Casting core

Abstract

A casting core includes a main portion made of molybdenum or a molybdenum alloy, and, at the surface of the main portion, at least two protuberances made of a refractory material, the whole of the main portion and the protuberances being covered with an anti-oxidation coating.

1 . A casting core comprising a main portion made of molybdenum or a molybdenum alloy, and, at a surface of the main portion, at least two protuberances made of a refractory material, the whole of the main portion and the at least two protuberances being covered with an anti-oxidation coating, the refractory material of the at least two protuberances being a ceramic. 
     
     
         2 . The casting core according to  claim 1 , wherein the anti-oxidation coating comprises, from the core outwards, at least on adhesion layer and one protective layer, the adhesion layer being selected from a layer of titanium carbonitride TiCN, titanium carbide TiC, titanium nitride TiN, silicon carbide SiC, hafnium carbide HfC, or aluminium nitride AlN and the protective layer being a layer of alumina Al 2 O 3 . 
     
     
         3 . The casting core according to  claim 1 , wherein the at least two protuberances are formed by a single refractory material rod passing through the main portion of the core from one side to the other. 
     
     
         4 . The casting core according to  claim 3 , wherein the refractory material of the refractory material rod is selected from alumina or zirconia. 
     
     
         5 . The casting core according to  claim 1 , wherein of the main portion of the core has the shape of the cooling circuits of a turbomachine blade. 
     
     
         6 . A process for manufacturing a casting core comprising:
 forming a main portion of the core made of molybdenum or molybdenum alloy in the desired shape;   disposing at least two protuberances made of refractory material at the surface of the main portion, the refractory material of the protuberances being a ceramic;   coating the main portion and the protuberances with an anti-oxidation coating.   
     
     
         7 . The manufacturing process according to  claim 6 , wherein the disposing of the at least two protuberances is achieved by shrinking a refractory material rod in a through-opening of the main portion. 
     
     
         8 . The manufacturing process according to  claim 6 , wherein the core is coated by a chemical vapour deposition or physical vapour deposition process. 
     
     
         9 . The manufacturing process according to  claim 6 , wherein the main portion is formed by additive manufacturing or by injection moulding of metal. 
     
     
         10 . A process for manufacturing a hollow part made of metal material by casting, comprising:
 disposing a casting core according to  claim 1  in a casting mould, the casting core being disposed in the mould such that the protuberances are in contact with the mould;   pouring a molten metal material into the moulding cavity of the mould comprising the core; and   shakeout of the mould and removal of the core.