Onera (Office National D'etudes Et De Recherches Aerospatiales)

Office National D'etudes Et De Recherches Aerospatiales

Snecma Moteurs

Safran Aircraft Engines

Onera

Marie-Pierre Bacos

Pierre J Josso

Jérôme Brossier

Justine Menuey

Serge Naveos

Daniel Morvan

Florin Paun

Frederic Rousseau

Jason Nadler

Catherine Rio

Odile Lavigne

Pascal Fabrice Bilhe

Annie Pasquet

Jason Hayes Nadler

Marie-Helene Vidal-Setif

Stéphane Gasser

Carine Hoffmann

Benoît Girard

Eric Berger

Myriam Douin

Ariel Moriel

Alexandra Boyer

Aurélie Gregoire

Sébastien Mercier

Marie-Hélène Vidal-Setif

Ariel Morel

Sebastien Mercier

Aurelie Gregoire

Stephane Gasser

Pascal Bilhe

Frédéric Rousseau

The invention relates to a method for producing a nickel aluminide coating on a metal substrate. The method includes the following steps: a) coating the substrate with a nickel deposit; b) applying an aluminum sheet onto the nickel deposit from step a) so as to form an assembly made up of the substrate coated with the nickel deposit and the aluminum sheet; and c) subjecting said assembly to heat treatment at a temperature that is lower than the melting point of aluminum, and at a low pressure so as to induce a reaction between the aluminum and the nickel and thus form a &#x3b2;-NiAl nickel aluminide layer mounted on a nickel layer. The invention is particularly of use for protecting the materials used in turbines of aircraft engines.

Method for producing a nickel aluminide coating on a metal substrate, and part having one such coating

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.

Method and system for depositing oxide on a porous component

The method according to the invention comprises the following operations:

Process for protecting the surface of a substrate of intermetallic alloy with a titanium aluminide base against corrosion

The invention relates to a method for forming a protective coating against high-temperature oxidation on a surface of a refractory composite material based on silicon and niobium, wherein chromium present on the surface to be protected is reacted with a reactive gas which contains silicon and oxygen in order to produce a composite coating having two phases, a first phase of which is an oxide phase based on silica which has viscoplastic properties and a second phase of which is based on silicon, chromium and oxygen, and wherein the first phase and second phase are coalesced at high temperature, which allows a protective coating to be formed in which the second phase acts as a reservoir to reform, during operation, the first phase by means of reaction with an oxidising gas. The invention is preferably used in the field of aeronautical engines.

Method for forming a protective coating against high-temperature oxidation on a refractory composite material based on silicon and niobium

The invention relates to a method of producing and joining superalloy balls by means of brazing and to objects produced with such joints. According to one aspect of the invention, an alloy powder covered with a brazing solder is bonded to a spherical core and subsequently transformed into a continuous alloy layer by means of brazing.

Method of producing and joining superalloy balls by means of brazing and objects produced with such joints

A structural element used for attenuating aviation turbine noise is provided with pores () embodied in the form of cylindrical channels which are open on the first ends inside the turbine housing and closed on the opposite ends thereof, wherein the diameter (D) of each channel ranges approximately from 0.1 to 0.3 mm, each channel is remote at least along one part of the length thereof from the closest neighbors at a minimum distance ranging approximately from 0.02 to 0.3 mm and the ratio between the channel length and diameter thereof is of the order of 10.

Porous metal bodies used for attenuating aviation turbine noise

The invention relates to a method of brazing a Ti&#x2014;Al alloy. According to the invention, a layer of nickel () is disposed between a part () which is made from titanium aluminide and a brazing sheet (), such as to enable: the aforementioned part () to be brazed to another metallic material () without the aluminium diffusing from one to the other; and a stable link with good mechanical strength to be produced. The invention can be used for the assembly of aircraft engine parts which are made from titanium aluminide and nickel-based superalloy.

Method of brazing a Ti-Al alloy

This relates to an improvement to the process of aluminization or activated cementation in which a donor cement containing the aluminium is attacked at high temperature and in a neutral or reducing atmosphere by a gaseous ammonium halide to form a gaseous aluminium halide which decomposes on contact with a nickel-based substrate depositing aluminium metal thereon. According to the invention the aluminium halide is at least partly replaced by a zirconium halide leading to the inclusion of zirconium in the deposit. Improvement in the protection of the hot parts of aircraft engines made of nickel-based superalloy. No figure is to be published.

Process for forming a protective coating containing aluminium and zirconium on a metal

Hollow metal spheres are heated in a high vacuum in the presence of an organic substance, at a temperature at least equal to the melting point of a eutectic between carbon and the metallic constituents of the said spheres.

Process for the pressureless sintering of metal alloys; and application to the manufacture of hollow spheres

In order to protect a monocrystalline superalloy rich in rhenium against corrosion whilst avoiding the formation of progressive secondary reaction zones, a layer () formed of tungsten and cobalt is deposited on its surface before aluminisation treatment.

Protective coating for monocrystalline superalloy

The invention concerns a method wherein the substrate () to be coated is immersed in an autocatalytic chemical deposit bath (), for example nickel, contained in a stainless steel vessel () and wherein can be optionally mixed a suspended MCrAlY alloy, so as to form a metal deposit (nickel) wherein are optionally included powder particles. The invention is characterised in that, to provide a prolonged operation of the bath, it consists in measuring with a voltmeter () the difference of potential between the substrate () and a reference electrode () immersed in the bath (), and in imposing between the substrate () and the vessel () an electric current produced by a generator (), said current being adjusted by a regulator () so as to maintain said potential difference at a selected value.

Method for forming on a metallic substrate a sulphur-free metallic coating

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Antony, France

Marie-Pierre Bacos