Ductile metal ligament fiber coatings for ceramic composites

Abstract

An improved method for fabricating ceramic composites, particularly single crystal alumina fiber and yttrium-aluminum garnet (YAG) matrix composites. The method of this invention comprises the steps of (a) coating the fiber with a metal which is stable under oxidizing conditions, such as Pd, (b) coating the metal-coated fiber with a fugitive phase, such as Mo, (c) incorporating the coated fiber into a matrix material, (d) densifying the fiber-matrix into a composite and (e) heat treating the composite under oxidizing conditions to remove the fugitive phase.

I claim: 
     
       1. An improved method for fabricating ceramic composites of ceramic reinforcing fiber and ceramic matrix, which comprises the steps of (a) coating the fiber with a metal which is stable under oxidizing conditions from about room temperature to about 1800° C., (b) coating the metal-coated fiber with a fugitive phase, (c) incorporating the coated fiber into a matrix material, (d) densifying the fiber-matrix into a composite and (e) heat treating the composite under oxidizing conditions to remove the fugitive phase. 
     
     
       2. The method of claim 1 wherein said metal is selected from the group consisting of palladium, platinum and rhodium. 
     
     
       3. The method of claim 1 wherein said fugitive phase is carbon or molybdenum. 
     
     
       4. The method of claim 1 wherein said fiber is continuous single crystal alumina fiber. 
     
     
       5. The method of claim 1 wherein said matrix is yttrium-aluminum garnet.