Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/06—Metallic material
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C16/00—Alloys based on zirconium
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/02—Coating starting from inorganic powder by application of pressure only
  • C23C24/04—Impact or kinetic deposition of particles
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C30/00—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/06—Metallic material
  • C23C4/08—Metallic material containing only metal elements
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the invention relates to a method for the anti-corrosion treatment of a workpiece by depositing a layer of zirconium and / or zirconium alloy thereon.
• This process is particularly suitable for the protection of parts intended to be brought into contact with acidic media, such as media containing nitric acid, encountered especially in the chemical industries in general and in particular in the nuclear field.
• acidic media such as media containing nitric acid
• the general field of the invention is that of corrosion.
• Corrosion means according to ISO 8044, the physicochemical interaction between a metal and its surrounding environment leading to changes in the properties of the metal and often a functional degradation of the metal, its environment or the chemical system constituted by both factors.
• corrosion refers to the alteration of an object by reaction with oxygen, the most well-known examples being the chemical alterations of metals in water, such as rust iron or the formation of verdigris on copper and its alloys, such as bronze and brass.
• the first idea may be to choose a material that does not corrode in the environment.
• a material may be, for example, stainless steel, containing in particular chromium.
• the formation of chromium oxides on the surface will thus hinder the progression of oxygen, and consequently, the deep propagation of the corrosion phenomenon.
• stainless steel has limited corrosion resistance to weakly oxidizing and acidic media. It is therefore unsuitable for strongly acidic media, such as media containing nitric acid, found in the nuclear field and in the chemical industry.
• a solution may be to control the characteristics of the environment, in particular by modifying the parameters having an influence on corrosion, such as the chemical composition (such as acidity, temperature and oxidizing power).
• the chemical composition such as acidity, temperature and oxidizing power
• this type of solution is only conceivable in a limited number of cases, especially in a closed environment.
• a last solution may consist in isolating the part from the corrosive environment, in particular by protecting the part with a layer of paint, plastic material or by introducing another part to disturb the reaction.
• the inventors have discovered, surprisingly, that by depositing on the part to be protected a thin layer of a particular metallic element and / or an alloy thereof in particular conditions, it was possible to respond effectively to the need mentioned above.
• the invention relates to a method of anti-corrosion treatment of a part comprising a step of depositing by spraying on the surface thereof a zirconium and / or zirconium alloy layer, said part being , advantageously, maintained during the deposition step, at a temperature less than 200 0 C.
• zirconium alloy is meant, conventionally, a mixture of predominantly zirconium (more than 50% by weight) and another metal element chosen, for example, from hafnium, iron, chromium, tin, nickel, niobium, copper and mixtures thereof.
• This anti-corrosion treatment process is particularly advantageous in that zirconium is an element with very good corrosion resistance properties in most aggressive aqueous media.
• the inalterability of zirconium is due to its very high affinity for oxygen and to the characteristics of the formed oxide film, this film having significant coverage and adhesion as well as high chemical stability.
• This method is simple to implement because it does not require, advantageously, subsequent processing steps after the deposition step.
• the process of the invention consists, advantageously, solely in a deposition step by projecting a zirconium and / or zirconium alloy layer on the surface of a piece, said part being advantageously maintained during the deposition step, at a temperature below 200 ° C.
• zirconium and its alloys have, in oxidizing medium of the acidic type nitric, excellent resistance to corrosion over a very wide range of concentrations and temperatures.
• the corrosion rate of the zirconium remains below 4.5 mg.dm.sup.- 1. ⁇ m / year), with a generalized corrosion morphology
• the corrosion rate remains below 18 mg.dm ⁇ d "1 (ie 100 microns / year).
• Zirconium and its alloys are therefore particularly advantageous for forming a coating for parts intended to be in contact with an aggressive aqueous medium.
• the deposited layer is zirconium (that is to say not zirconium alloy), pure zirconium being even more effective than its alloys in terms of corrosion resistance.
• This method may be intended to coat new parts or to reload corroded parts (especially in nuclear environment).
• This layer of zirconium and / or zirconium alloy may have a thickness of up to 2 mm and is advantageously free of oxide (s).
• the deposition step can be advantageously carried out by a technique selected from electric arc projection, HVOF projection, plasma projection, cold spraying.
• the deposition step is performed by the preferred technique of cold spraying.
• the step of depositing the zirconium and / or zirconium alloy layer is carried out by electric arc projection (also known in the English terminology of the "Arc Spray” method). ).
• the principle of the electric arc projection consists of sparking an electric arc between two consumable and conductive wires (in this case zirconium and / or zirconium alloy wires), which perform both a function of electrode and a filler material function to form the layer.
• the wires may be annealed wires of zirconium and / or zirconium alloy having a diameter of 1.6 mm.
• the molten metal, resulting from the melting of the consumable and conducting wires following contact with the arc, is then projected onto the part to be treated by a jet of neutral gas, such as argon.
• This embodiment is particularly suitable for producing coatings on parts intended to be subjected to an environment acid, such as a medium comprising nitric acid at 11 mol.l '1 at a temperature of 60 0 C, that the coating is intended to coat a new part or to carry out repairs on a damaged part .
• an environment acid such as a medium comprising nitric acid at 11 mol.l '1 at a temperature of 60 0 C
• the deposition step of the zirconium layer and / or zirconium alloy may be carried out by HVOF projection (acronym corresponding to "High Velocity Oxygen Fuel” also known in French as “oxygen flame projection” - high speed fuel).
• HVOF projection is a supersonic flame projection process, in which the energy required for the fusion and acceleration of the filler (here zirconium or zirconium alloy) is obtained by the combustion of a fuel in gaseous form (for example, propane, propylene, hydrogen, acetylene, natural gas) or liquid (such as kerosene) and oxygen, the fuel and the oxidant being, for example, a stoichiometric mixture. It can also be used, in addition to the aforementioned mixture, a propellant gas, preferably a neutral gas, such as argon.
• the filler product is conventionally in the form of zirconium son and / or zirconium alloy.
• the wires may be annealed wires of zirconium and / or zirconium alloy having a diameter of 1.6 mm.
• the gases burned in a combustion chamber generally flow into a nozzle, where they are accelerated to reach a supersonic speed at the nozzle outlet (for example, of the order of 700 m / s) and will contribute to the transport of zirconium. injected into the same nozzle.
• Temperatures e.g. of from 2000 to 4000 0 C
• the speeds reached by the gas jet e.g. from 1800 to 2200 m. S -1
• the deposition step of the zirconium layer and / or zirconium alloy can be performed by plasma spraying.
• the principle of plasma spraying is to project melted particles which, under the effect of temperature and speed, crash on the surface of the workpiece, where they mechanically cling.
• an electric arc is initiated by high frequency and maintained by a low voltage power source in a plasma gas flow.
• the plasma gas may be argon, nitrogen, mixtures thereof, optionally in the presence of hydrogen and / or helium. Under the effect of high temperatures, the gas molecules dissociate and then ionize it and obtain a highly conductive medium allowing the maintenance of an electric arc between the cathode and the anode with a difference in temperature. potential.
• the plasmagene gas also subject to considerable expansion (up to more than 100 times its initial volume), contributes to the constriction of the arc, which has as its effect of raising the temperature and forcing the gas out of the anode in the form of plasma.
• the plasma consisting of dissociated and partially ionized gases emerges from the nozzle-shaped anode at high speed (which may be of the order of Mach 1) and at high temperature (for example, from 10,000 K to 14,000 K ).
• the zirconium and / or zirconium alloy in powder form is injected into the plasma in the nozzle anode or more generally at the outlet thereof. Accelerated and melted, the particles are projected on the surface of the part to be coated with a very high kinetic energy, which allows an optimal attachment.
• This embodiment is particularly suitable for producing coatings on new parts intended to be subjected to an acidic environment, such as a medium comprising nitric acid at 11 mol.l -1 at a temperature of 60 ° C. .
• the deposition step of the zirconium and / or zirconium alloy layer can be performed by cold spraying (corresponding to the English terminology "CoId Spray”), which is the preferred technique. of the invention.
• the principle of the cold projection is to accelerate a gas (such as nitrogen, helium, argon), heated to a temperature ranging from 100 to 700 0 C, at supersonic speeds in a nozzle of the type "Laval" then the powder of material to be sprayed (here, the zirconium powder and / or zirconium alloy) is introduced into the high pressure part (between 10 and 40 bar) of the nozzle and is projected to " unmelted state "towards the surface of the part to be coated at a speed of between 600 and 1200 m / s. In contact with the workpiece, the particles undergo a plastic deformation and form on impact a dense and adherent coating.
• a gas such as nitrogen, helium, argon
• This embodiment lies in the non-melting of the particles, therefore in a very low risk of oxidation and possible integration in a hostile environment.
• This embodiment is particularly suitable for producing coatings on parts intended to be subjected to an acid environment, such as a nitric acid medium at 11 mol.l -1 at a temperature of 60 ° C. or 14 mol.l -1 at 120 ° C., that this coating is intended to be in place on a new part or to carry out repairs on a part having suffered damages.
• an acid environment such as a nitric acid medium at 11 mol.l -1 at a temperature of 60 ° C. or 14 mol.l -1 at 120 ° C.
• the deposition step is also advantageously carried out in a neutral gas atmosphere (such as argon), so as to reduce in particular the risks of pyrophoricity of the zirconium powder.
• a neutral gas atmosphere such as argon
• the deposition step can be performed in the presence of a cooling system or propulsion under a neutral gas.
• the part to be coated in particular except for laser deposition, is maintained, during the deposition step, at a temperature below 200 ° C., in order to ensure good cohesion with the substrate.
• the metal parts that can be treated by the process of the invention may be steel parts, zirconium or zirconium alloy parts, iron parts or iron-based alloys.
• the metal parts when made of steel, may be ferritic, martensitic, and in particular austenitic precipitation-hardened ferritic-martensitic steel or austenitic-ferritic steel parts, corresponding to shading described in standard NF EN 10088 (such as steel X 2 CN 18 10, X 2 CND 17 13, X 2 CN 25 20 or X 2 CNS 18 15).
• the metal parts that can be treated by the process of the invention may also be zirconium or zirconium-based alloy parts.
• the purpose of the process may be, in addition to protecting the piece of corrosion, reloading said zirconium piece, for example, to carry out repairs on said damaged piece.
• This treatment method finds its application for the parts subjected to a corrosive environment, such as those used in equipment intended for the stages of the spent fuel treatment process, or more generally such as those used in the chemical industries using acids.
• oxidants such as nitric acid, sulfuric acid.
• This example illustrates the deposition of a zirconium layer by electric arc projection on a piece of 304L stainless steel or zirconium.
• the device used for this projection is a TAFA 9000 Arc Spray. It consists of a generator module with integrated wire coils and a gun. The gun is embedded on a robot allowing a better homogeneity of the recovery of the different passes.
• the propellant used is argon.
• the gun is equipped with an "Arc Jet" device, which makes it possible to increase the particle velocity, and to better sheath the particles in an argon atmosphere up to the substrate part.
• a stripping of the piece to be treated is made by impact with abrasive (white corundum) and the piece thus stripped is then blown in the air then degreased to
• the temperature of the room is less than 200 0 C during projection.
• the projection conditions are grouped in the following Table I:
• argon as a propellant and coolant provided a homogeneous, dense deposit with a low oxide content and an adhesion of about 11 MPa.
• the hardness of the deposit is about 200 Hv and is comparable to that of solid zirconium (190 Hv).
• the corrosion tests by immersion in a nitric acid solution of 11 moles / liter at a temperature of 60 ° C. for 800 hours did not show any degradation of the previously deposited layer.
• the change in mass is less than 2 mg / dm 2 .
• This example illustrates the deposition of a zirconium layer by HVOF projection on a piece of zirconium or 304L steel.
• the apparatus used for this projection is a HV WIRE System model 2000.
• the projection gun is mounted on a motorized linear slide whose speed can be adjusted, the offsets between each pass being done manually.
• the wire is brought to the level of the gun by a conventional device ("pulled-pushed"), which allows to vary the speed of the wire, and therefore to know the amount of material consumed.
• Thread speed 0, 01 m / s
• Flow rate 0, 67 g / s
• the corrosion tests by immersion in a nitric acid solution of 11 moles / liter at a temperature of 60 ° C. for 800 hours did not show any degradation of the previously deposited layer.
• the mass variation is less than 2 mg / dm 2 .
• This example illustrates the deposition of a zirconium layer by plasma spraying on a piece of 304L stainless steel or zirconium.
• the apparatus used is a conventional torch (F4 from Metco) in an 18 m chamber, which is placed in a controlled atmosphere (argon).
• a 6-axis robot is integrated in the cabin allowing the realization of pieces of complex shapes.
• the advantage of making deposits with this type of installation is the use of an atmosphere under argon, which will limit the oxidation of zirconium.
• Stripping of the workpiece is carried out by impact with an abrasive (white corundum, having a particle size of 700 microns) under a pressure of 4.5 bar and with an angle of 45 °, in order to minimize the incrustations in the substrate.
• an abrasive white corundum, having a particle size of 700 microns
• the chamber is pre-pumped several times before the projection, and an additional cooler (FENWICK slotted cooler) was added at the torch outlet in addition to the two EMANI nozzles, which avoids the combination of residual oxygen with the molten powder during the projection. This system also reduces the temperature of the room.
• the projection conditions are grouped in the following Table III.
• the deposit obtained is homogeneous, dense, free of oxide, of millimeter thickness and without cracking between the layer and the part.
• the adhesion is between 31 and 43 MPa.
• the hardness of the layer is identical to that of solid zirconium (190 Hv).
• the corrosion tests by immersion in a nitric acid solution of 11 moles / liter at a temperature of 60 ° C. for 800 hours did not show any appreciable degradation of the layer.
• the mass variation is less than 2 mg / dm 2 .
• This example illustrates the deposition of a layer of zirconium by cold spraying (so-called "CoId Spray” projection) on a piece of 304 L stainless steel or zirconium.
• the apparatus used consists of a projection booth, a robot, a pistol, a generator, a powder distributor and a gas heater.
• the projection conditions are grouped in the following Table IV.
• the deposits are homogeneous, dense and do not contain oxides.
• the hardness of the deposited layer is approximately 350 Hv, this value being greater than that of solid zirconium. This comes from the process, since the elaboration of the layer is done by stacking successive sub-layers and the high speed of the particles causes a phenomenon of hardening, which increases the hardness of the layer. This is of interest in that the layer can provide both an anti-corrosion function and an anti-wear function.
• the corrosion tests by immersion in a nitric acid solution of 11 moles / liter at a temperature of 60 ° C. for 800 hours did not show any degradation of the deposited layer.
• Another test of 168 hours in a nitric acid solution of 14 mol / liter at a temperature of 120 ° C. has also not shown degradation of the deposited layer.
• the mass variation is less than 3 mg / dm 2 .

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Coating By Spraying Or Casting (AREA)
• Other Surface Treatments For Metallic Materials (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)

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• 2007
  • 2007-08-31 FR FR0757292A patent/FR2920440B1/fr not_active Expired - Fee Related
• 2008
  • 2008-08-29 US US12/675,043 patent/US20110097504A1/en not_active Abandoned
  • 2008-08-29 JP JP2010522385A patent/JP2010537058A/ja active Pending
  • 2008-08-29 WO PCT/EP2008/061373 patent/WO2009027497A2/fr not_active Ceased
  • 2008-08-29 EP EP08803371A patent/EP2183403A2/de not_active Withdrawn
  • 2008-08-29 CN CN200880104229A patent/CN101784690A/zh active Pending
  • 2008-08-29 RU RU2010105956/02A patent/RU2489512C2/ru not_active IP Right Cessation

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