Aluminum fiber structure and aluminum composite material

Abstract

An aluminum composite material (1, 2, 3, 4, 5) is a composite formed of an aluminum fiber structure (10) and a composite material (70, 80, 110). The aluminum fiber structure (10) includes aluminum fibers (20) partially bound to each other, and alumina layers 30 are formed on surfaces of the aluminum fibers (20). A plurality of alumina protrusions (40) each having a height larger than a thickness of the alumina layer (30) are formed on surfaces of the aluminum fibers (20) or the alumina layers (30). The alumina protrusions (40) and at least a part of the composite material (70, 80, 110) are in contact with each other.

1 . An aluminum fiber structure comprising
 aluminum fibers partially bound to each other, wherein   alumina layers are formed on surfaces of the aluminum fibers, and   a plurality of alumina protrusions each having a height larger than a thickness of each alumina layer are formed on surfaces of the aluminum fibers or the alumina layers.   
     
     
         2 . The aluminum fiber structure according to  claim 1 , wherein at least a part of the plurality of protrusions are each in contact with the alumina layers of a plurality of the aluminum fibers in a straddling manner. 
     
     
         3 . The aluminum fiber structure according to  claim 1 , wherein the height of each protrusion at the surfaces of the aluminum fibers or the alumina layers ranges from 10 nm to 10 μm. 
     
     
         4 . The aluminum fiber structure according to  claim 1 , wherein the thickness of each alumina layer ranges from 10 nm to 10 μm. 
     
     
         5 . The aluminum fiber structure according to  claim 1 , wherein 20% or more of surfaces of the aluminum fibers on a cross-section of the aluminum fiber structure is covered by the protrusions. 
     
     
         6 . The aluminum fiber structure according to  claim 1 , wherein 40% or more of the surfaces of the aluminum fibers on the cross-section of the aluminum fiber structure is covered by the protrusions in total. 
     
     
         7 . The aluminum fiber structure according to  claim 1 , wherein a plasma-resistant layer is formed on surfaces of the alumina layers and the protrusions. 
     
     
         8 . The aluminum fiber structure according to  claim 7 , wherein the plasma-resistant layer includes metal oxide or aluminum nitride. 
     
     
         9 . The aluminum fiber structure according to  claim 1 , wherein the protrusions are formed by an eluted substance from the aluminum fibers when the aluminum fibers are sintered at 700° C. or higher. 
     
     
         10 . The aluminum fiber structure according to  claim 1 , wherein a space factor of the aluminum fibers in the aluminum fiber structure ranges from 20% to 90%. 
     
     
         11 . An aluminum composite material comprising
 the aluminum fiber structure according to  claim 1  and a composite material which form a composite, wherein   the alumina protrusions and at least a part of the composite material are in contact with each other.