Abstract: A fabrication method for fabricating a pattern for lost pattern casting, comprising at least one insert (10), providing at least two pattern portions (12, 14), said at least two portions being made of a material that can be eliminated, and assembling said at least two pattern portions together around at least a portion of said at least one insert in sealed manner so as to make said pattern (16).

Abstract: A process for manufacturing at least one single-crystal seed that can be used as a starter seed in the manufacture of a single-crystal high-pressure turbine nozzle, with at least one vane between two platforms, by metal casting, is disclosed. The process includes producing a wax pattern that includes a pattern for the nozzle, a pattern for the starter seed, and a pattern for a crude seed; forming a ceramic shell mold from the wax pattern; incorporating a starter seed into the mold; pouring metal into the mold; directionally solidifying the metal in the mold from the starter seed; and separating the crude seed from the nozzle. The starter seed and the crude seed each include a flat face for localizing the crystalline orientations. The crude seed has the same crystallographic structure as the nozzle.

Abstract: The present invention relates to a process for manufacturing at least one single-crystal seed that can be used as a starter seed in the manufacture of a single-crystal high-pressure turbine nozzle, with at least one vane between two platforms, by metal casting, wherein: a wax pattern is produced which comprises: a first element forming the pattern for the nozzle, a second element forming the pattern for the starter seed, including a flat face for localizing the crystalline orientations, and at least a third element incorporating a pattern for the crude seed with a flat face for localizing the crystalline orientations; a ceramic shell mold is formed from said wax pattern and a starter seed, including said flat face for localizing the crystalline orientations, is incorporated into the mold; a metal is poured into the mold; the metal undergoes directional solidification in the mold from the starter seed, so that the crude seed obtained has the same crystallographic structure as the part; and the crude seed o

Abstract: The invention proposes a method for passivating the contact surface of a refractory container made of mullite. Such a method is remarkable in that it comprises the following operations: a. application to the contact surface of a coating comprising 50% to 70% by weight of alumina flour (Al2O3) filler and 30% to 50% of binder, this binder itself comprising 50% to 60% of aluminum chloride AlCl3 dissolved in 40% to 50% of water; b. drying; c. firing of the container in an oxidizing atmosphere between 1450° C. and 1550° C. for at least 20 min. Application to the casting of titanium alloys.