Method of Producing Carbon Fiber Reinforced Ceramic Matrix Composites

Abstract

The present invention relates to a method of producing carbon fiber reinforced ceramic matrix composites, the method of producing carbon fiber reinforced ceramic matrix composites according to the present invention is characterized in that the method comprises the steps of: producing a carbon fiber reinforced resin composite that is molded with a mixture in which carbon fibers and polymer precursors containing carbon are mixed; producing a carbon fiber reinforced carbon composite by depositing pyrolytic carbon during a rapid thermal gradient chemical vapor infiltration process while increasing the deposition speed in a direction from the inside to the outside by performing a thermal treatment on said carbon fiber reinforced resin composite at high temperature; and infiltrating liquid-phase silicon into the pores of said carbon fiber reinforced carbon composite. The method of producing carbon fiber reinforced ceramic matrix composites according to the present invention as described above has the effect of improving the properties of carbon fiber reinforced ceramic matrix composites, and it is possible to deposit a pyrolytic carbon layer at a deposition speed 5-10 times faster than other conventional chemical vapor infiltration processes, thereby showing a remarkably improved effect in terms of manufacturing process, time, and cost.

1 . A method of producing carbon fiber reinforced ceramic matrix composites comprising the steps of:
 producing a carbon fiber reinforced resin composite that is molded with a mixture in which carbon fibers and polymer precursors containing carbon are mixed;   producing a carbon fiber reinforced carbon composite by depositing pyrolytic carbon during a rapid thermal gradient chemical vapor infiltration process while increasing the deposition speed in a direction from the inside to the outside by performing a thermal treatment on said carbon fiber reinforced resin composite at high temperature; and   infiltrating liquid-phase silicon into the pores of said carbon fiber reinforced carbon composite.   
   
   
       2 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 1 , wherein said mixture includes 10-60 wt % of said carbon fibers, and 30-60 wt % of said polymer precursors containing carbon. 
   
   
       3 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 2 , wherein said mixture includes less than 30 wt % silicon carbide powder, and less than 30 wt % carbon powder. 
   
   
       4 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 2  or  3 , wherein said carbon fiber reinforced resin composite is stacked with said mixture and carbon fabrics alternately. 
   
   
       5 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 4 , wherein said green body is formed with a first surface layer for preventing carbon fibers from reacting with silicon by means of said mixture that has been mixed during the mixing process, and said first surface layer is formed with a ceramic matrix layer including silicon carbide and silicon by chemically reacting with said liquid-phase silicon in the step of infiltrating said liquid-phase silicon. 
   
   
       6 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 1 , wherein said green body undergoes a thermal treatment in a range of 900-2,200° C. in inert gas atmosphere, and then a pyrolytic carbon matrix layer as a second surface layer is deposited on the first surface layer in a deposition step through said rapid thermal gradient chemical vapor infiltration process. 
   
   
       7 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 1 , wherein the deposition step by said rapid thermal gradient chemical vapor infiltration process is performed in a range of pyrolytic reaction temperatures 700-1,200° C. and reaction pressures 188-1,130 torr using hydro-carbon gas. 
   
   
       8 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 1 , wherein a deposition region is divided into a plurality of regions from the inside to the outside, and individual regions are deposited at different speeds from one another in a deposition step through said rapid thermal gradient chemical vapor infiltration process. 
   
   
       9 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 1 , wherein said deposition region is deposited from the inside to the outside at a deposition speed in a range of 0.5-3.0 mm/hr. 
   
   
       10 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 1 , wherein said carbon fiber reinforced carbon composite has 1.0-1.7 g/cm 3  apparent density, and 5-30% of open pores that are used for in-filtrating paths of said liquid-phase silicon. 
   
   
       11 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 1 , wherein the step of infiltrating liquid-phase silicon is performed by stacking said carbon fiber reinforced carbon composite on silicon powder, maintaining a pressure less than 100 torr within a reactor, and then heating it at the silicon melting point more than 1,410° C., thereby infiltrating liquid-phase silicon into a preform while chemically reacting with a plurality of carbon layers. 
   
   
       12 . A method of producing carbon fiber reinforced ceramic matrix composites comprising the steps of:
 producing a carbon felt preform;   producing a carbon fiber reinforced carbon composite by depositing said carbon felt preform through a rapid thermal gradient chemical vapor infiltration process while increasing the deposition speed from the inside to the outside; and   infiltrating liquid-phase silicon into the pores of said carbon fiber reinforced carbon composite.   
   
   
       13 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 12 , wherein said carbon felt preform is any one of carbon-based fibers, such as oxyphene, phene, rayon, pitch-based, etc. 
   
   
       14 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 12 , wherein said carbon felt preform has mat laminates with quasi-isotropic orientations, such as 0/+60/−60°, and it is reinforced with carbon fibers less than 10 mm in the Z-direction. 
   
   
       15 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 12 , wherein said carbon felt preform is deposited with a pyrolytic layer having 5-100   in thickness by means of a deposition step through said rapid thermal gradient chemical vapor infiltration process. 
   
   
       16 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 12 , wherein carbon fibers are reinforced in the three X, Y and Z axes by impregnating liquid-phase silicon into said carbon fiber reinforced carbon composite in the step of infiltrating liquid-phase silicon. 
   
   
       17 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 12 , wherein the deposition step by said rapid thermal gradient chemical vapor infiltration process is performed in a range of pyrolytic reaction temperatures 700-1,200° C. and reaction pressures 188-1,130 torr using hydro-carbon gas. 
   
   
       18 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 12 , wherein a deposition region is divided into a plurality of regions from the inside to the outside, and individual regions are deposited at different speeds from one another in a deposition step through said rapid thermal gradient chemical vapor infiltration process. 
   
   
       19 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 12 , wherein said deposition region is deposited from the inside to the outside at a deposition speed in a range of 0.5-3.0 mm/hr. 
   
   
       20 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 12 , wherein said carbon fiber reinforced carbon composite has 1.0-1.7 g/cm 3  apparent density, and 5-30% of open pores that are used for infiltrating paths of said liquid-phase silicon. 
   
   
       21 . The method of producing carbon fiber reinforced ceramic matrix composites according to  claim 12 , wherein the step of infiltrating liquid-phase silicon is performed by stacking said carbon fiber reinforced carbon composite on silicon powder, maintaining a pressure less than 100 torr within a reactor, and then heating it at the silicon melting point more than 1,410° C., thereby infiltrating liquid-phase silicon into a carbon felt preform while chemically reacting with a plurality of carbon layers.