Containers coated with MGAL2O4 spinel and corundum coating

Abstract

1. A vessel for producing an oxide powder comprising lithium, the surface of the inner wall of which is composed of the following crystalline phases, as percentages based on the total weight of the crystalline phases: - MgAl2O4 spinel: more than 25% and not more than 60%; and - MgAl2O4 spinel and crystalline phases other than corundum: less than 10%; - Corundum: replenished up to 100%, A container at least partially covered by a coating having a

Description

[Technical field]

[0001] The present invention relates to a container, the surface of whose inner wall is at least partially, preferably more than 80%, covered with a coating, and to the use of said container for producing lithium-containing oxide powders, in particular oxides of metals or oxides of some lithiated transition metals. [Background technology]

[0002] The need for lithium-ion batteries is constantly increasing. Many of them include a part, typically the cathode, made of an oxide containing lithium, in particular an oxide of a metal or of several lithiated transition metals, in particular LiFePO4 (or LPF), LiMn2O4 (or LMO), or Lithium-Nickel-Manganese-Cobalt (or Li-NMC) oxide.

[0003] The cathode is typically prepared by grinding the oxide of the metal or oxides of the lithiated transition metals into a powder.

[0004] The conventional method for producing said powders includes the production of oxides and / or mixtures of various oxide precursors, followed by a heat treatment to carry out a solid-phase synthesis of the oxides of the metal or oxides of several lithiated transition metals. During said heat treatment, the mixture is placed in a container, commonly called a "sagger". The conditions for synthesizing said powders and said mixtures, especially the lithium-containing elements, are such that the container is subjected to a specific load. Summary of the Invention [Problem to be solved by the invention]

[0005] There is a need to extend the useful life of such containers.

[0006] One object of the present invention is to at least partially meet this need. [Means for solving the problem]

[0007] According to the invention, this object is achieved by a container, the surface of the inner wall of said container being partially, preferably more than 80%, preferably over the entire inner wall, covered by a coating having the following crystallized phases, as percentages by weight based on the total weight of the crystalline phases: - MgAl2O4 spinel: more than 25% and not more than 60%; and - MgAl2O4 spinel and corundum other crystalline phases: less than 10%; and - Corundum: Fill up to 100%.

[0008] The inventors have discovered that coated containers according to the present invention exhibit relatively little degradation during use, which allows for a relatively long service life, and in particular a relatively large number of cycles, for producing metal oxide powders or oxide powders of multiple lithiated transition metals.

[0009] According to preferred but non-limiting embodiments of the present invention, which may be combined with one another where appropriate, are the following: - the coating has a spinel content, as a percentage based on the crystalline phase, of more than 30% by weight, preferably more than 35% by weight, and / or less than 55% by weight, preferably less than 50% by weight; - the container comprises more than 90% by weight, preferably more than 95% by weight, more preferably more than 99% by weight of one or more oxides, one or more carbides, one or more nitrides, one or more oxynitrides, one or more borides, and mixtures thereof; - the coating has a thickness of more than 50 μm, preferably more than 100 μm, preferably more than 200 μm, preferably more than 300 μm, and less than 2000 μm, preferably less than 1500 μm, preferably less than 1000 μm, preferably less than 800 μm; - the covered inner wall surface includes the bottom of the container and a portion of the side adjacent to the bottom; - the surface of the inner wall is covered by more than 85%, preferably by more than 90%, preferably by more than 95%; - the coating extends over substantially the entire surface of the inner wall of said container; - the container comprises more than 90% by weight, preferably more than 95% by weight, of one or more oxides; - the container contains Al2O3, MgO, ZrO2, SiO2, Y2O3, and mixtures thereof; - the container has a content of AI2O3+MgO+ZrO2+SiO2+Y2O3, as percentages of oxides, of more than 90% by weight, preferably more than 95% by weight; - the container has a content of AI2O3, expressed as a percentage of oxide, of more than 90% by weight, preferably more than 95% by weight; - the container has a content of SiO2, expressed as a percentage of oxide, of more than 90% by weight, preferably more than 95% by weight; - the container has a content of Al2O3+MgO, expressed as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight; - the container has a content of AI2O3+Y2O3, expressed as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight; - the container has a content of Al2O3+MgO+SiO2, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight; - the container has a content of Al2O3+ZrO2+SiO2, expressed as percentages of oxides, of more than 90% by weight, preferably more than 95% by weight; - the container has a content of Al2O3+ZrO2, expressed as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight; - the container has a content of Al2O3+SiO2, expressed as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight; - the container comprises, as a percentage based on the weight of the crystalline phase, more than 90% by weight, preferably more than 95% by weight, of corundum, MgAl2O4 spinel, cordierite, mullite, zirconia, optionally stabilized, periclase, and mixtures thereof; the container comprises, as a percentage of the total, more than 90% by weight, preferably more than 95% by weight, based on the weight of the crystalline phases, of corundum or mullite, or a mixture of corundum and cordierite, or a mixture of corundum and mullite, or a mixture of corundum and MgAl2O4 spinel, or a mixture of corundum and cordierite and spinel, or a mixture of corundum and zirconia, or a mixture of corundum and mullite and zirconia, or a mixture of cordierite and mullite; - the container comprises more than 90% by weight, preferably more than 95% by weight, of one or more carbides, nitrides, oxynitrides, borides, and mixtures thereof; - the container comprises more than 90% by weight, preferably more than 95% by weight, of one or more carbides, nitrides, SiAlON and mixtures thereof; - the container comprises more than 90% by weight, preferably more than 95% by weight, of silicon carbide, silicon nitride, SiAlON, and mixtures thereof; - the container comprises more than 90% by weight, preferably more than 95% by weight, of a mixture of silicon carbide and silicon nitride; - the container has a perimeter selected from a polygonal, circular or elliptical shape; - the container has a bottom and at least one side, and preferably has an average thickness of less than 20 mm and more than 2 mm; - The container has a volume greater than 0.1 litres and less than 25 litres.

[0010] The invention also relates to the use of a container coated according to the invention for producing an oxide powder containing lithium, in particular an oxide of a metal or oxides of several lithiated transition metals.

[0011] definition

[0012] "Ceramic" is understood to mean an article that is neither metallic nor organic. In the context of the present invention, carbon is considered to be a ceramic article. - "coating" is understood to mean one or more layers of material of different nature from the surface of the container. - "precursor" of a crystallized oxide is understood to mean one or more materials which, after heat treatment, at temperatures above 1100°C, preferably in air, result in said crystallized phase. For example, the corundum precursor can be a transition alumina, or boehmite, or aluminium trihydroxide, etc. - For the sake of clarity, the chemical formulas of simple oxides are used to designate the content of these oxides in the composition, for example "SiO2" or "Al2O3" are used to indicate the effective presence of these constituent oxide phases of SiO2 and Al2O3, respectively, while "SiO2" or "Al2O3" indicate the content of these simple oxides in the composition under consideration. "Corundum" is conventionally understood to mean alumina of rhombohedral crystal form. "Sialon", SiAlON, is a compound of oxynitrides of at least the elements Si, Al and N, in particular a compound conforming to one of the following formulae: -Si x Al y O u N v , where: x is equal to or greater than 0, greater than 0.05, greater than 0.1, or greater than 0.2, and equal to or less than 1, less than or equal to 0.8, or less than or equal to 0.4; - y is equal to or greater than 0, or greater than 0.1, or greater than 0.3, or greater than 0.5, and is equal to or less than 1; - u is greater than 0, or greater than 0.1, or greater than 0.2, and is less than or equal to 1, or less than or equal to 0.7; v is greater than 0, or greater than 0.1, or greater than 0.2, or greater than 0.5, or greater than 0.7, but less than or equal to 1; - x+y>0, x, y, u, and v are stoichiometric indices, normalized with respect to the highest value, which is set to 1; -Me x S 12-(m+n) Al (m+n) O n N 16-n, where 0 ≤ x ≤ 2, Me is a cation selected from lanthanides, Fe, Y, Ca, Li cations, and mixtures thereof, 0 ≤ m ≤ 12, 0 ≤ n ≤ 12, and 0 < n + m ≤ 12, and is generally referred to as "α'-SiAlON" or "SiAlON-α'". - Unless otherwise specified, all oxide contents are in terms of oxide weight percentages. The weight content of the oxide of a metal element relates to the total content of this element expressed in the most stable oxide form according to industry convention. - The sum of the oxide contents does not mean the presence of all these oxides. - "Having" or "including" should be interpreted non - restrictively to mean that elements other than the indicated elements may be present.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Container

[0014] The container is preferably ceramic.

[0015] Preferably, the container contains more than 90 wt%, preferably more than 95 wt%, preferably more than 99 wt%, preferably more than 99.5 wt% of one or more oxides, one or more carbides, one or more nitrides, one or more oxynitrides, one or more borides, and mixtures thereof.

[0016] The container preferably contains more than 90 wt%, preferably more than 95 wt%, preferably more than 99 wt%, preferably more than 99.5 wt% of: - one or more oxides, or - one or more carbides, one or more nitrides, one or more oxynitrides, borides, and mixtures thereof, preferably carbides, nitrides, oxynitrides and mixtures thereof, preferably one or more carbides, one or more nitrides, SiAlON, and mixtures thereof, preferably one or more silicon carbides, one or more silicon nitrides, and mixtures thereof. including.

[0017] In a first embodiment, the container comprises more than 90% by weight of one or more oxides, preferably more than 95% by weight, preferably more than 99% by weight, preferably more than 99.5% by weight.

[0018] Preferably, the one or more oxides are selected from or include Al2O3, MgO, ZrO2, SiO2, Y2O3, and mixtures thereof.

[0019] The container preferably has an AI2O3+MgO+ZrO2+SiO2+Y2O3 content, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight.

[0020] Preferably, the container has an Al2O3+MgO+ZrO2+SiO2 content, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight.

[0021] More preferably, the container has an AI2O3+MgO+SiO2 content, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight.

[0022] In one embodiment of the first embodiment, the container has an AI2O3 content, as percentage of oxide, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight.

[0023] In one embodiment of the first embodiment, the container has a SiO2 content, as a percentage of oxide, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight.

[0024] In one embodiment of said first embodiment, the container has an Al2O3+MgO content, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight.

[0025] In one embodiment of said first embodiment, the container has an Al2O3+Y2O3 content, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight.

[0026] In one embodiment of said first embodiment, the container has an Al2O3+MgO+SiO2 content, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight.

[0027] In one embodiment of the first embodiment, the container has an AI2O3+ZrO2+SiO2 content, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight.

[0028] In one embodiment of said first embodiment, the container has an Al2O3+ZrO2 content, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight.

[0029] In one embodiment of the first embodiment, the container has an AI2O3+SiO2 content, as percentage of oxides, of more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight.

[0030] Preferably, the container comprises, as a percentage by weight of the crystalline phase, more than 90% by weight, preferably more than 95% by weight, in total, of corundum, MgAl2O4 spinel, cordierite, mullite, zirconia, optionally stabilized, periclase, and mixtures thereof. More preferably, the container comprises, as a percentage by weight of the crystalline phase, more than 90% by weight, preferably more than 95% by weight, preferably more than 99% by weight, preferably more than 99.5% by weight, in total, of corundum, MgAl2O4 spinel, cordierite, mullite, zirconia, optionally stabilized, and mixtures thereof.

[0031] Preferably, the container is more than 90%, preferably more than 95%, as a percentage by weight of the crystalline phase, of corundum or mullite, or a mixture of corundum and cordierite, or a mixture of corundum and mullite, or a mixture of corundum and MgAlO spinel, or a mixture of corundum, cordierite and spinel, or a mixture of corundum and zirconia, or a mixture of corundum, mullite and zirconia, or a mixture of cordierite and mullite.

[0032] In a second embodiment, the container comprises more than 90%, preferably more than 95%, preferably more than 99%, preferably more than 99.5% of one or more carbides, one or more nitrides, one or more oxynitrides, one or more borides, and mixtures thereof, preferably one or more carbides, one or more nitrides, one or more oxynitrides, and mixtures thereof, preferably one or more carbides, one or more nitrides, SiAlON, and mixtures thereof.

[0033] The container preferably comprises more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight of silicon carbide, silicon nitride, SiAION, and mixtures thereof.

[0034] In one embodiment of the second embodiment above, the container comprises greater than 90% silicon carbide and the complement comprises silicon metal.

[0035] More preferably, the container comprises more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight of silicon carbide, silicon nitride, and mixtures thereof.

[0036] In one embodiment of the second embodiment above, the container comprises more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight silicon carbide.

[0037] In one embodiment of the second embodiment above, the container comprises more than 90% by weight, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight of a mixture of silicon carbide and silicon nitride, preferably the weight ratio of the amount of silicon carbide to the amount of silicon nitride is more than 1, preferably more than 2, and less than 10, preferably less than 8, preferably less than 6.

[0038] Preferably, the container contains, in total, more than 90% by weight, preferably more than 95% by weight, as percentages based on the weight of the crystalline phase, of the following: corundum, MgAl2O4 spinel, cordierite, mullite, zirconia, optionally stabilized, periclase and mixtures thereof, preferably corundum, MgAl2O4 spinel, cordierite, mullite, zirconia, optionally stabilized and mixtures thereof, preferably corundum, spinel, cordierite and mixtures thereof, or - Silicon carbide, silicon nitride and mixtures thereof.

[0039] The container can have any shape.

[0040] The perimeter of the container according to the invention may be chosen from a polygon, in particular a rectangle and a square, a circle or an oval.

[0041] Preferably, the container according to the invention has a bottom and at least one side, which preferably have an average thickness of preferably less than 20 mm, preferably less than 15 mm, or even less than 10 mm, and / or preferably more than 2 mm, preferably more than 4 mm, preferably more than 5 mm.

[0042] In one embodiment, the bottom of the container has a thickness greater than the thickness of its sides, preferably 10% greater, more preferably 20% greater, more preferably 30% greater.

[0043] In one embodiment, the bottom and sides of the container have a difference in thickness of less than 10%, preferably less than 5%. Preferably, in said embodiment, the bottom of the container has substantially the same thickness as its sides.

[0044] In one embodiment, the thickness of the wall is not constant. Preferably, the thickness of the side is greater on the bottom side of the container. Preferably, the part of the side that is in contact with the bottom of the container has a thickness that is 10% greater than the thickness of the part of the side that is located opposite the bottom of the container.

[0045] In one embodiment the container has a length, i.e. the longest length, less than 500 mm, preferably less than 400 mm and / or preferably more than 100 mm, preferably more than 200 mm, and a width, i.e. the smallest dimension measured perpendicular to the length, less than 500 mm, preferably less than 400 mm and / or preferably more than 100 mm, preferably more than 200 mm.

[0046] In one embodiment, the angle between the bottom of the container and said at least one side is equal to 90°. In one embodiment, said angle is greater than 90° and less than 100°.

[0047] In one embodiment the vessel has a diameter less than 500mm, preferably less than 400mm and / or preferably more than 100mm, preferably more than 200mm.

[0048] Preferably the container has a volume of more than 0.1 litre, preferably more than 1 litre, preferably more than 2 litres, preferably more than 3 litres, and / or preferably less than 25 litres, preferably less than 20 litres, preferably less than 15 litres.

[0049] In a preferred embodiment, the bottom and sides of the container form a monolithic assembly, in other words said bottom and sides are one piece and the connection between the bottom and the sides preferably has a radius of more than 5 mm, more preferably more than 10 mm, more preferably more than 20 mm.

[0050] In one embodiment, the container is an assembly of various parts, for example an assembly of plates, the connections between said various parts being made in particular by mortise and tenon assemblies, and / or hanging assemblies, and / or recessed type assemblies (in particular using notches or grooves), and / or ceramic pins, and / or ceramic screws, and / or ceramic rivets, and / or ceramic cotter pins.

[0051] coating

[0052] The coating has the following crystalline phases, as percentages based on crystalline phase: - MgAl2O4 spinel: more than 25% by weight and not more than 60% by weight, and - MgAl2O4 spinel and crystalline phases other than corundum: less than 10%; - Corundum: Fill up to 100%.

[0053] The crystalline phases present in a coating can conventionally be identified by X-ray diffraction on said coating.

[0054] The acquisition of the diffractograms is carried out with a D8 Endeavor type instrument from Bruker, over the angular range 2θ from 5° to 80°, in steps of 0.01°, with a counting time of 0.34 s / step. The front optic has a primary slit of 0.3°, and a Soller slit of 2.5°. The sample is rotated at a speed equal to 5 rpm using an automatic cutter. The rear optic has a 1D detector with a Soller slit of 2.5°, a nickel foil of 0.0125 mm, and an aperture of 4°.

[0055] The diffractograms are then qualitatively analyzed using EVA software and the ICDD2016 database.

[0056] Once the phases present have been identified, the diffraction patterns are quantitatively analyzed by Rietveld refinement using HighScore Plus software, according to the following strategy: - refinement of the background signal is performed using the "treatment", "determined background" function with the following options selected: "bending factor" equal to 1 and "granularity" equal to 40; - Conventionally, current ICDD files that are both specified and quantifiable are selected and therefore considered for refinement; - then an automatic refinement is performed by selecting the previously determined background signal ("use available background") and by selecting the "automatic,option phase fit-default Rietveld" mode; - Manual refinement of the "B overall" parameters is then performed simultaneously for all selected phases.

[0057] The inventors have demonstrated that such a coating makes it possible to extend the service life of the container when producing oxide powders containing lithium, in particular oxides of metals or oxides of multiple lithiated transition metals.

[0058] The inventors have also demonstrated that coatings having a MgAl2O4 spinel content of more than 60% exhibit cracking and / or spalling of the surface of the container when the temperature is increased to the working temperature, and containers having such coatings may not have an improved service life.

[0059] Coated vessels having coatings with MgAl2O4 spinel content less than 10% do not have improved service life.

[0060] The coating preferably has a spinel content of MgAl2O4, as a percentage based on the crystalline phase, of more than 30 wt.-%, preferably more than 35 wt.-%, preferably less than 55 wt.-%, preferably less than 50 wt.-%.

[0061] Preferably, the coating has a content of crystalline phases other than MgAl2O4 spinel and corundum of less than 8% by weight, preferably less than 5% by weight, based on the crystalline phases. Preferably, the coating has a content of crystalline phases other than MgAl2O4 spinel and corundum that is substantially zero.

[0062] Preferably, the coating has an amount of amorphous phase less than 10%, preferably less than 5%, preferably substantially zero.

[0063] Preferably, the coating has the following chemical composition, as percentage of oxides: MgO: more than 2.8% by weight, preferably more than 4% by weight, preferably more than 5.5% by weight, preferably more than 7% by weight, preferably more than 8.5% by weight, and preferably less than 16.9% by weight, preferably less than 15.5% by weight, preferably less than 14% by weight; and / or Al2O3: more than 73.1% by weight, preferably more than 75% by weight, preferably more than 78% by weight, preferably more than 80% by weight, preferably more than 83% by weight, and preferably less than 97% by weight, preferably less than 95% by weight, preferably less than 92% by weight, preferably less than 90%; and / or Oxides other than MgO and Al2O3: less than 10% by weight, preferably less than 8% by weight, preferably less than 6% by weight, preferably less than 5% by weight, preferably less than 3% by weight, preferably less than 1% by weight, preferably less than 0.5%.

[0064] The coating consists of more than 90% by weight of the oxide, preferably more than 95% by weight, preferably more than 98% by weight, preferably more than 99% by weight, preferably more than 99.5% by weight. Preferably, the coating consists essentially of the oxide.

[0065] The thickness of said coating is preferably more than 50 μm, preferably more than 100 μm, preferably more than 200 μm, preferably more than 300 μm, or even more than 400 μm, or even more than 500 μm, or even more than 600 μm, and / or preferably less than 2000 μm, preferably less than 1500 μm, preferably less than 1000 μm, preferably less than 800 μm.

[0066] Preferably, the surface of the inner wall that is covered includes the bottom of the container and a portion of the side that contacts said bottom, in other words the coating extends over the lower inner portion of the side of the container, the container being considered in its working position, said portion being the portion that contacts the powder during use of said container.

[0067] Preferably, more than 85%, preferably more than 90%, preferably more than 95%, preferably more than 96%, preferably more than 98%, preferably more than 99% of the surface of the inner wall of the container is covered by said coating. Preferably, the coating extends over substantially the entire surface of the inner wall of the container.

[0068] Preferably, at least a portion, preferably the entire surface, of the outer wall of the base is covered with a coating.

[0069] In one embodiment, greater than 90%, preferably greater than 95%, more preferably greater than 99% of the total surface area of ​​the container wall is covered by the coating.

[0070] The coating may be applied to at least a portion of the surface of the inner wall of the container according to any technique known to the person skilled in the art, in particular by application with a brush, by spraying, in particular by wet spraying, by vacuum impregnation, by immersion. Preferably, the coating is applied by wet spraying a suspension comprising one or more MgAl2O4 powders and one or more corundum or corundum precursor powders. Preferably, the suspension does not comprise a corundum precursor powder.

[0071] Preferably, the coating is subjected to a heat treatment prior to its use, the maximum temperature reached during said heat treatment being preferably higher than 1100°C, preferably higher than 1200°C, and preferably lower than 1500°C, preferably lower than 1400°C.

[0072] The hold time at said maximum temperature is preferably more than 0.5 hours and less than 5 hours, preferably less than 2 hours. EXAMPLES

[0073] The following non-limiting examples are given for the purpose of illustrating the present invention.

[0074] Example Manufacturing Protocol

[0075] To manufacture the example, 50x50x10mm 3 are machined onto the six faces of an N-Durance plate sold by Saint-Gobain Performance Ceramics and Refractories.

[0076] The large surface area of ​​each tile is then coated by wet spraying with the suspension.

[0077] The suspensions which make it possible to obtain the various coatings are prepared in the following manner.

[0078] A mixture M of alumina powder and aluminum hydroxide powder with a mass purity of more than 99% is obtained. Said mixture M has a median diameter D equal to 7 μm. 50 , and D equal to 51 μm 90 has.

[0079] Mixtures are then prepared according to Table 1 below, as percentages by weight. [Table 1]

[0080] To each mixture was then added 0.3% sodium silicate and 0.5% stabilizing solution, as well as alumina beads to prevent any segregation in the coating when it was applied to the tile, the proportions of sodium silicate and the stabilizing suspension being weight percentages based on the total weight of Mixture M and the spinel powder.

[0081] The solution is placed in a can and rolled for 10 minutes using a rotating jar, thereby mixing the various ingredients.

[0082] Next, 40% water and 2.5% dispersion adhesive are added to the can, in particular to achieve sufficient abrasion resistance of the coating, these proportions being weight percentages based on the total weight of Mixture M and the spinel powder.

[0083] The can is closed and rolled using a rolling jar for 8 hours, thereby obtaining a homogenous suspension.

[0084] The beads are then separated from the suspension by sieving.

[0085] The suspension is then placed in a compressed air gun and sprayed onto the large surfaces of the tiles, thereby obtaining a coating of substantially uniform thickness equal to 300 μm after the consolidation step by sintering.

[0086] The coated tiles are then dried in an oven at 70° C. for 12 hours.

[0087] Finally, the coated tiles undergo the following consolidation heat treatment in an electric furnace and in air: - heating at a rate equal to 300 ° C / h up to 1450 ° C, - maintaining at 1450°C for 1 hour; - Decreasing at a rate equal to 300 °C / h up to 500 °C and then decreasing uncontrolled.

[0088] The coated tiles thus obtained are then subjected to the deterioration resistance test described below:

[0089] The degradation resistance of lithium-nickel-manganese-cobalt (Li-NMC) oxide powder was evaluated on the above-described coated tiles according to Examples 1-4, the surface of the tile in contact with the powder being the surface bearing the coating described above.

[0090] The lithium-nickel-manganese-cobalt oxide powder used is prepared in the following manner:

[0091] Ni 0.8 Co 0.1 Mn 0.1 The (OH)2 powder is obtained by coprecipitation, with stirring and at a temperature equal to 50° C., of an aqueous solution of nickel nitrate, cobalt nitrate and manganese nitrate, determined in a stoichiometric ratio of 0.8:0.1:0.1, by adding NaOH and NH4OH.

[0092] After drying the precipitate, LiOH.H2O was added to the Ni 0.8 Co 0.1 Mn 0.1 (OH)2 molar ratio equal to 1.03 0.8 Co 0.1 Mn 0.1 Add to the (OH)2 powder and mix the mixture vigorously.

[0093] The mixture is then heat treated at 480° C. for 4 hours.

[0094] The powder obtained after the heat treatment is ground in an agate mortar. The powder obtained by grinding is the powder used in the deterioration resistance test.

[0095] For each example, 4.5 g of the powder is placed onto the central portion of the tile to be tested, taking care not to cover the peripheral surface of the tile with powder.

[0096] The tiles are then placed in an electric tube furnace, the tubes being made of alumina, and subjected to the following heat treatment cycle: - heating at a rate equal to 200 ° C / h up to 800 ° C, - maintaining at 800°C for 10 hours; - cooling at a rate equal to 200 °C / h up to 500 °C and then uncontrolled cooling down to room temperature.

[0097] Throughout the heat treatment process, oxygen circulates inside the tubes at a flow rate equal to 20 L / min.

[0098] The tile is then removed from the furnace. The powder present on the top of the tile is removed and 4.5 g of new powder is placed again on the central portion of the tile to be tested, taking care not to cover the peripheral surface of the tile with powder. The tile is then placed in an electric tube furnace (the tube is made of alumina) and subjected to a second heat treatment cycle, identical to the first.

[0099] The tiles are then removed from the oven. The powder present on top of the tiles is removed. The same protocol as described above is repeated again three times, so that each tile undergoes a total of five heat treatment cycles in the presence of the aforementioned powder.

[0100] The tiles are then removed from the oven and each tile is cut, thereby obtaining a cross-section of the central zone of said tile, which is then coated with resin and mirror-polished.

[0101] Next, each polished sample is observed using a scanning electron microscope at a magnification of 200x to 500x.

[0102] Table 2 below summarizes the results obtained. [Table 2]

[0103] A comparison of Example 1 with Examples 2-4 shows that the coatings of Examples 2-4 are still present after the degradation resistance test, unlike the coating of Example 1 which has almost completely disappeared.

[0104] However, a comparison of Examples 2-4 shows that the coating of Example 2, having an amount of spinel equal to 15%, has several cracks present on the outer surface of the coating and reaching the interface between the coating and the tile surface.

[0105] After the deterioration resistance test, the coating of Example 3, having an amount of spinel equal to 30%, shows that it has some cracks present on the outer surface of the coating and not extending to the interface between the coating and the tile surface.

[0106] The coating of Example 4, with 45% spinel content, had the best resistance and showed no cracks after the aging resistance test.

[0107] These results demonstrate the effectiveness of the container according to the present invention.

[0108] Of course, the invention is not limited to the described embodiments, which are provided as illustrative and non-limiting examples.

[0109] In particular, articles according to the present invention are not limited to any particular shape or size.

Claims

1. 1. A vessel for producing an oxide powder containing lithium, the surface of whose inner wall is formed of the following crystalline phases, as percentages based on the total weight of the crystalline phases: - MgAl ２ O ４ Spinel: more than 25% and not more than 60%; and - MgAl ２ O ４ Crystalline phases other than spinel and corundum: less than 10%; - Corundum: filled up to 100% A container at least partially, preferably more than 80%, covered by a coating having

2. 10. The container of claim 1, wherein: - the coating has a spinel content, expressed as a percentage based on the crystalline phase, of more than 30% by weight and / or less than 55% by weight, and / or - comprises more than 90% by weight of one or more oxides, one or more carbides, one or more nitrides, one or more oxynitrides, one or more borides, and mixtures thereof; and / or the thickness of said coating is greater than 50 μm and less than 2000 μm, and / or the surface of the inner wall covered by the coating includes the bottom of the container and part of the side in contact with the bottom, and / or - the surface of its inner wall is covered by said coating by more than 85%; container.

3. 3. The container of claim 1 or 2, comprising: - the coating has a spinel content, expressed as a percentage based on the crystalline phase, of more than 35% by weight and / or less than 50% by weight, and / or - comprises more than 95% by weight of one or more oxides, one or more carbides, one or more nitrides, one or more oxynitrides, one or more borides, and mixtures thereof; and / or the thickness of said coating is greater than 100 μm and less than 1500 μm, and / or - the surface of its inner wall is covered by said coating by more than 90%; container.

4. A container according to claim 1 or 2, comprising: - comprises more than 99% by weight of one or more oxides, one or more carbides, one or more nitrides, one or more oxynitrides, one or more borides, and mixtures thereof; and / or the thickness of said coating is greater than 200 μm and less than 1000 μm, and / or - the surface of its inner wall is covered by said coating by more than 95%; container.

5. A container according to claim 1 or 2, the thickness of said coating is greater than 300 μm and less than 800 μm, and / or - the coating extends over substantially the entire surface of the inner wall of the container; container.

6. 3. A container according to claim 1 or 2, comprising more than 90% by weight, preferably more than 95% by weight, of one or more oxides.

7. Al ２ O ３ , MgO, ZrO ２ , SiO ２ , Y ２ O ３ 7. The container of claim 6, comprising:

8. As a percentage of oxide, more than 90 wt. %, preferably more than 95 wt. % Al ２ O ３ + MgO + ZrO ２ +SiO ２ +Y ２ O ３ 3. The container according to claim 1 or 2, having the following content:

9. The container of claim 1 or 2, comprising: - Al, expressed as a percentage of oxide, greater than 90% by weight, preferably greater than 95% by weight ２ O ３ Content, or - more than 90% by weight, preferably more than 95% by weight, of SiO2, as a percentage of oxide ２ Content, or - Al, expressed as a percentage of oxide, greater than 90% by weight, preferably greater than 95% by weight ２ O ３ + MgO content, or - Al, expressed as a percentage of oxide, greater than 90% by weight, preferably greater than 95% by weight ２ O ３ +Y ２ O ３ Content, or - Al, expressed as a percentage of oxide, greater than 90% by weight, preferably greater than 95% by weight ２ O ３ + MgO + SiO ２ Content, or - Al, expressed as a percentage of oxide, greater than 90% by weight, preferably greater than 95% by weight ２ O ３ + ZrO ２ +SiO ２ Content, or - Al, expressed as a percentage of oxide, greater than 90% by weight, preferably greater than 95% by weight ２ O ３ + ZrO ２ Content, or - Al, expressed as a percentage of oxide, greater than 90% by weight, preferably greater than 95% by weight ２ O ３ +SiO ２ content, A container having:

10. Corundum, MgAl ２ O ４ 3. The container according to claim 1 or 2, comprising more than 90%, preferably more than 95%, of spinel, cordierite, mullite, zirconia, optionally stabilized, periclase, and mixtures thereof, in total, as a percentage based on the total weight of the crystalline phases.

11. Corundum or mullite, or a mixture of corundum and cordierite, or a mixture of corundum and mullite, or a mixture of corundum and MgAl ２ O ４ 11. The container according to claim 10, comprising a mixture of spinel, or a mixture of corundum and cordierite and spinel, or a mixture of corundum and zirconia, or a mixture of corundum and mullite and zirconia, or a mixture of cordierite and mullite, in total, as a percentage based on the total weight of the crystalline phases, more than 90%, preferably more than 95%.

12. 3. The container according to claim 1 or 2, comprising more than 90% by weight, preferably more than 95% by weight, of one or more carbides, one or more nitrides, one or more oxynitrides, borides and mixtures thereof.

13. 13. The container of claim 12, comprising more than 90% by weight, preferably more than 95% by weight, of one or more carbides, one or more nitrides, SiAlON, and mixtures thereof.

14. Container according to claim 13, comprising more than 90% by weight, preferably more than 95% by weight, in total of silicon carbide, silicon nitride, SiAlON and mixtures thereof.

15. Container according to claim 14, comprising more than 90% by weight, preferably more than 95% by weight, of a mixture of silicon carbide and silicon nitride.

16. A container according to claim 1 or 2, - has a perimeter selected from a polygon, a circle or an ellipse, and / or - has an average thickness, including a bottom and at least one side, of preferably less than 20 mm and more than 2 mm, and / or - having a volume greater than 0.1 liters and less than 25 liters, container.

17. Container according to claim 1 or 2 for producing oxide powders of a metal or oxide powders of multiple lithiated transition metals.