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: An inertial sensor for measuring information relating to rotation in three orthogonal axes, comprising a support and a vibrating sensitive element secured to the support; said sensitive element having a deformable frame and at least two deformable projections which extend in a plane (X-Y); wherein the inertial sensor extends in the same plane; the deformable frame and said at least two deformable projections have a plane of symmetry parallel to the plane; said at least two projections are rectilinear beams which have an approximately square cross section, are not collinear and are preferably approximately orthogonal to one another; each of said deformable beams being connected by only one end to the deformable frame at a location at which the amplitude of the primary vibration mode is at a maximum; and in that said sensor has a device for detecting each of the secondary vibration modes.

Abstract: An optical probe for measuring physical and chemical characteristics of a transparent fluid medium during flow comprises two fingers parallel to one another and to the flow. Each finger consists of a solid bar of transparent material, in which a light beam propagates and is reflected on an end face of the bar, said face being situated upstream in the flow. Such an optical probe may be reduced in size, and provides results which are less sensitive to disturbances of the flow that are caused by the probe itself.

Abstract: According to the invention, the system for determining, in real time, flight parameters of an aircraft, in the course of a flight of the latter, comprises an extended Kalman filter (10) which is configured on the basis of flight mechanics equations establishing a dependency relationship between at least two preselected flight parameters of said aircraft to be estimated and which is formed so as to deliver, during a flight of said aircraft, joint estimations of said selected flight parameters.

Abstract: The present disclosure is directed to a rotary wing rotor comprising one or more blades. Each blade has a torsion frequency around its span being substantially equal to a rotation frequency (?) of the rotor; torsion means twist to the rotation frequency of the rotor, in synchronization with said rotation; and comprising a material configured to dampen the torsion resonance, so as to avoid the resonance divergence.

Abstract: The invention relates to a tip indenting apparatus for testing a block of material, characterized in that it comprises: a holder for the tip and a holder for a block of a material to be punched or scratched, said tip holder and said block holder each comprising a solid body made of heat conducting material; securing means for removably securing the tip or the block in thermal-conducting contact to said solid body; an annular sheath having a shape corresponding to that of said solid body and in which said solid body is provided; heating means comprising at least one electric heater; and means for assembling the solid body and the heating means; wherein, during a test, the tip can be heated at a predetermined temperature, in particular a temperature essentially equal to that of the block of material to be tested.

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 process for measuring speed or vibration characteristics using a LIDAR device allows the separation of a useful contribution and an interfering contribution in a backscattered signal. To this purpose, a phase characteristic of an optical wave emitted in the direction of a target volume is modulated. The interfering contribution, which originates from a source at a distance from the target volume, appears with variable shifts of said phase characteristic in a heterodyne detection signal. An accumulation then isolates the useful contribution, from which a result is obtained for the speed or vibration measurement. The process can be implemented with a frequency modulation or phase modulation of the optical wave.

Abstract: The method comprises positioning a diffraction grating with a two-dimensional meshing on the path of the beam to be analyzed and processing at least two interferograms of at least two different colors, each interferogram being obtained in a plane from two sub-beams with different diffraction orders. The invention can be used to analyze and correct divided wavefronts.

Abstract: A method and a system for analyzing the wavefront of a light beam, wherein a diffraction grating is arranged in a plane perpendicular to the light beam to be analyzed and optically conjugated to the analysis plane. Different emerging beams of the grating interfere to generate an image having deformations linked to the gradients of the wavefront to be analyzed. The method is characterized in that the grating carries out the multiplication of an intensity function which is implemented by a two-dimensional grating with hexagonal meshing of surface S transmitting the light of the beam to be analyzed into plural emerging beams arranged in a hexagonal meshing, by an phase function which is implemented by a two-dimensional grating with hexagonal meshing of surface 3S which introduces a phase shift close to 2?/3 (modulo 2?) between two adjacent secondary beams.

Abstract: The invention relates to an elongated, torsion-deformable aerodynamic element, in which the upper surface (2) is continuous while the lower surface (3) comprises a longitudinal slot (6) in the direction of the span and in the vicinity of the leading edge (4). Furthermore, an actuator device (14) inside said aerodynamic element is capable of sliding the edges (6A and 6R) of the slot (6) relative to each other.

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: The present invention relates to a sandwich-structure flat active actuator that is symmetrical relative to the mid-plane comprising at least one piezoelectric flat layer having an active direction superpose and fixedly attached to at least one passive flat layer of fabric with rigid warp and weft oriented in two directions forming a mesh; the two directions of each layer of fabric are the same. The active direction of each piezoelectric layer is oriented along one and the same diagonal of the mesh of the layers of fabric. The invention is also aimed at a device consisting of two actuators mounted head-to-tail. The invention applies to the active torsion of structures such as, for example, a helicopter blade.

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: 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.

Abstract: A sensor comprises two identical vibrating members operating with a common working frequency and joined to each other by a mechanical decoupling device. The device comprises a frame and two connecting bridges each supporting one member. The frame comprises a succession of mass portions and thinned portions so that the frequency of one mode of structural resonance of the frame is substantially equal to the common working frequency, and each connecting bridge is disposed in a node of vibration of the frame at the common working frequency. Thus, the vibrations of the two vibrating members are decoupled from each other.

Abstract: In a nonlinear optical medium such as the gallium arsenide, two collinear incident monochromatic waves are injected to generate a monochromatic wave. The medium induces between the three waves a propagation phase-shift that has a value ? if the three waves travel a coherence length in the medium and that is compensated at the value 0 modulo 2? each time that the three waves have travelled a periodic distance in the medium. In order to significantly increase the conversion efficiency, the periodic distance between two successive bounces of total internal reflection of the waves in zig-zag is strictly less than the coherence length. The high conversion efficiency on a very short material length leads to product high-power coherent optical sources particularly with wavelengths of approximately 10 ?m.