Part consisting of a ceramic material, comprising a base and a wall
View Patent ↗A part made of a ceramic material, including a portion forming a base and a portion forming a wall, wherein the base consists of a low-porosity ceramic material and the wall is obtained by powder sintering and includes an envelope and a core, the core being within the envelope, the porosity of the core being higher than that of the base and increasing the further it is from the base.
1. A turbine blade made of ceramic material, comprising:
a root; and
an airfoil,
wherein the root is made of ceramic material and the airfoil is obtained by ceramic powder sintering, and
wherein the airfoil includes an envelope and a core, the core being positioned within the envelope and a porosity of the core being greater than a porosity of the root, the porosity of the core increasing along the airfoil along an axis in a direction of centrifugal forces which the turbine blade is subjected to during operation.
2. The turbine blade according to claim 1 , wherein the root is produced by ceramic powder sintering.
3. The turbine blade according to claim 1 , the porosity of the material forming the root being less than 3%.
4. The turbine blade according to claim 1 , wherein the porosity of the core is greater than 5%.
5. The turbine blade according to claim 4 , wherein the porosity of the core is between 10 and 50%.
6. The turbine blade according to claim 1 , wherein the core comprises a porous material made of ceramic grains which are bound by partial sintering.
7. The turbine blade according to claim 1 , wherein the core comprises cavities separated by partitions, a material forming the partitions having a porosity of less than 3%.
8. The turbine blade according to claim 1 , wherein the core has portions having different cavities, sizes of the cavities increasing along the airfoil along the axis.
9. The turbine blade according to claim 1 , further comprising a heel at a free end of the airfoil, a porosity of the heel being lower than the porosity of the core.
10. The turbine blade according to claim 9 , wherein the heel includes sealing strips.
11. A method for manufacturing a turbine blade according to claim 1 , comprising:
forming the airfoil using a sintering tray containing powder with which the root is flush at a beginning of the forming; and
selective sintering of the powder in successive layers by a laser beam or electron beam, the successive layers being obtained by making the turbine blade move progressively downwards in the sintering tray.
12. The method according to claim 11 , including producing the root separately by powder sintering and then forming the airfoil by depositing successive layers of ceramic powder and binding the root and the airfoil by sintering.