selected from a group of chemical reductants comprising ammonia, nitrogen; hydrogen, and mixtures thereof to form silicon nitride at an elevated temperature of 800-1100° C. and at a reduced pressure of 1-250 Torr.  
   
   
       32 - 34 . (canceled)