摘要:
A process for depositing a ceramic layer on a metal substrate for producing a thermal barrier, the process including depositing the ceramic in a columnar structure. The deposition is carried out through a grid pierced with holes, which is positioned parallel to a surface of the substrate so as to produce ceramic columns separated from one another by a space. The process can further include a subsequent depositing of an isotropic ceramic layer in the spaces.
摘要:
Process for depositing a coating for protection against oxidation and against hot corrosion on a superalloy substrate, and coating obtainedThe present invention relates to a process for depositing a coating for protection against oxidation and against hot corrosion on a metallic superalloy substrate (1), characterized by the fact that it comprises the deposition of the following successive layers on the substrate, a first layer of aluminium and of at least one element capable of being alloyed with sulphur, a second layer of a material that isolates said element capable of being alloyed with sulphur. The element capable of being alloyed with sulphur is chosen from the reactive elements: zirconium, hafnium, yttrium, silicon, and the rare earth elements: cerium, lanthanum, gadolinium.The invention also relates to the coating thus formed.
摘要:
A ceramic heat barrier coating is deposited on a substrate so that the coating has a columnar growth pattern which is interrupted and repeated a number of times throughout its thickness by successive regermination of the ceramic deposit. The regermination is obtained by a vapor phase deposition process wherein a polluting gas is introduced intermittently during the deposition of the ceramic. The resulting ceramic coating has a lower thermal conductivity than conventional columnar ceramic coatings.
摘要:
A method of locally repairing parts coated with a thermal barrier including a ceramic outer layer and a metal underlayer of alumina-forming alloy for protecting the substrate against oxidation and for bonding with the ceramic outer layer, includes: defining the zone for repair with a mechanical mask adapted to the shape of the part and the zone for repair; scouring the zone for repair so as to remove the ceramic, the alumina layer, and the damaged portions of the underlayer; supplying materials for repairing the underlayer to the repair zone by subjecting the partially-scoured part to metal deposition by use of an electrical current; and subjecting the part to a heat treatment in order to enable the added metals to diffuse into the remaining underlayer in the repair zone for repair and to enable a surface film of alumina to form. After the underlayer has been reconstituted, the zone for repair is again defined by a mechanical mask and a new ceramic layer is deposited thereon.
摘要:
A ceramic heat barrier coating is deposited on a substrate so that the coating has a columnar growth pattern which is interrupted and repeated a number of times throughout its thickness by successive regermination of the ceramic deposit. The regermination is obtained by a vapour phase deposition process wherein a polluting gas is introduced intermittently during the deposition of the ceramic. The resulting ceramic coating has a lower thermal conductivity than conventional columnar ceramic coatings.