Lubricating a metal surface of a metal part, such as a glass mould, by cold spraying a metal powder

Abstract

The present disclosure relates to a method for lubricating a metal surface (2) of a metal part that is configured to come into contact with a parison, such as a glass mould (1). This method comprises a step of cold spraying a metal powder (4) in the solid state onto the metal surface (2) so as to obtain a solid deposit (5). It also comprises a step (120) of machining the solid deposit (5) so as to obtain a lubricating coating (6). The present disclosure also relates to a metal powder, a surface treatment machine and a surface treatment facility for implementing such a method, and to a part obtained by means of such a method.

Description

[0001] DESCRIPTION

[0002] TITLE: Lubrication of a metal surface of a metal part, such as a glassware mold, by cold projection of a metal powder

[0003] TECHNICAL FIELD

[0004] This application generally concerns metal castings in the field of glassmaking, in particular cast iron, brass, bronze (and other alloys including copper and tin) or steel molds used to make glass objects such as bottles or, in general, any metal part likely to come into contact with the glass parison (or gob).

[0005] The present application relates more particularly to the lubrication of the metal surface of metal parts which comes into contact with the parison during the manufacture of glass objects. It finds a particular, but not limiting, application in the lubrication of the molding surfaces of molds in order to improve the loading and unloading of the molds during the roughing phase.

[0006] STATE OF THE ART

[0007] The manufacture of a glass object, particularly hollow glass such as a bottle, is done in several stages.

[0008] During a first stage called roughing, viscous glass is melted (at a temperature between 700 °C and 1200 °C), cast in the form of a parison, fed via a deflector and a distribution channel, into a mold, called a roughing mold. The viscous glass undergoes compression in the roughing mold and is then pierced in order to bring it into contact with the walls of the roughing mold and obtain a roughing. The roughing then has a temperature of up to 900 °C, depending on the area and thickness of the roughing.

[0009] Then, during a second stage called blowing, the blank thus formed is transferred into a finishing mold to be blown and give it its final shape. During contact between the blank and the finishing mold, a significant drop in temperature occurs as well as an elongation of the glass. The final product is obtained after this blowing stage. It then has a temperature of around 600°C.

[0010] During the roughing stage, several loading defects may appear (bone- or banana-shaped parison, parison offset, etc.). In the case of a bottle-type object, if these defects are minimal, only a few folds appear on the body of the bottle and / or on the shoulder. However, if the offset is too significant, the parison cannot penetrate to the bottom of the roughing mold. The pressing against the walls of the roughing mold will therefore be degraded, which can lead to the formation of defects at the rings (bottle neck), and therefore the rejection of the bottle. It has therefore been proposed to lubricate the molding surface of the roughing molds, i.e. the surface that comes into contact with the parison, by regularly depositing a lubricant on this surface. The lubricant generally includes a graphite-filled grease to allow the parison to penetrate into the roughing mold and facilitate the removal of the roughing.

[0011] However, this lubrication operation must be repeated very regularly to be effective, typically every twenty minutes, which reduces the productivity of the molding process. Furthermore, it is generally carried out manually by the operators: the temperature around the blank mold is very high, which creates a difficult working environment for the operators, the blank molds themselves being at a temperature of around 500 °C. In addition, fouling of the mold and the production machine can occur due to the presence of carbon residues due to the use of graphite grease. Due to the successive openings and closings of the mold to allow lubrication, the temperature of the mold is also heterogeneous, which destabilizes the molding process.Finally, since the lubrication of the molds is not controlled (and is therefore not uniform over the entire molding surface of the rough mold), localized wear by abrasion can appear and the lubricant can decompose under the effect of high temperatures.

[0012] It has also been proposed to replace lubrication with semi-complete combustion of acetylenes. However, this combustion requires a constant presence of combustible projection gas on site, which is expensive.

[0013] EXPOSED

[0014] One aim of this application is to remedy the aforementioned drawbacks.

[0015] To this end, the invention relates, according to a first aspect, to a method for lubricating a metal surface of a metal part configured to come into contact with a parison, for example a molding surface of a glassware mold comprising the following steps:

[0016] - cold projection of a metal powder in the solid state onto the metal surface so as to obtain a solid deposit, the metal powder comprising a mixture of a lubricating powder consisting of titanium dioxide and a matrix powder, the metal powder comprising between 3% and 10% by mass of lubricating powder, the remainder being matrix powder; and

[0017] - machining of the solid deposit to obtain a lubricating coating.

[0018] Some preferred but non-limiting features of the lubrication method according to the first aspect are the following, taken individually or in combination: - the matrix powder consists essentially of, by mass relative to the total mass of the metal powder;

[0019] - NiCr powder, the nickel content in the NiCr powder being between 40 and 50% by mass and the chromium content being between 50% and 60% by mass, relative to the total mass of the NiCr powder, it being understood that the sum of the components is equal to 100%; or

[0020] - NiCr powder, the nickel content in the NiCr powder being between 75 and 85% by mass and the chromium content being between 25% and 15% by mass, relative to the total mass of the NiCr powder, it being understood that the sum of the components is equal to 100%; or

[0021] - CuNiAIZn powder comprising: between 60% and 70%, preferably between 62% and 68%, of copper; between 7% and 17%, preferably between 10% and 15%, of nickel; between 5% and 15%, preferably between 8% and 12%, of aluminum; and between 5% and 15%, preferably between 8 and 12%, of zinc; it being understood that the sum of the components is equal to 100%;

[0022] - the metal powder comprises 95% NiCr powder;

[0023] - a particle size of NiCr powder is between 10 and 40 micrometers;

[0024] - a particle size of the CuNiAIZn powder is greater than or equal to 15 microns and less than or equal to 45 microns

[0025] - a particle size of the lubricating powder is between 5 and 40 micrometers;

[0026] - the metal powder is projected using a projection gas subjected to a pressure greater than thirty bars, for example between forty bars and seventy bars, for example around fifty bars;

[0027] - the metal powder is projected using a projection gas heated to a temperature greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C;

[0028] - during the projection step, a projection distance, corresponding to a distance between a nozzle for projection of the metal powder and the metal surface, is between 15 millimeters and 40 millimeters, preferably equal to approximately 20 millimeters;

[0029] - during the projection step, a displacement speed of a nozzle for projection of the metal powder during projection is between 200 millimeters per second and 1000 millimeters per second, preferably between 200 and 450 millimeters per second

[0030] - the projection step is carried out for a sufficient time to obtain a solid deposit having a thickness of between 0.3 millimeters and 3 millimeters, preferably between 0.5 millimeters and 1 millimeter; and / or

[0031] - a flow rate of supply of the metal powder during the cold projection stage is between 1 and 10 cm 3 / min, preferably between 2 and 3 cm 3 / min, for example of the order of 2.5 cm 3 / min.

[0032] According to a second aspect, there is provided a metal part having a metal surface configured to come into contact with a parison, such as a glassware mold, the metal part comprising:

[0033] - a metal surface; and

[0034] - a lubricating coating covering all or part of the metal surface and comprising a metal alloy resulting from the cold projection of a metal powder onto the metal surface in accordance with a lubrication method according to the first aspect.

[0035] Optionally, the metal surface comprises at least one of the following materials: graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, a copper and tin based alloy such as bronze, iron-carbon steel, refractory steel or stainless steel, brass.

[0036] DESCRIPTION OF FIGURES

[0037] Other characteristics, aims and advantages will emerge from the following description, which is purely illustrative and not limiting, and which must be read in conjunction with the attached drawings in which:

[0038] Figure 1 schematically illustrates an example of an installation for the lubrication of a glassware mold according to one embodiment;

[0039] Figure 2 is a flowchart illustrating steps of a method of lubricating a surface of a metal part according to one embodiment;

[0040] Figure 3 is a schematic sectional view of a metal part, here a glassware mold, comprising a lubricating coating according to one embodiment;

[0041] Figure 4 is a schematic view showing a drop of parison on the free surface of a glass mold type substrate;

[0042] Figure 5 is a curve illustrating the viscosity of the glass composing the parison drop of Figure 4 as a function of temperature.

[0043] Throughout the figures, similar elements have identical references.

[0044] DETAILED DESCRIPTION

[0045] In the following, the present disclosure will be more particularly described in the case of the lubrication of the molding surface 2 of a glassware mold 1. This is not, however, limiting, the present disclosure applying to the lubrication of any metal surface of a metal part configured to come into contact with the parison. With reference to Figure 1, the present application relates to the lubrication of all or part of the molding surface 2 of a glassware mold 1. The glassware mold 1 may in particular comprise a blank mold 1 configured to receive a drop of glass (parison) and form a blank. The molding surface 2 corresponds to the surface of the mold

[0046] 1 likely to come into contact with the parison during the molding process. The molding surface 2 may in particular comprise at least one of the following materials: graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, bronze (and other alloys comprising copper and tin), steel of the iron-carbon steel type, refractory steel or stainless steel, brass. Preferably, the glassware mold 1 is integrally formed from the same constituent material as the molding surface 2.

[0047] In order to lubricate the molding surface 2 of a glassware mold 1, it is proposed to cold-project and at a very high speed, by a projection gas 3 under high pressure transporting it, a metal powder 4 onto all or part of the molding surface 2.

[0048] Cold and high-pressure projection, known by its English name "cold spray", makes it possible to obtain a deposit density very close to the theoretical density of the solid metallic material constituting the powder, without heating the molding surface 2 during deposition, which avoids modifying the metallurgical quality of the molding surface 2 and the solid deposit 5. It also makes it possible to obtain high thicknesses of deposits (up to several millimeters) with low roughness and a material yield of more than 90%, as well as high interparticle cohesion. In addition, the implementation of this cold projection does not require a prior step of preparing the molding surface 2 or masking the mold 1 to be treated.

[0049] LUBRICATION PLANT 9

[0050] An installation 9 intended for this lubrication of all or part of the molding surface

[0051] 2 of a glassware mold 1 is shown in Figure 1. This installation 9 comprises a lubrication machine 10 and a machining station 11.

[0052] The lubrication machine 10 is configured to cold spray the metal powder 4, in solid form, onto the molding surface 2 of the mold 1. For this purpose, it comprises a spray nozzle 7, preferably made of ceramic, comprising:

[0053] - a system for heating and pressurizing a projection gas 3, typically nitrogen or helium, in a pressurization chamber 12;

[0054] - a powder dispenser 13 for supplying the metal powder 4;

[0055] - an injection system 18 for injecting the metal powder 4 into the projection gas 3 downstream of the pressurization chamber 12 so that it is not heated by the lubrication machine 10 and therefore remains in the solid state;

[0056] - a transport system 19 for transporting the metal powder 4 from the powder distributor 13 to the injection system 18 by means of a carrier gas (typically identical to the projection gas 3);

[0057] - a convergent-divergent nozzle 8 placed downstream of the injection system 18 and configured to accelerate the projection gas 3 when it transports the metal powder 4, the divergent part of the nozzle 8 forming a deposition tube 14; and

[0058] - a cooling system 15 which may comprise a conduit which surrounds the deposition tube 14 in order to cool the projection gas 3, which transports the metal powder 4, by conduction by circulating a cooling fluid around the deposition tube 14; the cooling fluid may in particular comprise distilled water at a temperature lower than the temperature of the projection gas 3, typically at a temperature between 8 and 20°C.

[0059] The lubrication machine 10 further comprises a support 17 configured to fix the glassware mold 1 relative to the projection nozzle and actuators configured to move the projection nozzle 7 relative to the molding surface 2 in the three spatial directions. These actuators can move the projection nozzle 7, the support 17 on which the mold 1 is mounted or both the projection nozzle 7 and the support 17. The actuators are configured to move the nozzle relative to the molding surface 2 at a speed of between 200 millimeters per second (mm / s) and 1000 millimeters per second (mm / s). Preferably, in order to limit premature wear of the installation, and in particular of the injection head, the scanning speed is between 200 and 450 mm / s (to within 5%).The actuators are further configured to shift the impact zone by a distance between 0.5 millimeters and 2.5 millimeters (no sweep between two adjacent cords), for example in the order of one or two millimeters (to within 10%).

[0060] The heating system is configured to heat the projection gas 3 to a temperature greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C. The projection gas 3 is furthermore pressurized in the pressurization chamber to a pressure greater than or equal to thirty-five bars, preferably between forty bars and seventy bars, for example of the order of fifty bars.

[0061] The spray nozzle 7 can be controlled by a remote control station 16, placed near the lubrication machine 10 or remotely.

[0062] The machining station 11 comprises a support configured to receive the mold 1 coated with the solid deposit 5 and a machining tool, such as a milling machine, configured to machine the solid deposit 5 and obtain the lubricating coating 6. The machining tool can be handled by an operator or mounted on the installation 8 and controlled by a remote control station, for example the same control station 16 of the projection nozzle 7.

[0063] LUBRICATION PROCESS 100

[0064] A method 100 for lubricating the molding surface 2, implemented by the lubrication installation 9, is shown in Figure 2. It comprises the following steps:

[0065] - cold projection 110 of a metal powder 4 in the solid state onto the molding surface 2 of the glassware mold 1 so as to obtain a solid deposit 5; and

[0066] - machining 120 of the solid deposit 5 so as to obtain a lubricating coating 6 (Figure 3).

[0067] The method 100 can be applied to the entire molding surface 2 of the mold 1 or to only a part of this surface 2.

[0068] During the projection step 110, a high-temperature (typically nitrogen or helium) and high-pressure projection gas 3 is used to propel the metal powder 4 at a supersonic speed (greater than 300 m / s) onto the molding surface 2 in order to create a solid deposit 5 intended to form the lubricating coating 6 by impact of the metal powder 4 on the molding surface 2, the impact force ensuring the quality of the deposit. In the present application, the deposit is said to be “solid” insofar as the grains of the metal powder 4 remain in the solid state throughout the projection and adhesion step 110 to the molding surface 2, as opposed to processes during which the temperature of the metal powder 4 exceeds its melting temperature so that all or part of the powder 4 melts at some point during the process 100.When the metal powder 4 comes into contact at high speed with the molding surface 2, it mechanically adheres to the molding surface 2 by plastic deformation with strong adhesion, which makes it possible to avoid defects linked to high temperatures such as oxidation, residual stresses, phase transformations, etc. The solid deposit 5 is then integral with the molding surface 2, that is to say that it can only be separated from the molding surface 2 by being completely or partially damaged.

[0069] The projection step 110 is said to be cold insofar as the metal powder 4 is not heated before or during deposition, other than by its contact with the projection gas 3 or the molding surface 2.

[0070] During the projection step 110, the projection gas 3 is heated and pressurized in order to ensure that the metal powder 4 is projected at a projection speed (speed of the metal powder 4 at the outlet of the nozzle 7) capable of allowing the plastic deformation of the metal powder 4 during its impact against the contact surface. It will be noted that the gas is heated and pressurized before injecting the solid powder into the gas and its projection onto the molding surface 2 in order to ensure that the metal powder 4 remains in the solid state. For this purpose, said projection speed is greater than or equal to the critical speed of the metal powder 4.This critical speed corresponds to the speed from which the attachment (adhesion) of the solid deposit 5 is possible: when the impact speed is lower than the critical speed of the material, then the particles of metal powder 4 do not deform plastically and can rebound and / or erode the molding surface 2. The critical speed depends on the nature of the material and the size of the grains of the metal powder 4. The critical speed is for example higher in the case of a metal powder 4 comprising a hard material, such as a titanium dioxide-based material (above 1250 m / s), than in the case of a metal powder 4 comprising a ductile material, such as a copper-based material (of the order of 600 m / s). An equation E1 for determining the critical speed of a material was demonstrated by T. Schmidt, F. Gartner, H. Assadi, H. Kreye, “Development of a generalized parameter window for cold spray deposition”, Acta Mater.54 (2006) 729-742; https: / / doi.Org / 10.1016 / j.actamat.2005.10.005): c. r = (E1 ) where: Or is the breaking stress of the material; p is the density of the material to be characterized;

[0071] Tj is the initial temperature of the material to be characterized;

[0072] T m is the melting temperature of the material to be characterized; c p is the specific heat;

[0073] T r is a reference temperature equal to 293 K; and

[0074] Fi and F2 are calibration coefficients used to recalibrate the calculated value to measured speed values.

[0075] The pressure applied to the projection gas 3 is therefore chosen so as to exceed the critical speed of the metal powder 4 used for the solid deposition 5. A pressure greater than or equal to thirty-five bars, preferably greater than or equal to forty bars, for example equal to fifty bars, is suitable for most metal powders which can be used in the lubrication of a glassware mold 1.

[0076] Furthermore, the temperature to which the projection gas 3 is heated is typically greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C. This heating temperature is advantageously at least 300°C below the melting temperature of the constituent of the metal powder 4 with the lowest melting temperature and for example between 300 and 700°C below this melting temperature. Where appropriate, the projection gas 3 may further be accelerated by the configuration of the projection nozzle 7 (modification of the gas passage section, for example in a convergent-divergent nozzle 8, etc.).

[0077] For a 50 / 50 nickel-chromium powder described below, the critical speed is, for example, around 574 m / s.

[0078] If necessary, the projection gas 3 may be cooled downstream of the point of injection of the metal powder 4 into the gas in order to ensure that the metal powder 4 remains solid without reducing the projection speed of the powder.

[0079] The projection step 110 is carried out so as to obtain a solid deposit 5 whose thickness is sufficient to allow machining of the solid deposit 5 and obtaining of the lubricating coating 6. This thickness of the solid deposit 5 is typically between 0.3 millimeters and 3 millimeters, preferably between 0.5 millimeters and 2.5 millimeters. The thickness of the coating 6 (after machining) can thus be between 0.1 millimeters and 1.5 millimeters.

[0080] For this purpose, the molding surface 2 is moved relative to the lubrication machine 10 during the projection step 110 in order to carry out a deposit on all or part of the molding surface 2. The projection nozzle 7 can be moved while the glassware mold 1 is fixed, or alternatively the glassware mold 1 can be moved while the projection nozzle 7 is fixed, or both the projection nozzle 7 and the glassware mold 1 are moved. The relative movement speed and the number of passes over a given surface determine the thickness of the deposit. For example, the relative displacement speed of the projection nozzle 7 and the molding surface 2 of the glassware mold 1 may be between 200 millimeters per second (mm / s) and 1000 millimeters per second (mm / s), for example of the order of 200 millimeters per second (mm / s) to 450 millimeters per second (mm / s) (to within 5%).

[0081] The flow rate of supply of the metal powder 4 by the distributor 13 is between 1 and 10 cm 3 / min, preferably between 2 and 3 cm 3 / min, for example of the order of 2.5 cm 3 / min. The metal powder 4 thus supplied is entirely transported by the carrier gas to the injection system 18, so that this supply flow rate also constitutes an injection flow rate of the metal powder 4 into the projection gas 3 by the injection system 18. For this purpose, the flow rate of carrier gas is typically between 2.0 and 6.0 cubic meters per hour (m 3 / h), for example of the order of 4.5 cubic meters per hour (m 3 / h) or 4.0 m 3 / h.

[0082] The size (width of the bead) of the solid deposit 5 is preferably between 0.5 millimeters and two millimeters, for example of the order of one millimeter (to within 10%). This size depends on the distance between the outlet of the projection nozzle 7 of the lubrication machine 10 and the molding surface 2 and on the outlet diameter of the projection nozzle 7. In order to obtain the aforementioned solid deposit size, said distance is typically between fifteen millimeters and sixty millimeters, for example of the order of twenty millimeters (to within 10%), for an outlet diameter of the projection nozzle 7 of between two and ten millimeters, for example of the order of six millimeters.

[0083] The scanning pitch (distance between the centers of two adjacent solid deposit beads 5) is between 0.5 millimeters and two millimeters, for example of the order of one millimeter (to within 10%). It is preferably substantially equal to the size of the solid deposit 5.

[0084] After machining, the porosity of the coating 6 may be between 0.2% and 15%, preferably between 0.2% and 5.0%, knowing that the lower the porosity of the coating 6, the closer the behavior (in terms of sliding of the parison) of the lubricating coating 6 is to the behavior of a graphite grease. This porosity is a function of the projection parameters used during step 110. It is evaluated in the following manner: a color image of the coating 6 is obtained with a Leica DMi8 C optical microscope using a x5 magnification and the automatic exposure parameters of the microscope; this image is then binarized using the ImageJ software (version 1.53f51), this binarization comprising the following steps: o conversion of the image into 8-bit grayscale using the ad hoc function of the software, then o conversion into black and white using the automatic thresholding function (Yen method) of the software (thresholding function defining the gray intensity establishing the threshold between the pixels converted into white and those converted into black); finally, the surface fraction of black pixels compared to the rest of the image is calculated (equation E2), this surface fraction being assimilated to the porosity rate:.

[0085] METAL POWDER 4

[0086] The metal powder 4 preferably comprises 75% by mass or more of spherical grains, relative to the total mass of the powder.

[0087] Laser particle size is measured according to ISO 13320:2019.

[0088] The diameter of the grains of the powder is advantageously between 10 and 50 pm, in particular between 12 and 45 pm, and preferably has a D50 value between 20 and 30 pm.

[0089] The melting temperature of the powder components is typically higher than the parison temperature - which can reach 1100°C - in order to avoid thermal degradation of the lubricant coating 6 during molding. Preferably, the melting temperature of the powder component having the lowest melting temperature is 300°C higher than the parison temperature.

[0090] The "packed density" is evaluated according to the basis of the NF EN ISO 3923 (2018) standard relating to "Metal powders - Determination of the apparent density after packing". Typically, a test tube with a volume of 25 cm is used. 3and a KERN SEAL balance with a maximum capacity of 6000 g and a resolution of 0.1 g. The compaction is stopped after 3000 strokes.

[0091] The "yray density" is evaluated according to the basis of the standard NF EN ISO 8130-2 (2011) relating to "Powders for coating - Determination of the density using a gas pycnometer (reference method)". A helium pycnometer (Quantachrome Upyc 1200 e) with a 10 cm cell is used. 3 The mass of the powder is measured with a balance, for example METTLER TOLEDO AB104 with a maximum capacity of 110 g and a resolution of 0.1 mg.

[0092] The tapped density of metal powder is typically between 3 and 7 g / cm 3 .

[0093] True density is typically between 6 and 10 g / cm 3, preferably with a low standard deviation, for example 0.001. Metal powders having such a true density in fact make it possible to obtain a denser solid deposit 5.

[0094] For the purposes of this disclosure, a powder is “essentially composed” of a compound A when the powder comprises at least 98% by mass, preferably at least 99% by mass of the compound A, relative to the total mass of the powder.

[0095] The metal powder 4 comprises a first powder called “matrix”, to enable its adhesion to the molding surface 2. This first matrix powder gives the coated mold improved thermomechanical and / or heat diffusion properties.

[0096] The metal powder 4 also comprises, in addition to the matrix powder, a lubricating powder, to facilitate the penetration of the parison into the glassware mold 1 and facilitate the demolding of the blank.

[0097] The metal powder 4 has a lubricating powder content of 3% to 10% by mass, typically 5% by mass, relative to the total mass of the metal powder 4.

[0098] The metal powder 4 is advantageously obtained by simply mixing the matrix powder and the lubricating powder. Those skilled in the art will be able to determine the duration, type and intensity of stirring necessary to obtain a homogeneous lubricating metal powder.

[0099] Lubricating powder

[0100] The lubricating powder may comprise or consist of a metal oxide in powder form. Preferably, the lubricating powder comprises or consists essentially of titanium oxide (denoted TiO2). The lubricating powder advantageously comprises at least 95% by mass, very advantageously at least 98% by mass of spherical grains, relative to the total weight of the lubricating powder.

[0101] The tapped density of the lubricating powder is typically between 0.8 and 1.8 g / cm 3 , especially between 1.0 and 1.5 g / cm 3 The true density of the lubricating powder is typically between 3.5 and 4.5 g / cm 3 , notably between 3.8 and 4.2 g / cm 3 .

[0102] The particle size of the lubricating powder is advantageously between 5 and 40 pm. The D50 value of the lubricating powder is typically between 15 and 20 pm.

[0103] Matrix powder comprising a NiCr alloy

[0104] According to a first embodiment, the matrix powder is essentially composed of an alloy of nickel and chromium (called nickel-chromium alloy and denoted NiCr). By essentially composed, it will be understood here that at least 98% by mass of the NiCr powder is composed of the alloy of nickel and chromium, the remainder being able to comprise at most 2% by mass of another component. Preferably, the matrix powder comprises at least 99% by mass of NiCr. The other component may for example comprise at least one of the following elements: carbon, silicon, manganera, oxygen, nitrogen. A coating comprising NiCr gives the mold thermomechanical protection. In particular, a coating comprising NiCr gives the mold better abrasion resistance, which is particularly useful in the case of molds for borosilicate glass.

[0105] The Nickel content in the NiCr alloy is advantageously between 40% and 85% by mass, preferably between 45 and 80% by mass, relative to the total mass of the NiCr alloy, the remainder being essentially made up of chromium.

[0106] For example, the nickel content in the NiCr alloy is between 40 and 50% by mass, while the chromium content is between 50% and 60% by mass, relative to the total mass of the NiCr alloy (i.e., the balance necessary to achieve essentially 100% of the NiCr alloy mass), for example, about 80% by mass of nickel and about 20% by mass of chromium (to within 1%) relative to the NiCr alloy mass. In another example, the nickel content in the NiCr alloy may be between 75 and 85% by mass, with the chromium content being between 25 and 15% by mass relative to the total mass of the NiCr alloy (i.e., the balance necessary to achieve essentially 100% of the mass of NiCr alloy), for example, about 80% by mass of nickel and about 20% by mass of chromium (to within 1%) relative to the mass of NiCr alloy.

[0107] The particle size of the NiCr matrix powder is advantageously between 10 and 40 pm. The D50 value of the NiCr powder is typically between 20 and 30 pm. The tapped density of the NiCr matrix powder is typically between 4 and 5 g / cm 3 , notably between 4.3 and 4.8 g / cm 3 The true density of NiCr matrix powder is typically between 7.5 and 8.5 g / cm 3 , notably between 7.6 and 8.0 g / cm 3 .

[0108] According to an example of implementation of this first embodiment, the metal powder 4 comprises or is essentially made up of:

[0109] - 90 to 97% by mass, for example 95% by mass, of NiCr; and

[0110] - 3 to 10% by mass, in particular 5% by mass, of titanium dioxide.

[0111] According to this example, the metal powder 4 can be obtained by mixing the NiCr powder with the titanium dioxide powder for 15 to 24 hours to obtain a homogeneous powder, for example for 17h30, then the mixture is placed in a hermetic enclosure until use. In order to improve the homogeneity of the deposition, the mixture can be placed under an inert atmosphere in the hermetic enclosure.

[0112] Matrix powder comprising a cupronickel type alloy

[0113] According to a second embodiment, the matrix powder comprises or is essentially made of an alloy of copper, nickel, aluminum and zinc, which for the sake of simplification will be called "cupronickel" in the following or CuNiAIZn. A coating comprising a so-called "cupronickel" alloy gives the mold better heat diffusion properties, which allows the glass to be cooled more homogeneously upon contact with the coated mold. Such a coating is particularly advantageous in the case of molds for soda-lime glasses.

[0114] According to this second embodiment, the matrix powder is essentially made up of a powder of an alloy comprising, by mass relative to the total mass of the alloy:

[0115] • between 60 and 70%, preferably between 62 and 68%, of copper;

[0116] • between 7 and 17%, preferably between 10 and 15%, of nickel;

[0117] • between 5 and 15%, preferably between 8 and 12%, of aluminum;

[0118] • between 5 and 15%, preferably between 8 and 12%, of zinc; and

[0119] • the possible complement preferably being essentially made up of chromium, manganese and / or iron; it being understood that the sum of the components is equal to 100%.

[0120] By essentially consisting, it will be understood here that the matrix powder comprises at least 97%, preferably at least 99%, of copper, nickel, aluminum and zinc. Typically, the other component represents at most 3% by mass, preferably at most 1%, relative to the total mass of the alloy. Preferably, the other component may comprise, by mass relative to the total mass of the alloy: • at most 1% of chromium;

[0121] • at most 1% manganese; and / or

[0122] • at most 1% iron.

[0123] By way of non-limiting example, the “cupronickel” matrix powder may comprise (relative to the total mass of the matrix powder):

[0124] • 68.1% by mass (± 0.4%) of copper;

[0125] • 15.4% by mass (± 0.1%) of nickel;

[0126] • 9.02% by mass (± 0.06%) of aluminum;

[0127] • 7.5% by mass (± 0.1%) of zinc; And

[0128] • 640 ppm (m) of oxygen, provided that the sum of the components is equal to 100%.

[0129] The tapped density of the "cupronickel" matrix powder is typically between 1 and 6 g / cm 3 , notably between 4.5 and 5.5 g / cm 3 The true density of the "cupronickel" matrix powder is typically between 4 and 9 g / cm 3 , especially between 7.5 and 9.0 g / cm 3 .

[0130] The particle size of the “cupronickel” matrix powder is advantageously between 15 and 45 pm. The D50 value of the “cupronickel” powder is typically between 20 and 30 pm.

[0131] According to an example of implementation of this second embodiment, the metal powder 4 is essentially made up of:

[0132] - 90 to 97% by mass, for example 95% by mass, of cupronickel; and

[0133] - 3 to 10% by mass, in particular 5% by mass, of titanium dioxide, it being understood that the sum of the components is equal to 100%.

[0134] According to this example, the metal powder 4 can be obtained by mixing the cupronickel powder with the titanium dioxide powder for 15 to 24 hours to obtain a homogeneous powder, for example for 17h30, then the mixture is placed in a hermetic enclosure until use. In order to improve the homogeneity of the deposition, the mixture can be placed under an inert atmosphere in the hermetic enclosure.

[0135] EXAMPLES OF LUBRICATING A GLASSWARE MOLD 1

[0136] Examples of carrying out the lubrication of a glassware mold 1 will now be described, with reference to Figure 4.

[0137] EXAMPLE 1 I - Materials and methods

[0138] Preparation of metal powder 4

[0139] Metal powder 4 is obtained by mixing a matrix powder of NiCr with a lubricating powder of TiCh, in the following proportions:

[0140] - 95% by mass of NiCr powder comprising 50% by mass of nickel and 50% by mass of chromium (i.e., in the total powder, 47.5% by mass of nickel and 47.5% by mass of chromium); and

[0141] - 5% by mass of titanium dioxide powder.

[0142] These powders are mixed for 17.5 hours to obtain a homogeneous metal 4 powder, which is placed in an airtight container until use.

[0143] The NiCr powder used consists of an alloy comprising approximately 50% by mass of Nickel and approximately 50% by mass of Chromium. It is marketed by SANDVIK OSPREY.

[0144] The melting temperature of the NiCr compound is 1345 °C.

[0145] The NiCr powder comprises at least 75% by mass, advantageously at least 80% by mass of spherical grains, relative to the total weight of the NiCr powder.

[0146] The average value of the packed density after three measurements is 4.7 g / cm 3 .

[0147] The powder test sample for true density measurement was 30.8561 g. The average true density value after five measurements was 7.71 g / cm 3 with a standard deviation of 0.001.

[0148] Three measurements were carried out to determine the parameters D10, D50 and D90 (laser granulometry). The average of these parameters is as follows:

[0149] - D10 = 14.7 pm;

[0150] - D50 = 26.1 pm; and

[0151] - D90 = 44.0 pm.

[0152] The TiC>2 powder used is marketed by Saint Gobain under the name “TiC>2 anastase nanostructured powder”.

[0153] The TiOs powder comprises at least 95% by mass, advantageously at least 98% by mass of spherical grains, relative to the total weight of the TiCh powder. The surface appearance of the grains is very smooth. At least 80% by weight of the grains have internal porosities, relative to the total weight of the TiC>2 powder.

[0154] The average value of the packed density after three measurements is 1.2 g / cm 3 .

[0155] The true density was measured under the same conditions as for the NiCr compound, with a powder sample of 7.3359 g. The average true density value after five measurements was 4.16 g / cm 3 with a standard deviation of 0.002. The laser granulometry was carried out under the same conditions as for the NiCr compound: the average of these parameters is as follows:

[0156] - D10 = 8.80 pm;

[0157] - D50 = 17.8 pm; and

[0158] - D90 = 33.9 pm.

[0159] Preparation of plates representative of the molding surface of a glassware mold

[0160] Four flat plates 22 are prepared. Each plate 22 has a free surface 21 representative of the molding surface 2 of a glass mold 1 and intended to receive a drop of glass.

[0161] The four plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.

[0162] A first of these plates 22 is untreated, that is to say that neither the lubricating coating 6 nor even a conventional lubricant such as graphite-loaded grease is applied to its free surface 21.

[0163] A second of these plates 22 has its free surface 21 coated with a conventional lubricant comprising a graphite-filled grease. This grease, of the KleenMold® brand, comprises: the following solid particles: calcium (Ca), sulfur (S), carbon (C), oxygen (O) and calcium carbonate (CaCOs), and the following binders: sulfur (S), silicon (Si) and chlorine (Cl).

[0164] A third of the plates 22 has its free surface 21 covered with a first lubricating coating 6 obtained according to the lubrication method 100 of the present disclosure, with the following parameters: Laval type ceramic projection nozzle 7 (convergent divergent) with an outlet diameter of 6 mm; projection gas 3: nitrogen; temperature and pressure of the gas in the pressurization chamber 12: 1000°C, 50 bars; cooling fluid: distilled water; distance between the outlet of the projection nozzle 7 and the impact zone on the molding surface 2: 20 mm;

[0165] - speed of movement of the projection nozzle 3: 800 mm / s; metal powder 4: consisting of nickel-chromium and titanium dioxide, as described above, at room temperature (20°C); flow rate of supply of the metal powder 4 by the distributor 13: 11.872 cm 3 / min; carrier gas flow rate: 4.5 m 3 / h; thickness of solid deposit 5: 0.5 mm; thickness of lubricating coating after machining of the solid deposit: 0.2 mm; porosity of the coating (after machining of solid deposit 5): approximately 1.3%; adhesion of lubricating coating 6 (after machining of solid deposit 5): between 35 MPa and 45 MPa.

[0166] A fourth of the plates 22 has its free surface 21 covered with a bonding underlayer, itself coated with a second lubricating coating 6 obtained according to the lubrication method 100 of the present disclosure.

[0167] The bonding undercoat is obtained by cold spraying of a powder consisting essentially of a NiCr alloy comprising approximately 80% by mass of Nickel and approximately 20% by mass of Chromium, with the following parameters: Laval type ceramic spray nozzle (convergent divergent) with an outlet diameter of 6 mm; spray gas: helium;

[0168] - temperature and pressure of the gas in the pressurization chamber 12: 750°C, 42 bars;

[0169] - cooling fluid: distilled water; distance between the outlet of the spray nozzle and the impact zone on the molding surface: 30 mm;

[0170] - projection nozzle movement speed: 800 mm / s; powder delivery rate: 8.904 cm 3 / min; carrier gas flow rate: 3 m 3 / h; thickness of solid deposit: between 250 and 350 pm.

[0171] The solid deposit 5 intended to form the second lubricating coating 6 is obtained with the following parameters: Laval type ceramic projection nozzle 7 (convergent divergent) with an outlet diameter of 6 mm; projection gas 3: nitrogen; temperature and pressure of the gas in the pressurization chamber 12: 1000°C, 50 bars;

[0172] - cooling fluid: distilled water; distance between the outlet of the projection nozzle 7 and the impact zone on the molding surface 2: 20 mm;

[0173] - speed of movement of the projection nozzle 3: 800 mm / s; metal powder 4: consisting of nickel-chromium and titanium dioxide, as described above, at room temperature (20°C); flow rate of supply of the metal powder 4 by the distributor 13: 11.872 cm 3 / min; carrier gas flow rate: 4.5 m 3 / h; thickness of solid deposit 5: 1 mm.

[0174] The solid deposit 5 was then machined so as to obtain a thickness of lubricating coating 6, including the adhesion sub-layer, equal to approximately 1 mm. The porosity of the second lubricating coating (excluding the adhesion sub-layer) was measured at approximately 7.6%.

[0175] It - Implementation

[0176] The four plates 22 of Example 1 are tested. For this purpose, each plate 22 is placed on a support, the free surface 21 of this plate 22 being oriented horizontally on the support, and a drop of glass 20a, 20b, 20c, 20d is applied to the free surface 21 of the plate 22 while the plate 22 is heated: a first drop of glass 20a is applied to the free surface 21 of the first plate 22, a second drop of glass 20b is applied to the free surface 21 of the second plate 22, a third drop of glass 20c is applied to the free surface 21 of the third plate 22, and a fourth drop of glass 20d is applied to the free surface 21 of the fourth plate 22.

[0177] The temperature of each plate 22 is measured between 440°C and 450°C during the deposition of the glass drop 20a, 20b, 20c, 20d on the plate 22.

[0178] The glass composing the drops 20a, 20b, 20c, 20d is the same for the four plates 22. It has the following composition (the contents are expressed in mass percentage):

[0179] - B2O3: 0.66%

[0180] - Na2O: 18.9%

[0181] - MgO: 3.14%

[0182] - AI2O3: 1.87%

[0183] - SiO2: 69.7%

[0184] - SO3: 0.15%

[0185] - K2O: 0.06%

[0186] - CaO: 5.24%

[0187] - TiO2: 0.025%

[0188] - Cr2O3: < 0.020%

[0189] - Fe2O3: 0.072%

[0190] - ZrO2: 0.021% - BaO: < 0.02%

[0191] - PbO: 0.014%.

[0192] For all elements except boron, the content was determined by quantitative analysis of the glass using X-ray fluorescence spectrometry (XRF). For this purpose, a first glass sample was first obtained by grinding and making molten beads that were dissolved in a flow of lithium tetraborate. The sample was then analyzed using a BRUKER S4 Pioneer sequential wavelength dispersive spectrometer.

[0193] For boron, the content was determined by plasma excitation atomic emission spectrometry. For this purpose, a second glass sample was obtained by acid solution after alkaline fusion and removal of interfering cations. The sample was then analyzed using a Varian Vista MPX plasma excitation atomic emission spectrometer.

[0194] From the element contents thus obtained, the oxide contents were deduced by calculation.

[0195] The glass making up drops 20a, 20b, 20c, 20d also has the following physical parameters: coefficient of thermal expansion (between 20°C and 300°C): 9.9x10' 6 ±0.1x10' s K' 1 ;

[0196] - glass transition temperature: 513±6°C;

[0197] - softening temperature (Littleton point): 676±4°C;

[0198] - working temperature: 967±3°C; density: 2.484±0.003 g / cm 3 .

[0199] Finally, the said glass has the viscosity curve illustrated in Figure 5. These parameters and this curve are determined by applying the ISO 7884 standard.

[0200] The pouring temperature of the glass drops (parison) 20a, 20b, 20c, 20d is measured between 1050 °C and 1200 °C during their contact with the free surface 21 of the plate 22. Its flow speed is approximately 4 m / s. The diameter of each glass drop 20a, 20b, 20c is approximately 7 mm and its mass is 0.38±0.04 g.

[0201] Ill - Results

[0202] The geometric properties of the drops 20a, 20b, 20c, 20d obtained are measured in order to determine the capacity of the lubricating coating 6 to improve sliding and / or promote the detachment of the drop 20 on the free surface 21 of the plate 22.

[0203] For this purpose, each glass drop 20a, 20b, 20c, 20d is filmed using a high acquisition frequency camera in order to determine its geometric characteristics between 0 and 3 seconds after impact (i.e. while the drop is liquid, before it solidifies) and to deduce therefrom the capacity of the lubricating coating to allow the sliding and / or detachment of the drop 20a, 20b, 20c, 20d on the free surface 21 of the plate 22.

[0204] The measurements are carried out by image processing and polynomial interpolation of the shape of the drop 20a, 20b, 20c, 20d on the four plates 22. The average measurements (obtained after measurements carried out on three hundred images and related to the initial diameter do of the drop during the fall, before impact) are as follows:

[0205] The wetting angle 0 of a drop 20a, 20b, 20c, 20d corresponds to the angle formed between the tangent to the free surface 21 of the plate 22 and the tangent to the surface of the drop 20a, 20b, 20c, 20d at the interface between the drop 20a, 20b, 20c, 20d and the free surface 21 of the plate 22. Thus, all of the measured geometric parameters show that the wetting of a drop of glass on the free surface 21, when it is coated with the lubricating coating 6 of the plate 22, is reduced in comparison with the wetting of a substantially identical drop of glass on the free surface of a conventionally lubricated (graphite grease) or untreated plate 22.

[0206] The lubricating coating 6 therefore reduces the adhesion of the parison to the molding surface 2 and facilitates its detachment and its penetration (sliding) into the glassware mold 1 and the demolding of the blank. Thus, it is possible to reduce the frequency of lubrication of the mold 1, or even to do without any new lubrication of the mold 1, without harming the lubrication performance of the mold 1. Lubrication costs can thus be reduced, and the production rate increased.

[0207] EXAMPLE 2

[0208] Five flat plates 22 are prepared. Each plate 22 has a free surface 21 representative of the molding surface 2 of a glass mold 1 and intended to receive a drop of glass.

[0209] The five plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.

[0210] Each plate 22 has its free surface 21 covered with a lubricating coating 6 obtained according to the lubrication method 100 of the present disclosure, with the following parameters:

[0211] Pressure Temperature Speed No e gas of gas of of

[0212] Plate scanning projection projection projection scanning (mm) 1)

[0213] For each of these plates, the following parameters were used: 7 ceramic Laval type projection nozzle (convergent divergent) with an outlet diameter of 6 mm; powder flow rate: 2.89 cm 3 / min; projection gas 3: nitrogen; projection gas flow rate: 4 m 3 / h ;

[0214] - cooling fluid: distilled water; metal powder 4: consisting of nickel-chromium and titanium dioxide, as described above in example 1, at room temperature (20°C); and number of passes: 10

[0215] The effectiveness of the cold spray parameters can be evaluated in particular by measuring the thickness of the deposits obtained:

[0216] Thickness

[0217] Deposit plate (mm) 0.84 0.60 0.69 0.72 1.02

[0218] Plate 5 has an optimal thickness. The deposition efficiency of plate 1 is also satisfactory.

[0219] The porosity of the coatings was assessed by making a slice of the coating.

[0220] Comparison of plates 3 and 4 shows equivalent efficiency and similar porosity by increasing the pressure and temperature parameters (40 bar - 900°C to 50 bar - 1000°C). Plate 3 was made with a scanning pitch of 2 mm and a speed of 200 mm / s while the coating of plate 1 was made with a pitch of 1 mm and a speed of 400 mm / s. As a result, reducing the pitch and increasing the projection speed allows to increase the deposited thickness and to decrease the porosity (evaluated by image analysis at 1.0% ± 0.5 for plate 1 against 2.3% ± 0.3 for plate 3).

[0221] The comparison of plates 1 and 5 demonstrates a gain in efficiency (ratio between the mass of the coating obtained and the mass of powder projected onto the plate) by increasing the temperature of the projection gas from 1000°C (plate 1) to 1100°C (plate 2). The efficiency (%DE, acronym for deposition efficiency) of plates 1 and 5 is 52% and 68% respectively.

[0222] The projection distance is optimized at 20 mm because we observe a slight reduction in the thickness deposited on plates 3 and 2 (20 mm and 35 mm).

[0223] Plate 5 leads to the thickest coating and above all a very good compactness of the coating which displays very little porosities. The quantification of the porosity rate by image analysis evaluates the porosity rate of the coating of plate 5 at 0.3% ± 0.05 and that of plate 3 at 2.3 ± 0.3.

[0224] The following table gives the porosity size indices (equivalent diameters in area) of the coatings of plates 3 and 5 calculated by image analysis. The minimum size of the porosities considered is 0.99 pm 2 . Pla

[0225] The median size (equivalent in area) of the porosity is three times smaller in the coating of plate 5 than in the coating of plate 3. Note that these porosity size values ​​are satisfactory for application to glassware molds.

[0226] The binding rate of the coating of plate 3 is evaluated by image analysis at 83.7% and that of plate 5 at 98.4% demonstrating the excellent performance of the parameterization of plate 5.

[0227] No cracks were found in all plates and cross-sections analyzed.

[0228] The coating of plate 5 is optimal in terms of thickness, porosity, yield and bonding rate. The roughness of coating 5 is equal to 7.0 pm (measured with a Mitutoty SJ210 roughness tester).

[0229] For NiCr powder, the optimized projection parameters are as follows:

[0230] EXAMPLE 3

[0231] Preparation of metal powder 4

[0232] Metal powder 4 is obtained by mixing a matrix powder of NiCr with a lubricating powder of T1O2, in the following proportions:

[0233] - 95% by mass of NiCr powder comprising 78.7% by mass of nickel (± 0.6%) and 20.10% by mass of chromium (± 0.05%) (i.e., in the total powder, 39.35% by mass of nickel and 10.1% by mass of chromium); and

[0234] - 5% by mass of titanium dioxide powder.

[0235] The NiCr powder used is Metco 43VF-NS powder marketed by SANDVIK OSPREY.

[0236] The exact composition of the powder is listed below:

[0237] These powders are mixed for 17.5 hours to obtain a homogeneous metal 4 powder, which is placed in an airtight container until use.

[0238] The melting temperature of the NiCr compound is 1345 °C.

[0239] NiCr powder comprises irregularly shaped particles.

[0240] The average value of the packed density after three measurements is 4.6 g / cm 3 .

[0241] The average true density value after five measurements was 8.30 g / cm 3 .

[0242] Three measurements were carried out to determine the parameters D10, D50 and D90 (laser granulometry). The average of these parameters is as follows:

[0243] - D10 = 11.7 pm;

[0244] - D50 = 21.6 pm; and

[0245] - D90 = 36.6 pm.

[0246] The TiCh powder is identical to that used in example 1.

[0247] Preparation of plates representative of the molding surface of a glassware mold

[0248] Seven 22-plane plates are prepared identically to Example 2, using NiCr 80 / 20 powder.

[0249] The seven plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.

[0250] Each plate 22 has its free surface 21 covered with a lubricating coating 6 obtained according to the lubrication method 100 of the present disclosure, with the following parameters:

[0251] For each of these plates, the following parameters were used: Laval type 7 ceramic projection nozzle (convergent divergent) with an outlet diameter of 6 mm; powder flow rate: 2.45 cm 3 / min; projection gas 3: nitrogen; projection gas flow rate: 4 m 3 / h ;

[0252] - cooling fluid: distilled water; metal powder 4: consisting of nickel-chromium and titanium dioxide, as described above in example 3, at room temperature (20°C); and number of passes: 10

[0253] The effectiveness of the cold spray parameters is evaluated by measuring the thickness of the deposits obtained:

[0254] Thickness

[0255] Deposit plate (mm) 1.03 0.84 0.98 0.98 1.13 0.88 1.12

[0256] The coating of plates 1, 5 and 7 has an optimal thickness. The coatings were obtained with a pitch of 1 mm and a speed of 400 mm / s. This pair of projection pitch and scanning speed parameters are therefore relevant.

[0257] Analysis of plate coatings 1, 2, 3, 4 and 7 shows that it is advantageous to use lower pressure / temperature parameters for spraying NiCr 80 / 20 powder.

[0258] The yield obtained is satisfactory for all the plates (88% for plate 5 and 65% for plate 2 for example). The yield of plate 1 is calculated at 80%. The porosity of the coatings was evaluated by making a slice of the coating. The coatings have a very good metallurgical quality, with a porosity rate between 1.5% and 4%.

[0259] The porosity of the coatings was assessed by taking a slice of the coating. The coatings of plates 1 to 6 have very good metallurgical quality, with a porosity rate between 1.5% and 3%.

[0260] The bonding rate of the coatings is higher than 95% for each plate. The coating of plate 7 has a lower bonding rate and a higher porosity rate which translate into a lower metallurgical quality: this is due to the low temperature and pressure values ​​of the projection gas (800 °C and 40 bar).

[0261] The following table gives the porosity size indices (equivalent diameters in area) of the coatings of plates 1 and 7 calculated by image analysis. The minimum size of the porosities considered is 0.99 pm 2 .

[0262] Plate D(A)io D(A)so D(A),o

[0263] (pm) (pm) (pm)

[0264] No cracks were found in all plates and cross-sections analyzed.

[0265] The coating of plate 1 is optimal in terms of thickness, porosity, yield and bonding rate. The roughness of coating 1 is equal to 6.5 pm (measured with a Mitutoty SJ210 roughness meter).

[0266] EXAMPLE 4

[0267] Preparation of metal powder 4

[0268] Metal powder 4 is obtained by mixing a cupronickel type matrix powder with a TiC>2 lubricating powder, in the following proportions:

[0269] - 95% by mass of Cupronickel powder; and

[0270] - 5% by mass of titanium dioxide powder.

[0271] The Cupronickel powder used is marketed by NANOVAL. The exact composition of the powder is listed below:

[0272] These powders are mixed for 17.5 hours to obtain a homogeneous metal 4 powder, which is placed in an airtight container until use.

[0273] The melting point of the powder is 1235 °C. Cupronickel powder consists of spherical particles, except for a few clusters that are very irregular. The grains do not have many satellites.

[0274] The average value of the packed density after three measurements is 4.6 g / cm 3 .

[0275] The average true density value after five measurements was 7.44 g / cm 3 .

[0276] Three measurements were carried out to determine the parameters D10, D50 and D90 (laser granulometry). The average of these parameters is as follows:

[0277] - D10 = 14.8 pm;

[0278] - D50 = 24.4 pm; and

[0279] - D90 = 40.0 pm.

[0280] The TiC>2 powder is identical to that used in example 1.

[0281] Preparation of plates representative of the molding surface of a glassware mold

[0282] Eight 22-plane plates are prepared identically to Example 2, using NiCr 80 / 20 powder.

[0283] The eight plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.

[0284] Each plate 22 has its free surface 21 covered with a lubricating coating 6 obtained according to the lubrication method 100 of the present disclosure, with the following parameters:

[0285] For each of these plates, the following parameters were used: Laval type 7 ceramic projection nozzle (convergent divergent) with an outlet diameter of 6 mm; powder flow rate: 2.5 cm 3 / min; projection gas 3: nitrogen; projection gas flow rate: 4 m 3 / h ;

[0286] - cooling fluid: distilled water; metal powder 4: consisting of cupronickel and titanium dioxide, as described above in example 4, at room temperature (20°C); and number of passes: 10 The effectiveness of the cold spray parameters is evaluated by measuring the thicknesses of the deposits obtained:

[0287] Thickness of the deposit plate

[0288] The coating of plates 1 to 3 is too thin, which shows that the temperature of the projection gas must be at least 800°C. The efficiency gain is also very significant when the projection temperature increases from 800°C to 900°C. The efficiency is then stable for projection temperatures greater than or equal to 900°C.

[0289] The porosity of the coatings was assessed by taking a slice of the coating. The coatings have a very good metallurgical quality, with a porosity rate between 0.3% and 2%. The porosity rate of the coating of plate 7 is, for example, 0.3%, that of plates 5 and 8 is 1.4% and 1.0% respectively.

[0290] The porosity of the coatings was assessed by taking a slice of the coating. The coatings of plates 1 to 6 have very good metallurgical quality, with a porosity rate between 1.5% and 3%.

[0291] The following table gives the porosity size indices (equivalent diameters in area) of the coatings of plates 1 and 7 calculated by image analysis. The minimum size of the porosities considered is 0.99 pm 2 .

[0292] Pla

[0293] The binding rate of plates 5 and 7 is 72% and 88% respectively, which is very good.

[0294] No cracks were found in all plates and cross-sections analyzed.

[0295] The coating of plate 7 is optimal in terms of thickness, porosity, yield and bonding rate. The roughness of coating 7 is equal to 7.6 pm (measured with a Mitutoty SJ210 roughness tester). For cupronickel powder, the optimized projection parameters are as follows:

Claims

CLAIMS 1. Method for lubricating (100) a metal surface of a metal part configured to come into contact with a parison, for example a molding surface (2) of a glassware mold (1) comprising the following steps: - cold projection (110) of a metal powder (4) in the solid state onto the metal surface (2) so as to obtain a solid deposit (5), the metal powder (5) comprising a mixture of a lubricating powder consisting of titanium dioxide and a matrix powder, the metal powder (4) comprising between 3% and 10% by mass of lubricating powder, the remainder being matrix powder; and - machining (120) of the solid deposit (5) so as to obtain a lubricating coating (6).

2. Lubrication method (100) according to claim 1, in which the matrix powder consists essentially of, by mass relative to the total mass of the metal powder (4): - NiCr powder, the nickel content in the NiCr powder being between 40 and 50% by mass and the chromium content being between 50% and 60% by mass, relative to the total mass of the NiCr powder, it being understood that the sum of the components is equal to 100%; or - NiCr powder, the nickel content in the NiCr powder being between 75 and 85% by mass and the chromium content being between 25% and 15% by mass, relative to the total mass of the NiCr powder, it being understood that the sum of the components is equal to 100%; or - CuNiAIZn powder comprising: - between 60% and 70%, preferably between 62% and 68%, of copper; - between 7% and 17%, preferably between 10% and 15%, of nickel; - between 5% and 15%, preferably between 8% and 12%, of aluminum; and - between 5% and 15%, preferably between 8 and 12%, of zinc, it being understood that the sum of the components is equal to 100%.

3. A lubrication method according to claim 2, wherein the metal powder comprises 95% NiCr powder.

4. Lubrication method (100) according to one of claims 2 and 3, in which a particle size of the NiCr powder is between 10 and 40 micrometers.

5. Lubrication method (100) according to claim 2, wherein a particle size of the CuNiAIZn powder (4) is greater than or equal to 15 microns and less than or equal to 45 microns.

6. Lubrication method according to one of claims 1 to 5, in which a particle size of the lubricating powder is between 5 and 40 micrometers.

7. Lubrication method according to one of claims 1 to 6, in which the metal powder (4) is projected using a projection gas (3) subjected to a pressure greater than thirty bars, for example between forty bars and seventy bars, for example approximately fifty bars.

8. Lubrication method (100) according to one of claims 1 to 7, in which the metal powder (4) is projected using a projection gas (3) heated to a temperature greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C.

9. Lubrication method (100) according to one of claims 1 to 8, wherein during the projection step (110), a projection distance, corresponding to a distance between a projection nozzle (7) of the metal powder (4) and the metal surface (2), is between 15 millimeters and 40 millimeters, preferably equal to approximately 20 millimeters.

10. Lubrication method (100) according to one of claims 1 to 9, wherein during the projection step (110), a speed of movement of a projection nozzle (7) of the metal powder (4) during the projection is between 200 millimeters per second (mm / s) and 1000 millimeters per second (mm / s), preferably between 200 and 450 millimeters per second (mm / s).

11. Lubrication method (100) according to one of claims 1 to 10, in which the projection step (110) is carried out for a sufficient time to obtain a solid deposit (5) having a thickness of between 0.3 millimeters and 3 millimeters, preferably between 0.5 millimeters and 1 millimeter.

12. Lubrication method (100) according to one of claims 1 to 11, in which a flow rate of supply of the metal powder (4) during the cold projection step is between 1 and 10 cm 3 / min, preferably between 2 and 3 cm 3 / min, for example of the order of 2.5 cm 3 / min.

13. A metal part (1) having a metal surface configured to come into contact with a parison, such as a glassware mold (1), the metal part comprising: - a metal surface (2); and - a lubricating coating (6) covering all or part of the metal surface (2) and comprising a metal alloy resulting from the cold projection of a metal powder (4) onto the metal surface (2) in accordance with a lubrication method (100) according to one of claims 1 to 12.

14. Metal part (1) according to claim 13, in which the metal surface (2) comprises at least one of the following materials: graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, a copper and tin-based alloy such as bronze, iron-carbon steel, refractory steel or stainless steel, brass.

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