Silicon carbide ceramic

Abstract

An SiC ceramics comprising a metal oxide, the SiC ceramics comprising a surface modification layer containing a silicate, the surface modification layer being derived from a raw material forming the SiC ceramics, which is a matrix.

1 . A silicon carbide ceramics comprising a metal oxide,
 the silicon carbide ceramics comprising a surface modification layer containing a silicate,   the surface modification layer being derived from a raw material forming the silicon carbide ceramics, which is a matrix.   
     
     
         2 . The silicon carbide ceramics according to  claim 1 , wherein the surface modification layer comprises 50 wt % or more of the silicate. 
     
     
         3 . The silicon carbide ceramics according to  claim 2 , wherein the surface modification layer consists of a silicate. 
     
     
         4 . The silicon carbide ceramics according to  claim 1 , wherein the surface modification layer containing a silicate is produced around the surface of the silicon carbide ceramics as a matrix. 
     
     
         5 . The silicon carbide ceramics according to  claim 1 , wherein the metal oxide is at least one metal oxide selected from the group consisting of scandium oxide (Sc 2 O 3 ), yttrium oxide (Y 2 O 3 ), erbium oxide (Er 2 O 3 ), ytterbium oxide (Yb 2 O 3 ), alumina (Al 2 O 3 ), and lutetium oxide (Lu 2 O 3 ). 
     
     
         6 . The silicon carbide ceramics according to  claim 1 , wherein the silicate is at least one silicate selected from the group consisting of scandium silicate (Sc 2 Si 2 O 7 ), yttrium silicate (Y 2 SiO 5 ), erbium silicate (ErSiO 5 ), ytterbium silicate (Yb 2 SiO 5 ), ytterbium silicate (Yb 2 Si 2 O 7 ), aluminum silicate (Al 2 SiO 5 ), and lutetium silicate (LuSiO 5 ). 
     
     
         7 . The silicon carbide ceramics according to  claim 1 , wherein the metal oxide is at least one metal oxide selected from the group consisting of scandium oxide (Sc 2 O 3 ), yttrium oxide (Y 2 O 3 ), erbium oxide (Er 2 O 3 ), ytterbium oxide (Yb 2 O 3 ), and lutetium oxide (Lu 2 O 3 ); and
 the silicate is at least one silicate selected from the group consisting of scandium silicate (Sc 2 Si 2 O 7 ), yttrium silicate (Y 2 SiO 5 ), erbium silicate (ErSiO 5 ), ytterbium silicate (Yb 2 SiO 5 ), ytterbium silicate (Yb 2 Si 2 O 7 ), and lutetium silicate (LuSiO 5 ).   
     
     
         8 . A method for producing a silicon carbide ceramics, comprising:
 (1) a step of dispersing a raw material for forming silicon carbide, and a metal oxide in a dispersion medium;   (2) a step of sintering the dispersion product obtained in step (1); and   (3) a step of heat-treating the sintered product obtained in step (2) to form a surface modification layer containing a silicate on a silicon carbide ceramics as a matrix.   
     
     
         9 . The method according to  claim 8 , wherein the surface modification layer comprises 50 wt % or more of the silicate. 
     
     
         10 . The method according to  claim 9 , wherein the surface modification layer consists of a silicate. 
     
     
         11 . The method according to  claim 8 , wherein step (3) is a step of heat-treating the sintered product obtained in step (2) to form a surface modification layer containing a silicate around the surface of the silicon carbide ceramics as a matrix. 
     
     
         12 . The method according to  claim 8 , wherein the metal oxide is at least one oxide selected from the group consisting of scandium oxide (Sc 2 O 3 ), yttrium oxide (Y 2 O 3 ), erbium oxide (Er 2 O 3 ), ytterbium oxide (Yb 2 O 3 ), alumina (Al 2 O 3 ), and lutetium oxide (Lu 2 O 3 ). 
     
     
         13 . The method according to  claim 8 , wherein the silicate is at least one silicate selected from the group consisting of scandium silicate (Sc 2 Si 2 O 7 ), yttrium silicate (Y 2 SiO 5 ), erbium silicate (ErSiO 5 ), ytterbium silicate (Yb 2 SiO 5 ), ytterbium silicate (Yb 2 Si 2 O 7 ), aluminum silicate (Al 2 SiO 5 ), and lutetium silicate (LuSiO 5 ). 
     
     
         14 . A ceramic fiber reinforced silicon carbide composite material comprising the silicon carbide ceramics according to  claim 1  as a matrix, and ceramic fibers. 
     
     
         15 . The ceramic fiber reinforced silicon carbide composite material according to  claim 14 , wherein the ceramic fiber is at least one ceramic fiber selected from the group consisting of silicon carbide fiber, alumina fiber, and carbon fiber.