Office National D'etudes Et De Recherches Aerospatiales

Frederic Rousseau

Marie-Pierre Bacos

Daniel Morvan

Odile Lavigne

Catherine Rio

Marie-Helene Vidal-Setif

The invention relates to a method for repairing a thermal barrier of a component comprising a substrate coated with such a thermal barrier, said substrate being made of a high-performance alloy, said thermal barrier being adhered to the alloy and having lower thermal conductivity than the alloy, the thermal barrier including at least one ceramic, one region of the thermal barrier being a region to be repaired, wherein said method includes the following steps: a) defining the region to be repaired, using a mask which protects the other regions of the thermal barrier; b) injecting a carrier gas loaded with droplets of ceramic precursor into a plasma discharge inside a plasma chamber of a plasma reactor containing the component to be repaired, while making the concentration of ceramic precursor in the carrier gas dependent on at least one parameter of the reactor selected from among: the pressure of the plasma chamber, the power of the plasma generator and the diameter of the precursor droplets, in order to control the state&#x2014;liquid, gel or solid&#x2014;of the ceramic precursor having an effect on the region to be repaired; c) injecting a gas not loaded with ceramic precursor into a plasma discharge within the plasma chamber, steps b) and c) being repeated.

Method for locally repairing thermal barriers

The invention relates to a method and system for forming a layer of oxide on a pervious component made of a material or a stack of materials that are stable at 400&#xb0; C., said component including an outer surface to be coated and at least one pore with a diameter of 50 to 1000 &#x3bc;m leading onto said outer surface. Said method includes the following steps: a) injecting a carrier gas loaded with droplets of at least one precursor of the oxide into a low-pressure plasma inside an enclosure of a plasma reactor housing the component to be coated, and injecting a fluid passing through the pervious component and flowing in gaseous state through said at least one pore with a flow opposite to that of the carrier gas in the plasma chamber in order to avoid the clogging of the pore, the pressure and the mass flow of said fluid upstream of the pervious component being such that the pressure of the gas at the outlet of the at least one pore is higher than the pressure in the plasma chamber, and the injection mass flow of the fluid passing through the pervious component is: &#x3b1;) less than or equal to the mass low of the carrier gas loaded with precursor of the oxide injected into the plasma chamber, and &#x3b2;) greater than or equal to the product of the mass flow of the carrier gas loaded with precursors of the oxide injected into the plasma chamber by the ration between the total surface of the open pores of the pervious component and the surface of the passage section of the plasma chamber, thus, the speed of the gas at the outlet of the at least one pore is no lower than the intake speed of the carrier gas loaded with at least one precursor of the oxide in, non-preferentially, the liquid, gel or solid state thereof, on the outer surface of the component; b) injecting a carrier gas not loaded with a precursor of the oxide into a plasma inside the plasma chamber, wherein the injection of the fluid passing through the pervious component is maintained and steps a) and b) are repeated, such as to form said oxide on the outer surface, the diameter of the at least one pore being preserved.

Growing community of inventors

Esclavolles Lurey, France

Frederic Rousseau