SILICON CARBIDE CERAMIC

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.