Abstract: 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 ?-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.

Abstract: The invention relates to a process for fabricating a high-precision object made of at least one inorganic material, comprising the following steps: using a high-resolution photolithography process, employing X-rays or UV rays depending on the desired degree of precision, in a chosen direction Z, to form a negative mold, which does not deform at the microscale during the steps of the process, in a material able to withstand a step for forming the object by dry deposition and capable of either being removed without altering the object fabricated or being separated from said object; choosing, independently of the normal redox potential of its constituent elements, at least one inorganic material from the set of materials that can be deposited by dry deposition and that allow the object to be fabricated to meet its thermomechanical and environmental specifications; and forming, by means of the non-deformable negative mold, the object to be fabricated by dry deposition of said at least one inorganic material, ther

Abstract: The invention relates to a method for producing a nickel aluminide coating on a metal substrate. Said 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 ?-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.

Abstract: Method, apparatus, and system for preparing a cellular material based on hollow metal beads. According to the description, at least one bead chain in which said hollow metal beads are linked to one another in pairs by means of an articulation is used as elementary structure constituting the cellular material.

Abstract: The invention relates to a process for fabricating a high-precision object made of at least one inorganic material, comprising the following steps: using a high-resolution photolithography process, employing X-rays or UV rays depending on the desired degree of precision, in a chosen direction Z, to form a negative mould, which does not deform at the microscale during the steps of the process, in a material able to withstand a step for forming the object by dry deposition and capable of either being removed without altering the object fabricated or being separated from said object; choosing, independently of the normal redox potential of its constituent elements, at least one inorganic material from the set of materials that can be deposited by dry deposition and that allow the object to be fabricated to meet its thermomechanical and environmental specifications; and forming, by means of the non-deformable negative mould, the object to be fabricated by dry deposition of said at least one inorganic material, th

Abstract: A method for forming a protective coating containing aluminum on the surface of a metal part, wherein the part is contacted with a carburizer made of an aluminum alloy, at a treatment temperature and in a chamber, the atmosphere of which contains an active gas which reacts with the carburizer to form a gaseous aluminum halide, which decomposes upon contacting the part while depositing aluminum metal thereon. In the method the aluminum alloy of the carburizer includes at least one element, zirconium and/or hafnium, the active gas reacting with the carburizer to also form a halide of the reactive element which decomposes upon contacting the part while depositing the element thereon at the same time as the aluminum.

Abstract: The method according to the invention comprises the following operations: a) prepare a substrated formed of the said intermetallic alloy; b) deposit a coating of gold on the surface to be protected of the substrate; and c) subject the substrate thus equipped with the gold coating to annealing in controlled conditions in order to bring about limited diffusion of the gold into the surface to be protected. The invention is applicable in particular to parts of gas turbines, e.g. parts of aircraft engines.

Abstract: 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.

Abstract: 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.

Abstract: A method for forming a protective coating containing aluminum on the surface of a metal part, wherein the part is contacted with a carburizer made of an aluminum alloy, at a treatment temperature and in a chamber, the atmosphere of which contains an active gas which reacts with the carburizer to form a gaseous aluminum halide, which decomposes upon contacting the part while depositing aluminum metal thereon. In the method the aluminum alloy of the carburizer includes at least one element, zirconium and/or hafnium, the active gas reacting with the carburizer to also form a halide of the reactive element which decomposes upon contacting the part while depositing the element thereon at the same time as the aluminum.

Abstract: 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.

Abstract: Method, apparatus, and system for preparing a cellular material based on hollow metal beads. According to the description, at least one bead chain in which said hollow metal beads are linked to one another in pairs by means of an articulation is used as elementary structure constituting the cellular material.

Abstract: 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.

Abstract: A structural element used for attenuating aviation turbine noise is provided with pores (1, 2) 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 102.

Abstract: A structural element used for attenuating aviation turbine noise is provided with pores (1, 2) 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 neighbours 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 102.

Abstract: The invention relates to a method of brazing a Ti—Al alloy. According to the invention, a layer of nickel (2) is disposed between a part (1) which is made from titanium aluminide and a brazing sheet (3), such as to enable: the aforementioned part (1) to be brazed to another metallic material (4) 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 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.

Abstract: In order to protect a monocrystalline superalloy rich in rhenium against corrosion whilst avoiding the formation of progressive secondary reaction zones, a layer (3) formed of tungsten and cobalt is deposited on its surface before aluminisation treatment.