Method for manufacturing a ceramic article

Abstract

The present invention relates to a method for manufacturing a ceramic article, which method comprises the steps of (Step 1) providing at least one ceramic structure obtained by a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity of at least 35.00 % and (Step 2) providing at least one slurry S1 comprising solid particles [solid particles A, herein after] and at least one liquid phase, wherein said solid particles A have a d50 particle size value equal or more than 1.00 µm and less than 30.00 µm and (Step 3) at least one dipping of at least part of the ceramic structure in the slurry S1 thereby infiltrating at least partly the open pores of the ceramic structure with the solid particles A [infiltrated ceramic structure, herein after].

Description

[0001] " Method for manufacturing a ceramic article "

[0002] The present invention relates to a method for manufacturing a ceramic article. The present invention further relates to a ceramic article, to the use of the ceramic article in a ceramic foundry filter for molten metal filtration and to the use of the ceramic article in a wear-resistant part for high-abrasion applications.

[0003] BACKGROUND OF THE INVENTION

[0004] Ceramic articles obtained by a binder jetting 3D ceramic printer are typically used in a wide range of applications in which their performance in terms of hot strength, high resistance and durability are exploited.

[0005] Typically, in metallurgical processes, foundry filters for molten metal filtration such as ceramic filters for filtering molten metal prior to casting, are used. Filters for filtering molten metal, must be able to physically withstand high temperatures. For example, in steelmaking processes, a filter must be able to physically withstand temperatures greater than 1400°C.

[0006] Known ceramic filters used in foundries for filtering steel are made from a monolithic porous ceramic foam structure, wherein the ceramic material consists of zirconia (ZrO2 - zirconium dioxide). This conventional zirconia-based ceramic foam structure is generally produced by coating a reticulated polyurethane foam (RPF) with a slurry containing zirconia. However, these conventional zirconia-based ceramic foam filters are prone to deformation or even cracking due to shrinkage that occurs during the firing process.

[0007] For example, GB 2599112 A discloses a foundry filter for filtering molten metal. In this document, the filter comprises a porous ceramic filter structure, such as a ceramic filter structure obtained by 3D ceramic printer. The ceramic structure comprises a plurality of through holes and is impregnated with a ceramic material. By carefully configuring the size and number of through holes, this filter provides the advantages of enabling a relatively constant flow rate of molten metal through the filter while preventing the filter from being blocked by inclusions / slag present in the molten metal. However, this document is silent regarding the infiltration of molten metal in the porosity of the filter structure.

[0008] Another example of an application of a ceramic structure is in a wear-resistant part used in high-abrasion applications. For example, WO 2023 / 200625 A1 discloses a reinforced wear member comprising a steel body and a ceramic core embedded in said body. The ceramic core in the steel body enables to reinforce the wear member which makes it suitable to be used in earth-engaging applications. The ceramic core may not be porous. Alternatively, the ceramic core may be formed as an open cell, porous, ceramic matrix that allows molten steel to flow into, around, and through the porous matrix, around the fibrils defining the pores of the matrix. When molten steel flows into the pores of the ceramic matrix, the ceramic core is suitably embedded in the steel body and the mechanical resistance of the wear member is improved. Unfortunately, when molten metal infiltrates into the pores of the ceramic structure, damage occurs due to cracking of the ceramic structure.

[0009] The use of high-performance ceramic articles as filtration medium for molten metal provides significant and measurable sustainability benefits. The ceramic foam filters process eliminates the need for a polyurethane (PUR) foam burnout stage, thus avoiding the release of harmful gases associated with burning off the polymer pattern, making it a more environmentally friendly option. By effectively removing inclusions and impurities from molten metal, high-performance ceramic articles greatly reduce casting defects, which in turn minimizes scrap generation and the energy-intensive rework typically associated with defective parts. Cleaner metal flow also improves downstream processing efficiency, decreasing machining time, consumable use as their high capacity and stable flow rate mean that fewer or smaller filters can be used, and overall waste. As a result, the user of filtration medium based on high-performance ceramic articles achieve higher yields, more stable production and higher-quality cast components. Together, these effects contribute to lower energy consumption, reduced emissions, and more efficient use of raw molten metal, highlighting high-performance ceramic-based filters as a key enabler of sustainable and economically resilient casting operation.

[0010] In view of the above, there is a continuous need for an improved method for manufacturing a ceramic article wherein said method is easy to implement and provides a ceramic article having several different shapes whilst also keeping its high structural strength / integrity. Said method thus provides a ceramic article having not only improved performance characteristics in terms of hot strength, mechanical resistance and overall durability, but also provide a sustainable solution. SUMMARY OF THE INVENTION

[0011] The inventors have surprisingly found that the method for manufacturing a ceramic article according to the present invention fulfils the above-mentioned need and overcomes the above-mentioned disadvantages.

[0012] In an aspect of the present invention, there is provided a method for manufacturing a ceramic article, wherein the method comprises the steps of:

[0013] Step 1 : providing at least one ceramic structure obtained by using a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity of at least 35.00 %;

[0014] Step 2: providing at least one slurry Si comprising solid particles [solid particles A, hereinafter] and at least one liquid phase, wherein said solid particles A have a dso particle size value equal or more than 1 .00 pm and less than 30.00 pm;

[0015] Step 3: performing at least one dipping of at least a part of the ceramic structure in the slurry Si thereby infiltrating at least part of the open pores of the ceramic structure with the solid particles A [infiltrated ceramic structure, hereinafter],

[0016] A ceramic article obtained according to the method of the present invention is another aspect of the present invention.

[0017] Use of the ceramic article of the present invention in a ceramic foundry filterfor molten metal filtration is another aspect of the invention.

[0018] Use of the ceramic article of the present invention in a wear-resistant part is another aspect of the invention.

[0019] DETAILED DESCRIPTION

[0020] The term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a method comprising the steps A and B” should not be limited to the method consisting only of steps A and B. It means that with respect to the present invention, the only relevant steps of the method are A and B. Accordingly, the terms “comprising” and “including” encompass the more restrictive terms “consisting essentially of” and “consisting of”. As used herein, the terms "optional" or "optionally" means that a subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0021] Unless otherwise mentioned or indicated, it is to be understood that within the context of the present invention, the temperature is the room temperature. Within the context of the present invention, the expression “room temperature”, is intended to denote a temperature ranging from -5 °C to 50 °C preferably ranging from 10 and 30 °C.

[0022] Within the context of the present invention, unless otherwise mentioned, the expression “particle size” is intended to refer to the average diameter of the particles. The particle size is measured by mechanical sieving according to EN ISO 1927-3 (2013) standard or by laser diffraction analysis.

[0023] Within the context of the present invention, the expression “dxof y pm” is intended to denote that a percentage (x%) by weight of particles has a particle size equal to or less than y pm. In other words, the expression “dxof y pm” refers to a particle size distribution (PSD). In general, the particle size distribution can be measured by methods known in the art. Preferably, the particle size distribution of the particles is measured by mechanical sieving according to EN ISO 1927-3 (2013) standard or by laser diffraction analysis. More preferably, the particle size distribution of the particles is measured by laser diffraction analysis.

[0024] Within the context of the present invention, the expression “open porosity”, is intended to refer to the volume percentage of the open pores. The open porosity thus excludes closed pores, which are part of the closed porosity.

[0025] It goes without saying that, according to the present invention, the pores are not comparable to the holes which may be present in the general shape of the ceramic structure or the ceramic article. For example, when the ceramic structure I ceramic article has a shape suitable for use as ceramic filter or as a wear-resistant part, generally it comprises a plurality of holes having an average diameter higher than 1 mm. For example, a ceramic filter may have holes having an average diameter ranging from 3 mm to 10 mm.

[0026] In general, the open porosity can be measured by methods known in the art, for example by optical methods, computed tomography method, imbibition method, water saturation method, water evaporation method, water displacement method, mercury intrusion porosimetry, gas expansion method or thermoporosimetry and cryoporometry. Unless otherwise stated, in the context of the present invention the method used to measure the open porosity is a water displacement method using Archimedes, according to the standard ASTM C20 (2022) “Standard Test Methods for Apparent Porosity, Water Absorption, Apparent Specific Gravity, and Bulk Density of Burned Refractory Brick and Shapes by Boiling Water”.

[0027] Within the context of the present invention, the expression “apparent density”, also called bulk density, is intended to refer to the mass of the particles of the material divided by the bulk volume. Bulk volume is defined as the total volume the particles occupy, including the particles' own volume, inter-particle void volume, and the particles' internal pore volume.

[0028] In general, the apparent density can be measured by methods known in the art. Unless otherwise stated, in the context of the present invention the method used to measure the apparent density is according to the standard ASTM C20 (2022) “Standard Test Methods for Apparent Porosity, Water Absorption, Apparent Specific Gravity, and Bulk Density of Burned Refractory Brick and Shapes by Boiling Water”.

[0029] Within the context of the present invention, the viscosity is measured at 20 °C at a shear rate of 10 s-1using an Anton Paar Modular compact Rheometer (MCR302).

[0030] As mentioned, according to the present invention, the method for manufacturing a ceramic article comprises Step 1 of providing at least one ceramic structure obtained by using a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity of at least 35.00 %.

[0031] It goes without saying that the ceramic article may take any shape. In general, ceramic articles are used when their high refractory qualities (e.g. the ability to withstand temperatures in excess of 1 ,650 °C) as well as high structural strength / integrity are required. Non-limiting examples of ceramic articles notably include, ceramic filters, such as ceramic foundry filters for filtering molten metal, and wear-resistant parts. Wearresistant parts are for example used in high abrasion applications, in other words, applications where abrasive materials, such as rock, sand and ore, are handled. Nonlimiting examples of applications in which wear-resistant parts are used notably include excavating, loading, dozing, grading, milling and grinding.

[0032] Ceramic structure

[0033] Within the context of the present invention, the expression “at least one ceramic structure” is intended to denote one or more ceramic structure. The ceramic structure is obtained by using a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder. In general, binder jetting 3D ceramic printing techniques known in the art can be used for obtaining the ceramic structure. Typically, binder jetting is a form of additive manufacturing, also called powderbed 3D printing. The binder jetting process is based on inkjet technology. Similar to an inkjet printer, the ceramic structure is printed, via dropping of the binder onto the ceramic compound. The binder bonds the ceramic compound to produce the ceramic structure. The ceramic compound is constantly replenished and contacted with the binder and the ceramic structure is printed layer by layer. The ceramic structure is thus typically built up from bottom to top. It goes without saying that the shape of the ceramic structure is preferably chosen according to the application of the final ceramic article, as detailed above.

[0034] Within the context of the present invention, the expression “at least one ceramic compound” is intended to denote one or more ceramic compound.

[0035] In general, a ceramic compound refers to an inorganic, non-metallic solid material that is typically composed of metal and non-metal elements bonded together by strong ionic or covalent bonds. These compounds may have a crystalline or partially crystalline structure. Generally, ceramic compounds are characterized by their hardness, high melting point, chemical resistance, and electrical insulating properties.

[0036] In general, ceramic compounds are known to the skilled person in the art and the nature of such ceramic compounds may be chosen according to their desired application.

[0037] It is further understood that the ceramic compound, as detailed above, may be commercially available, or may be chemically synthesized from commercially available starting materials according to any methods known to the skilled person in the art.

[0038] In general, a ceramic compound may be synthetically prepared by a variety of methods known in the art or can be of natural origin.

[0039] Non-limiting examples of ceramic compounds include oxides, nitrides, carbides, silicates, or mixtures thereof. Non-limiting examples of oxides notably include aluminum oxide (alumina), zirconium oxide (zirconia), silicon oxide, cerium oxide, titanium oxide, magnesium oxide and mixtures thereof.

[0040] Non-limiting examples of carbides notably include silicon carbide, tungsten carbide and mixture thereof. Non-limiting example of silicates notably include zirconium silicate, aluminum silicate and mixtures thereof. Preferably, the ceramic compound is selected among aluminum oxide, zirconium oxide, zirconium silicate, aluminum silicate, silicon oxide, silicon carbide, cerium oxide, titanium oxide, titanium carbide, magnesium oxide, tungsten carbide and mixtures of two or more thereof.

[0041] More preferably, the ceramic compound is selected from aluminum oxide, zirconium oxide, cerium oxide and mixtures thereof.

[0042] Even more preferably, the ceramic compound is a mixture of zirconium oxide and cerium oxide.

[0043] A non-limiting example of a ceramic compound being a mixture of zirconium oxide and cerium oxide notably include CeraBeads®.

[0044] Advantageously, the ceramic compound may comprise less than 3.00 wt.%, preferably less than 2.00 wt.%, more preferably less than 1.00 wt.% impurities, relative to the total weight of the ceramic compound.

[0045] Preferably, the ceramic compound is a powder. Within the context of the present invention, the term “powder” is intended to refer to any solid in a powder, granular, fragmented or equivalent state.

[0046] Advantageously, the ceramic compound consists of solid particles [solid particles B, hereinafter] having a particle size value equal to or more than 10.00 pm.

[0047] Advantageously, the particle size value of the solid particles B is equal to or more than 20.00 pm, more preferably equal to or more than 30.00 pm, more preferably equal to or more than 40.00 pm, even more preferably equal or more than 53.00 pm. It is further understood that the upper limit of the particle size value of the solid particles B is advantageously equal to or less than 500.00 pm, preferably equal to or less than 450.00 pm, more preferably equal to or less than 400.00 pm, more preferably equal to or less than 350.00 pm, more preferably equal to or less than 300.00 pm.

[0048] In an embodiment of the method of the present invention, the particle size value of the solid particles B, as detailed above, is ranging from 10.00 pm to 500.00 pm, preferably from 20.00 pm to 450.00 pm, more preferably from 30.00 pm to 400.00 pm, more preferably from 40.00 pm to 350.00 pm, even more preferably from 53.00 pm to 300.00 pm.

[0049] Advantageously, the solid particles B have a d particle size value equal to or more than 53.00 pm, preferably equal to or more than 57.00 pm, more preferably equal to or more than 60.00 pm, more preferably equal to or more than 63.00 pm, more preferably equal to or more than 67.00 pm, even more preferably equal or more than 70.00 pm. It is further understood that the upper limit of the dw particle size value of the solid particles B is advantageously equal to or less than 106.00 pm, preferably equal to or less than 100.00 pm, more preferably equal to or less than 95.00 pm, more preferably equal to or less than 90.00 pm, more preferably equal to or less than 85.00 pm, even more preferably equal to or less than 80.00 pm.

[0050] In an embodiment of method of the present invention, the dw particle size value of the solid particles B, as detailed above, is ranging from 53.00 pm to 106.00 pm, preferably from 57.00 pm to 100.00 pm, more preferably from 60.00 pm to 95.00 pm, more preferably from 63.00 pm to 90.00 pm, more preferably from 67.00 pm to 85.00 pm, even more preferably from 70.00 pm to 80.00 pm.

[0051] According to the present invention, the solid particles B have a dso particle size value equal to or more than 75.00 pm, preferably equal to or more than 80.00 pm, more preferably equal to or more than 85.00 pm, more preferably equal to or more than 90.00 pm, more preferably equal to or more than 95.00 pm, even more preferably equal or more than 100.00 pm. It is further understood that the upper limit of the dso particle size value of the solid particles B is advantageously equal to or less than 150.00 pm, preferably equal to or less than 140.00 pm, more preferably equal to or less than 130.00 pm, more preferably equal to or less than 120.00 pm, more preferably equal to or less than 115.00 pm, even more preferably equal to or less than 110.00 pm.

[0052] In an embodiment of the method of the present invention, the dso particle size value of the solid particles B, as detailed above, is ranging from 75.00 pm to 150.00 pm, preferably from 80.00 pm to 140.00 pm, more preferably from 85.00 pm to 130.00 pm, more preferably from 90.00 pm to 120.00 pm, more preferably from 95.00 pm to 115.00 pm, even more preferably from 100.00 pm to 110.00 pm.

[0053] According to the present invention, the solid particles B have a d?o particle size value equal to or more than 106.00 pm, preferably equal to or more than 110.00 pm, more preferably equal to or more than 115.00 pm, more preferably equal to or more than 120.00 pm, more preferably equal to or more than 125.00 pm, more preferably equal to or more than 130.00 pm, more preferably equal to or more than 135.00 pm, more preferably equal to or more than 140.00 pm, even more preferably equal to or more than 145.00 pm. It is further understood that the upper limit of the d?o particle size value of the solid particles B is advantageously equal to or less than 212.00 pm, preferably equal to or less than 200.00 pm, more preferably equal to or less than 190.00 pm, more preferably equal to or less than 180.00 pm, more preferably equal to or less than 175.00 pm, more preferably equal to or less than 170.00 pm, more preferably equal to or less than 165.00 pm, more preferably equal to or less than 160.00 pm, even more preferably equal to or less than 155.00 pm.

[0054] In an embodiment of the method of the present invention, the d?o particle size value of the solid particles B, as detailed above, is ranging from 106.00 pm to 212.00 pm, preferably from 110.00 pm to 200.00 pm, more preferably from 115.00 pm to 190.00 pm, more preferably from 120.00 pm to 180.00 pm, more preferably from 125.00 pm to 175.00 pm, more preferably from 130.00 pm to 170.00 pm, more preferably from 135.00 pm to 165.00 pm, more preferably from 140.00 pm to 160.00 pm, even more preferably from 145.00 pm to 155.00 pm.

[0055] According to the present invention, the solid particles B have a d9o particle size value equal to or more than 150.00 pm, preferably equal to or more than 160.00 pm, more preferably equal to or more than 170.00 pm, more preferably equal to or more than 175.00 pm, more preferably equal to or more than 180.00 pm, more preferably equal to or more than 185.00 pm, more preferably equal to or more than 190.00 pm, more preferably equal to or more than 195.00 pm, more preferably equal to or more than 200.00 pm, even more preferably equal or more than 205.00 pm. It is further understood that the upper limit of the d9o particle size value of the solid particles B is advantageously equal to or less than 300.00 pm, preferably equal to or less than 290.00 pm, more preferably equal to or less than 280.00 pm, more preferably equal to or less than 270.00 pm, more preferably equal to or less than 260.00 pm, more preferably equal to or less than 250.00 pm, more preferably equal to or less than 240.00 pm, more preferably equal to or less than 230.00 pm, more preferably equal to or less than 220.00 pm, even more preferably equal to or less than 215.00 pm.

[0056] In an embodiment of the method of the present invention, the dgo particle size value of the solid particles B, as detailed above, is ranging from 150.00 pm to 300.00 pm, preferably from 160.00 pm to 290.00 pm, more preferably from 170.00 pm to 280.00 pm, more preferably from 175.00 pm to 270.00 pm, more preferably from 180.00 pm to 260.00 pm, more preferably from 185.00 pm to 250.00 pm, more preferably from 190.00 pm to 240.00 pm, more preferably from 195.00 pm to 230.00 pm, more preferably from 200.00 pm to 220.00 pm, even more preferably from 205.00 pm to 215.00 pm.

[0057] It goes without saying that solid particles B may have a variety of shapes. For example, the solid particles B of the invention may be spherical, plate-shaped, tabular and mixtures thereof. When aluminum oxide is used in the solid particles B, aluminum oxide is preferably selected from the group consisting of spherical alumina, plate-shaped alumina, tabular alumina and mixtures thereof. Preferably, aluminum oxide is a tabular alumina.

[0058] Advantageously, the ceramic compound is a pre-sintered ceramic compound.

[0059] Within the context of the present invention, “pre-sintered” is intended to denote that the ceramic compound is subjected to a pre-sintering step before use. In general, presintering is a thermal treatment during which the ceramic compound is fired at a temperature below the melting point of the ceramic compound. During the pre-sintering step, the particles of the ceramic compound may form bonds and the contact points between particles increase thereby improving the particle to particle cohesion (grain to grain cohesion) which improves the mechanical properties of the pre-sintered ceramic compound. Advantageously, the skilled person in the art is able to determine the presintering temperature according to the nature of the ceramic compound since the presintering temperature does not have to reach the melting point of the ceramic compound.

[0060] In general, pre-sintering of the ceramic compound is carried out at a temperature equal to or more than 1400 °C, preferably equal to or more than 1450 °C, more preferably equal to or more than 1500 °C, even more preferably equal or more than 1550 °C. It is further understood that the upper limit of the temperature for pre-sintering the ceramic compound is advantageously equal to or less than 1800 °C, preferably equal to or less than 1750 °C, more preferably equal to or less than 1700 °C, even more preferably equal to or less than 1650 °C.

[0061] In an embodiment of the method of the present invention, the temperature for presintering the ceramic compound, as detailed above, ranges from 1400 °C to 1800 °C, preferably from 1450 °C to 1750 °C, more preferably from 1500 °C to 1700 °C, even more preferably from 1550 °C to 1650 °C.

[0062] Within the context of the present invention, the expression “at least one binder” is intended to denote one or more binder.

[0063] In general, binders are known to the skilled person in the art and their nature may be chosen according to their application.

[0064] It is further understood that the binder, as detailed above, may be commercially available, or may be chemically synthesized from commercially available starting materials according to any methods known to the skilled person in the art.

[0065] In general, a binder may be synthetically prepared by a variety of methods known in the art or can be of natural origin. Suitable binders may be organic or inorganic binders. For example, inorganic binders notably comprise ceramic binders. In general, inorganic binders are known to the skilled person in the art and may be chosen according to the intended application.

[0066] Non-limiting examples of inorganic binders notably comprise silicate, phosphate, aluminate, phosphoric acid, alumina gel and mixtures thereof. For example, an inorganic binder may comprise aluminum phosphate.

[0067] In one embodiment of the invention, the binder is an organic binder. Organic binders are known to the skilled person in the art and may be chosen according to the intended application.

[0068] Advantageously, when the binder is an organic binder, the organic binder comprises a resin selected from the group consisting of furane resins, phenolic resins, and mixtures thereof. Preferably, the organic binder comprises a furane resin.

[0069] As previously mentioned, the ceramic structure has an open porosity of at least 35.00 %.

[0070] Advantageously, the ceramic structure has an open porosity equal to or more than 36.00 %, more preferably equal to or more than 37.00 %, more preferably equal to or more than 38.00 %, more preferably equal to or more than 39.00 %, more preferably equal to or more than 40.00 %, more preferably equal to or more than 41.00 %, even more preferably equal or more than 42.00 %. It is further understood that the upper limit of the open porosity of the ceramic structure is advantageously equal to or less than 90.00 %, preferably equal to or less than 85.00 %, more preferably equal to or less than 80.00 %, more preferably equal to or less than 75.00 %, more preferably equal to or less than 70.00 %, more preferably equal to or less than 65.00 %, more preferably equal to or less than 60.00 %, even more preferably equal to or less than 53.00 %.

[0071] In an embodiment of the method of the present invention, the open porosity of the ceramic structure, as detailed above, is ranging from 35.00 % to 90.00 %, preferably from

[0072] 36.00 % to 85.00 %, more preferably from 37.00 % to 80.00 %, more preferably from

[0073] 38.00 % to 75.00 %, more preferably from 39.00 % to 70.00 %, more preferably from

[0074] 40.00 % to 65.00 %, more preferably from 41.00 % to 60.00 %, even more preferably from 42.00 % to 53.00 %.

[0075] As detailed above, the expression “open porosity” refers to the volume percentage of open pores of the ceramic structure. Generally, the size of the open pores of the ceramic structure is less than 1 .0 mm. Advantageously, the ceramic structure has an apparent density equal to or less than 1 .85 g / cm3, preferably equal to or less than 1 .80 g / cm3, more preferably equal to or less than 1 .75 g / cm3, more preferably equal to or less than 1 .70 g / cm3, more preferably equal to or less than 1.65 g / cm3, more preferably equal to or less than 1.60 g / cm3, more preferably equal to or less than 1 .55 g / cm3, even more preferably equal to or less than 1.52 g / cm3. It is further understood that the lower limit of the apparent density of the ceramic structure is advantageously equal to or more than 1.10 g / cm3, preferably equal to or more than 1.15 g / cm3, more preferably equal to or more than 1.20 g / cm3, more preferably equal to or more than 1 .25 g / cm3, more preferably equal to or more than 1 .30 g / cm3, more preferably equal to or more than 1.35 g / cm3, more preferably equal to or more than 1 .40 g / cm3, even more preferably equal or more than 1 .42 g / cm3.

[0076] In an embodiment of the method of the present invention, the apparent density of the ceramic structure, as detailed above, ranges from 1.10 g / cm3to 1.85 g / cm3, preferably from 1.15 g / cm3to 1.80 g / cm3, more preferably from 1.20 g / cm3to 1.75 g / cm3, more preferably from 1 .25 g / cm3to 1 .70 g / cm3, more preferably from 1 .30 g / cm3to 1 .65 g / cm3, more preferably from 1 .35 g / cm3to 1 .60 g / cm3, more preferably from 1 .40 g / cm3to 1 .55 g / cm3, even more preferably from 1 .42 g / cm3to 1 .52 g / cm3.

[0077] The method according to the present invention comprises Step 2 of providing at least one slurry Si comprising solid particles [solid particles A, hereinafter] and at least one liquid phase, wherein said solid particles A have a dso particle size value equal or more than 1 .00 pm and less than 30.00 pm.

[0078] Slurry

[0079] Within the context of the present invention, the expression “at least one slurry Si” is intended to denote one or more than one slurry Si.

[0080] The slurry Si comprises solid particles [solid particles A, hereinafter]. It goes without saying that any shape of solid particles A can be used according to the present invention. The shape of the solid particles A of the invention may be spherical, plateshaped, tabular and mixtures thereof.

[0081] In general, the nature of the solid particles A may be chosen by the skilled person in the art according to the intended application. According to the present invention, the solid particles A may be chosen for improving the performance characteristics of the ceramic article in terms of hot strength, high resistance and durability. In general, the skilled person in the art will be able to suitably select the appropriate solid particles A in order to improve the performance characteristics of the ceramic article in terms of hot strength, high resistance and durability.

[0082] In particular, the solid particles A may be made of an inorganic material, preferably a refractory material.

[0083] Advantageously, the solid particles A are selected from the group consisting of aluminium oxide, zirconium oxide, zirconium silicate, aluminium silicate, silicon carbide, cerium oxide, titanium oxide, magnesium oxide and mixtures of two or more thereof. Preferably, the solid particles A are selected from the group consisting of aluminium oxide, zirconium oxide, aluminium silicate, titanium oxide, magnesium oxide and mixtures of two or more thereof.

[0084] Advantageously, the solid particles A may comprise less than 3.00 wt.%, preferably less than 2.00 wt.%, more preferably less than 1 .00 wt.% of impurities, relative to the total weight of the solid particles A.

[0085] Advantageously, the solid particles A have a dso particle size value equal to or less than 25.00 pm, more preferably equal to or less than 20.00 pm, more preferably equal to or less than 17.00 pm, more preferably equal to or less than 14.00 pm, even more preferably equal to or less than 11.00 pm. It is further understood that the lower limit of the dso particle size value of the solid particles A is equal or more than 1 .00 pm.

[0086] In an embodiment of the method of the present invention, the dso particle size value of the solid particles A, as detailed above, is ranging from 1.00 pm to 30.00 pm, preferably from 1 .00 pm to 25.00 pm, more preferably from 1 .00 pm to 20.00 pm, more preferably from 1.00 pm to 17.00 pm, more preferably from 1.00 pm to 14.00 pm, even more preferably from 1 .00 pm to 11 .00 pm.

[0087] Advantageously, when the solid particles A are alumina, preferably reactive alumina, the dso particle size value ranges from 1 .0 pm to 6 pm, more preferably from 1 .2 pm to 5.0 pm, even more preferably from 1 .5 to 4 pm.

[0088] Advantageously, when the solid particles A are tabular alumina, the dso particle size value ranges from 1 pm to 20 pm, preferably from 1 .5 pm to 18 pm, more preferably from 2.0 pm to 15.0 pm, more preferably from 3.0 pm to 15.0 pm, even more preferably from 5.0 to 12.0 pm, most preferably from 7.0 to 12.0 pm.

[0089] Advantageously, the slurry Si has a content of solid particles A [solid content, herein after] equal to or more than 35.00 wt.%, preferably equal to or more than 40.00 wt.%, more preferably equal to or more than 45.00 wt.%, even more preferably equal or more than 50.00 wt.%, relative to the total weight of the slurry Si. It is further understood that the upper limit of the content of solid particles A in the slurry Si is advantageously equal to or less than 95.00 wt.%, preferably equal to or less than 90.00 wt.%, more preferably equal to or less than 85.00 wt.%, even more preferably equal to or less than 80.00 wt.%, more preferably equal to or less than 70.00 wt.%, most preferably equal to or less than 60.00wt.%, relative to the total weight of the slurry Si.

[0090] In an embodiment of the method of the present invention, the content of solid particles A in the slurry Si , as detailed above, is ranging from 35.00 wt.% to 95.00 wt.%, preferably from 40.00 wt.% to 90.00 wt.%, more preferably from 45.00 wt.% to 85.00 wt.%, more preferably from 50.00 wt.% to 80.00 wt.%, more preferably from 50.00 wt.% to 70.00 wt.%, most preferably from 50.00 wt.% to 60.00 wt.%, relative to the total weight of the slurry Si.

[0091] As mentioned, the slurry Si comprises at least one liquid phase.

[0092] Within the context of the present invention, the expression “at least one liquid phase” is intended to denote one or more than one liquid phase.

[0093] In general, the nature of the liquid phase may be chosen by the skilled person in the art according to its intended purpose.

[0094] Advantageously, the liquid phase of the slurry Si is a solvent selected from the group consisting of water, ethanol, isopropanol, acetone, mono-propylene glycol and mixtures thereof.

[0095] The slurry Si may further comprise at least one additive for improving the viscosity of the slurry Si. In general, the nature of the at least one additive in the slurry Si may be chosen by the skilled person in the art according to its purpose. Preferably the at least one additive in the slurry Si is a thickener, a defoamer, a dispersing agent, a wetting agent or mixtures thereof. Preferably the additive in the slurry Si is an organic additive. For example, the thickener in the slurry Si may be xanthan gum. For example, the dispersing agent in the slurry Si may be a composition comprising carboxylic acid, such as Dolapix CE 64 ®. For example, the defoamer in the slurry Si may be an aqueous emulsion of vegetable oils, polyethers and non-ionic emulsifiers, such as Agitan DF 6686 W®.

[0096] Advantageously, the content of the additive in the slurry Si , as detailed above, is equal to or more than 1 .00 wt.%, preferably equal to or more than 2.00 wt.%, preferably equal to or more than 3.00 wt.%, relative to the total weight of the slurry Si. It is further understood that the upper limit of the additive in the slurry Si is advantageously equal to or less than 15.00 wt.%, preferably equal to or less than 10.00 wt.%, more preferably equal to or less than 8.00 wt.%, even more preferably equal to or less than 6.00 wt.%, relative to the total weight of the slurry Si.

[0097] In an embodiment of the method of the present invention, the content of the additive in the slurry Si is ranging from 1.00 wt.% to 15.00 wt.%, preferably from 2.00 wt.% to 10.00 wt.%, preferably from 3.00 wt.% to 8.00 wt.%, preferably from 3.00 wt.% to 6.00 wt.%, relative to the total weight of the slurry Si.

[0098] Advantageously, the slurry Si has a viscosity equal to or more than 70.00 mPa.s, preferably equal to or more than 80.00 mPa.s, preferably equal to or more than 90.00 mPa.s, more preferably equal to or more than 100.00 mPa.s, even more preferably equal to or more than 110.00 mPa.s, most preferably equal to or more than 120.00 mPa.s. It is further understood that the upper limit of the viscosity of the slurry Si is equal to or less than 200.00 mPa.s.

[0099] The slurry Si may be prepared by a process comprising a mixing of the various components as comprised in the slurry Si, as detailed above. Furthermore, it is understood that any order of mixing of the various components as comprised in the slurry Si, as detailed above, is acceptable.

[0100] Mixing, as detailed above, may be carried out by using a variety of mixing means known in the art. Non-limiting examples of such mixing means are for example bubbling or mechanical mixing such as traditional mixers and blenders, high intensity mixers and electric stirrers.

[0101] It is understood that the skilled person in the art will carry out said mixing according to general practice such as notably using optimal times, weights, volumes and batch quantities. The mixing may be performed at room temperature.

[0102] Dipping

[0103] The method of the present invention comprises a Step 3 of at least one dipping of at least part of the ceramic structure in the slurry Si , thereby infiltrating at least partly the open porosity of the ceramic structure with the solid particles A [infiltrated ceramic structure, herein after].

[0104] In other words, the ceramic structure or at least part of the ceramic structure, as detailed above, is dipped in the slurry Si , as detailed above, thereby infiltrating at least partly the open pores of the ceramic structure with the solid particles A, as detailed above.

[0105] Within the context of the present invention, the expression “at least one dipping” is intended to denote one or more than one dipping. In general, it is understood that any step of dipping known by the skilled person can be used for dipping the ceramic structure with the aim of infiltrating at least partly the open porosity of the ceramic structure with the solid particles A. It is understood that the skilled person in the art will carry out said dipping according to general practice such as using optimal times, weights, volumes and batch quantities.

[0106] The inventors have surprisingly found that by dipping the ceramic structure, as detailed above, in the slurry Si, as detailed above, the resulting infiltrated ceramic structure has an improved hot strength and is less prone to crack propagation. Without being bound to this theory, the inventors believe that when the solid particles A infiltrate the open porosity of the ceramic structure, the infiltrated ceramic structure has a higher density and a lower porosity.

[0107] Depending on the nature and the form of the ceramic structure, the dipping step (Step 3) can be carried out in different ways. For example, the ceramic structure can at least be partly or completely immersed in the slurry Si, preferably, the ceramic structure is completely immersed in the slurry Si.

[0108] Dipping time may be selected to achieve desired infiltration goals. Preferably, the dipping time is equal to or less than 120 s, preferably equal to or less than 90 s, more preferably equal to or less than 60 s, even more preferably equal to or less than 40 s, most preferably equal to or less than 30 s.

[0109] Preferably, prior to and / or during the dipping step (Step 3), the slurry Si is agitated with the aim to improve the dispersion of the solid particles A in the slurry Si. In general, the agitation can be carried out by using bubbling or mechanical mixing such as traditional mixers and blenders, high intensity mixers and electric stirrers, wherein said mixers, blenders and stirrers can be equipped with at least one dispersion disk.

[0110] The dipping step (Step 3) may be performed at room temperature.

[0111] The method according to the present invention can comprise one or more than one dipping step (i.e. , Step 3 can be repeated one or more times). The method according to the present invention may thus comprise at least two dipping steps, or at least three dipping steps or least four dipping steps or at least five dipping steps or at least six dipping steps. In general, the skilled person in the art will be able to select the appropriate number of dipping steps to improve the performance characteristics of the ceramic structure in terms of hot strength, high resistance and durability. It is further understood that the upper limit of dipping steps (Step 3) is not critical. However, five dipping steps, or six dipping steps, or seven dipping steps, or eight dipping steps, or nine dipping steps, or ten dipping steps are particularly preferred.

[0112] According to an embodiment of the invention, the expression “one or more dipping steps” refers to two dipping steps, or to three dipping steps, or to four dipping steps, or to five dipping steps.

[0113] It is further understood that all definitions and preferences, as described above, equally apply for the further dipping steps. It is also understood that all definitions and preferences, as described above, may vary from one dipping step to another. By way of example, the solid particles A, as detailed above, the liquid phase, as detailed above, and the dipping conditions, as detailed above, may vary from one dipping step to another. For example, at least part of the ceramic structure may be subjected to a first dipping step in a slurry Si comprising alumina as solid particles A and water as liquid phase thereby infiltrating at least partly the open porosity of the ceramic structure with alumina as solid particles A and then be further subjected to a second dipping step in a slurry Si comprising alumina and zirconia as solid particles A and water as liquid phase thereby further infiltrating at least partly the open porosity of the ceramic structure with alumina and zirconia as solid particles A.

[0114] Advantageously, the infiltrated ceramic structure has an open porosity equal to or more than 5.00 %, preferably equal to or more than 7.00 %, more preferably equal to or more than 9.00 %, more preferably equal to or more than 11 .00 %, more preferably equal to or more than 13.00 %, more preferably equal to or more than 15.00 %, more preferably equal to or more than 17.00 %, even more preferably equal or more than 19.00 %. It is further understood that the upper limit of the open porosity of the infiltrated ceramic structure is advantageously equal to or less than 41 .00 %, preferably equal to or less than 39.00 %, more preferably equal to or less than 37.00 %, more preferably equal to or less than 35.00 %, more preferably equal to or less than 33.00 %, more preferably equal to or less than 31 .00 %, more preferably equal to or less than 29.00 %, even more preferably equal to or less than 27.00 %.

[0115] In an embodiment of the process of the present invention, the open porosity of the infiltrated ceramic structure, as detailed above, is ranging from 5.00 % to 41.00 %, preferably from 7.00 % to 39.00 %, more preferably from 9.00 % to 37.00 %, more preferably from 11.00 % to 35.00 %, more preferably from 13.00 % to 33.00 %, more preferably from 15.00 % to 31.00 %, more preferably from 17.00 % to 29.00 %, even more preferably from 19.00 % to 27.00 %. Advantageously, the infiltrated ceramic structure has an apparent density equal to or more than 1 .90 g / cm3, preferably equal to or more than 1 .95 g / cm3, more preferably equal to or more than 2.00 g / cm3, more preferably equal to or more than 2.05 g / cm3, more preferably equal to or more than 2.10 g / cm3, more preferably equal to or more than 2.15 g / cm3, more preferably equal to or more than 2.20 g / cm3, even more preferably equal or more than 2.23 g / cm3. It is further understood that the upper limit of the apparent density of the infiltrated ceramic structure is advantageously equal to or less than 2.70 g / cm3, preferably equal to or less than 2.65 g / cm3, more preferably equal to or less than 2.60 g / cm3, more preferably equal to or less than 2.55 g / cm3, more preferably equal to or less than 2.50 g / cm3, more preferably equal to or less than 2.45 g / cm3, more preferably equal to or less than 2.40 g / cm3, even more preferably equal to or less than 2.37 g / cm3.

[0116] In an embodiment of the present invention, the apparent density of the infiltrated ceramic structure, as detailed above, is ranging from 1 .90 g / cm3to 2.70 g / cm3, preferably from 1.95 g / cm3to 2.65 g / cm3, more preferably from 2.00 g / cm3to 2.60 g / cm3, more preferably from 2.05 g / cm3to 2.55 g / cm3, more preferably from 2.10 g / cm3to 2.50 g / cm3, more preferably from 2.15 g / cm3to 2.45 g / cm3, more preferably from 2.20 g / cm3to 2.40 g / cm3, even more preferably from 2.23 g / cm3to 2.37 g / cm3.

[0117] Advantageously, the infiltrated ceramic structure has a weight gain equal to or higher than 20.00 %, preferably equal to or higher than 30.00 %, more preferably equal to or higher than 40.00 %, more preferably equal to or higher than 50.00 %. It is further understood that the upper limit of the weight gain of the infiltrated ceramic structure is equal to or less than 95.00 %, preferably equal to or less than 90.00 %, preferably equal to or less than 80.00 %.

[0118] In an embodiment of the present invention, the weight gain of the infiltrated ceramic structure, is ranging from 20.00 % to 95.00 %, preferably from 30.00 % to 90.00 %, preferably from 40.00 % to 80.00 %, or from 50.00 % to 80.00 %.

[0119] Within the context of the present invention, the expression “weight gain”, is intended to refer to the difference in the weight of the ceramic structure before the dipping step and the weight of the infiltrated ceramic structure after the dipping step. In general, the expression “weight gain” refers to an increase in weight.

[0120] In general, the weight gain can be measured by methods known in the art. Unless otherwise stated, in the context of the present invention the method used to measure the weight gain is a weighting method. Preferably, the weight gain of an object is the difference between the initial weight of this object measured before the dipping step and the final weight of the object measured after the dipping step, expressed in %.

[0121] The method according to the present invention may further comprise, after Step 3, a step of drying the infiltrated ceramic structure at a temperature of at least 90 °C.

[0122] Drying may be carried out by using a variety of drying means known in the art. Nonlimiting examples of such drying means are for example conventional drying means used in the refractory industry such as a hot air dryer. In general, it is understood that any step of drying known by the skilled person can be used for drying the infiltrated ceramic structure with the aim of removing the liquid phase from the infiltrated ceramic structure.

[0123] Advantageously, the drying of the infiltrated ceramic structure is carried out at a temperature equal to or more than 100 °C, more preferably equal to or more than 110 °C, even more preferably equal or more than 115 °C. It is further understood that the upper limit of the temperature for the drying of the infiltrated ceramic structure is advantageously equal to or less than 150 °C, preferably equal to or less than 140 °C, more preferably equal to or less than 130 °C, even more preferably equal to or less than 125 °C.

[0124] In an embodiment of the present invention, the temperature for drying the infiltrated ceramic structure, as detailed above, ranges preferably from 90 °C to 150 °C, preferably from 100 °C to 140 °C, more preferably from 110 °C to 130 °C, even more preferably from 115 °C to 125 °C.

[0125] Advantageously, when the method of the present invention comprises more than one dipping step, a drying step, as detailed above, is performed between each dipping step.

[0126] Coating

[0127] The method according to the present invention may further comprise a step of coating at least part of the surface of the infiltrated ceramic structure with the slurry Si , as detailed above. It is understood that all definitions and preferences, as described above, for the slurry Si equally apply for the coating step.

[0128] It is also understood that all definitions and preferences, as described above, for the slurry Si may vary from the dipping step to the coating step. Preferably, the step of coating is a step of coating completely the surface of the infiltrated ceramic structure with the slurry Si , as detailed above.

[0129] Thus, according to one embodiment of the present invention, the method according to the present invention comprises, after Step 3, a step of coating at least part of the surface of the infiltrated ceramic structure with the slurry Si comprising solid particles A, as detailed above.

[0130] Alternatively, the method according to the present invention may further comprise a step of coating at least part of the surface of the infiltrated ceramic structure with at least one slurry which is different from the at least one slurry used in the dipping step 3 as detailed above [herein after, Seating], wherein the slurry Seating comprises solid particles [solid particles C, hereinafter] and at least one liquid phase, wherein said solid particles C have a dso particle size value of between 0.05 pm and 30.0 pm.

[0131] The solid particles C of the slurry Seating may be of any shape known to the skilled person in the art, such as, for example, spherical, plate-shaped, tabular, and mixtures thereof.

[0132] In general, the nature of the solid particles C of the slurry Seating may be chosen by the skilled in the art according to the intended application. According to this embodiment, the solid particles C of the slurry Seating may be chosen for improving the performance characteristics of the infiltrated ceramic structure in terms of hot strength, high resistance and durability. Furthermore, the nature of the solid particles C of the slurry Seating may be chosen in order to provide improved resistance of the infiltrated ceramic structure against degradation by molten metal.

[0133] In particular, the solid particles C of the slurry Seating may be made of an inorganic material, preferably a refractory material.

[0134] Advantageously, the solid particles C of the slurry Seating are selected from the group consisting of aluminium oxide, zirconium oxide, zirconium silicate, aluminium silicate, silicon carbide, cerium oxide, titanium oxide, magnesium oxide and mixtures of two or more thereof. Preferably, the solid particles C of the slurry Seating are selected from the group consisting of aluminium oxide, zirconium oxide, aluminium silicate, titanium oxide, magnesium oxide and mixtures of two or more thereof. More preferably, the solid particles C of the slurry Seating are selected from the group consisting of aluminum oxide, zirconium oxide, and mixture thereof.

[0135] Advantageously, the solid particles C of the slurry Seating may comprise less than 3.00 wt.%, preferably less than 2.00 wt.%, more preferably less than 1.00 wt.% of impurities, relative to the total weight of the solid particles C.

[0136] Advantageously, the solid particles C of the slurry Seating have a dso particle size value equal to or less than 25.00 pm, more preferably equal to or less than 20.00 pm, more preferably equal to or less than 17.00 pm, more preferably equal to or less than 14.00 pm, even more preferably equal to or less than 11 .00 pm. It is further understood that the lower limit of the dso particle size value of the solid particles C of the slurry Seating is advantageously equal to or more than 0.05 pm, preferably equal to or more than 0.10 pm, more preferably equal to or more than 0.25 pm, more preferably equal to or more than 0.50 pm, more preferably equal to or more than 0.75 pm, even more preferably equal or more than 1 .00 pm.

[0137] In an embodiment of the method of the present invention, the dso particle size value of the solid particles C of the slurry Seating, as detailed above, is ranging from 0.05 pm to 30.00 pm, preferably from 0.10 pm to 25.00 pm, more preferably from 0.25 pm to 20.00 pm, more preferably from 0.50 pm to 17.00 pm, more preferably from 0.75 pm to 14.00 pm, even more preferably from 1 .00 pm to 11 .00 pm.

[0138] Advantageously, when the solid particles C of the slurry Seating are zirconia, the dso particle size value ranges from 0.1 pm to 10.0 pm, preferably from 0.2 pm to 7 pm, more preferably from 0.3 pm to 6 pm, more preferably from 0.4 pm to 5.0 pm, even more preferably from 0.5 to 4.0 pm, most preferably from 0.6 pm to 2.0 pm.

[0139] Advantageously, when the solid particles C of the slurry Seating are alumina, preferably reactive alumina, the dso particle size value ranges from 0.5 pm to 10 pm, preferably from 0.7 pm to 7 pm, more preferably from 1.0 pm to 6 pm, more preferably from 1 .2 pm to 5.0 pm, even more preferably from 1 .5 to 4 pm.

[0140] Advantageously, when the solid particles C of the slurry Seating are tabular alumina, the dso particle size value ranges from 1 pm to 20 pm, preferably from 1.5 pm to 18 pm, more preferably from 2.0 pm to 15.0 pm, more preferably from 3.0 pm to 15.0 pm, even more preferably from 5.0 to 12.0 pm, most preferably from 7.0 to 12.0 pm.

[0141] Advantageously, the slurry Seating has a content of solid particles C [solid content, herein after] equal to or more than 35.00 wt.%, preferably equal to or more than 40.00 wt.%, more preferably equal to or more than 45.00 wt.%, even more preferably equal or more than 50.00 wt.%, relative to the total weight of the slurry Seating. It is further understood that the upper limit of the content of solid particles C in the slurry Seating is advantageously equal to or less than 95.00 wt.%, preferably equal to or less than 90.00 wt.%, more preferably equal to or less than 85.00 wt.%, even more preferably equal to or less than 80.00 wt.%, more preferably equal to or less than 70.00 wt.%, most preferably equal to or less than 60.00 wt.%, relative to the total weight of the slurry Seating.

[0142] In an embodiment of the method of the present invention, the content of solid particles C in the slurry Seating, as detailed above, is ranging from 35.00 wt.% to 95.00 wt.%, preferably from 40.00 wt.% to 90.00 wt.%, more preferably from 45.00 wt.% to 85.00 wt.%, more preferably from 50.00 wt.% to 80.00 wt.%, more preferably from 50.00 wt.% to 70.00 wt.%, most preferably from 50.00 wt.% to 60.00 wt.%, relative to the total weight of the slurry Seating.

[0143] As mentioned, the slurry Seating comprises at least one liquid phase.

[0144] Within the context of the present invention, the expression “at least one liquid phase” is intended to denote one or more than one liquid phase.

[0145] In general, the nature of the liquid phase of the slurry Seating may be chosen by the skilled person in the art according to its intended purpose.

[0146] Advantageously, the liquid phase of the slurry Seating is a solvent selected from the group consisting of water, ethanol, isopropanol, acetone, mono-propylene glycol and mixtures thereof.

[0147] The slurry Seating may further comprise at least one additive for improving the viscosity of the slurry Seating. In general, the nature of the at least one additive in the slurry Seating may be chosen by the skilled person in the art according to its purpose. Preferably the at least one additive is a thickener, a defoamer, a dispersing agent, a wetting agent or mixtures thereof. Preferably the additive in the slurry Seating is an organic additive. For example, the thickener in the slurry Seating may be xanthan gum. For example, the dispersing agent in the slurry Seating may be a composition comprising carboxylic acid, such as Dolapix CE 64 ®. For example, the defoamer in the slurry Seating may be an aqueous emulsion of vegetable oils, polyethers and non-ionic emulsifiers, such as Agitan DF 6686 W®.

[0148] Advantageously, the content of the additive in the slurry Seating, as detailed above, is equal to or more than 1 .00 wt.%, preferably equal to or more than 2.00 wt.%, preferably equal to or more than 3.00 wt.%, relative to the total weight of the slurry Seating. It is further understood that the upper limit of the additive in the slurry Seating is advantageously equal to or less than 15.00 wt.%, preferably equal to or less than 10.00 wt.%, more preferably equal to or less than 8.00 wt.%, even more preferably equal to or less than 6.00 wt.%, relative to the total weight of the slurry Seating.

[0149] In an embodiment of the method of the present invention, the content of the additive in the slurry Seating is ranging from 1 .00 wt.% to 15.00 wt.%, preferably from 2.00 wt.% to 10.00 wt.%, preferably from 3.00 wt.% to 8.00 wt.%, preferably from 3.00 wt.% to 6.00 wt.%, relative to the total weight of the slurry Seating. Advantageously, the slurry Seating has a viscosity equal to or more than 70.00 mPa.s, preferably equal to or more than 80.00 mPa.s, preferably equal to or more than 90.00 mPa.s, more preferably equal to or more than 100.00 mPa.s, even more preferably equal to or more than 110.00 mPa.s, most preferably equal to or more than 120.00 mPa.s. It is further understood that the upper limit of the viscosity of the slurry Seating is equal to or less than 200.00 mPa.s.

[0150] The slurry Seating may be prepared by a process comprising a mixing of the various components as comprised in the slurry, as detailed above. Furthermore, it is understood that any order of mixing of the various components as comprised in the slurry Seating, as detailed above, is acceptable.

[0151] Mixing, as detailed above, may be carried out by using a variety of mixing means known in the art. Non-limiting examples of such mixing means are for example bubbling or mechanical mixing such as traditional mixers and blenders, high intensity mixers and electric stirrers.

[0152] It is understood that the skilled person in the art will carry out said mixing according to general practice such as notably using optimal times, weights, volumes and batch quantities. The mixing may be performed at room temperature.

[0153] In general, it is understood that any step of coating known by the skilled person can be used for coating the infiltrated ceramic structure with the aim of forming a coated ceramic structure. Suitable methods of coating at least partly the surface of the infiltrated ceramic structure, as detailed above, with the slurry Si or the slurry Seating, as detailed above, include spraying, flow-coating, impregnating, dipping, spreading, pouring and the like. Preferably, the coating step is performed by at least partly dipping the infiltrated ceramic structure, as detailed above, in the slurry Si or the slurry Seating, as detailed above. Preferably, the coating step is performed by completely dipping the infiltrated ceramic structure, as detailed above, in the slurry Si or the slurry Seating, as detailed above.

[0154] The inventors have found that when the infiltrated ceramic structure is coated with the slurry Si to form the coated ceramic structure, said coated ceramic structure has an improved resistance, particularly to the infiltration of molten metals. Without being bound to this theory, the inventors believe that the coating of the infiltrated ceramic structure prevents the molten metal from entering the open porosity of the coated ceramic structure. The inventors have also found that, when the infiltrated ceramic structure is coated with the slurry Seating comprising solid particles C, the particular particle size dso allows to obtain a coated ceramic structure having an improved resistance, particularly to the infiltration of molten metals, by providing an homogeneous coating over the whole surface of the infiltrated ceramic structure, while limiting or suppressing the cracking of this coating layer, in particular when in contact with molten metal. Preferably, the coating step is a coating of the whole surface of the infiltrated ceramic structure with the slurry Si or the coating Seating, as detailed above.

[0155] When the method according to the present invention comprises a coating step, the slurry Si or the slurry Seating used for the coating step may have a content of solid particles A, or a content of solid particles C, higher than the solid content of the slurry Si or Seating used for the dipping step. Advantageously, the slurry Si or the slurry Seating used for the coating step has a content of solid particles A or C [solid content, herein after] equal to or more than 35.00 wt.%, preferably equal to or more than 40.00 wt.%, more preferably equal to or more than 45.00 wt.%, even more preferably equal or more than 50.00 wt.%, relative to the total weight of the slurry. It is further understood that the upper limit of the content of solid particles A or C in the slurry Si or the slurry Seating used for the coating step is advantageously equal to or less than 95.00 wt.%, preferably equal to or less than 90.00 wt.%, more preferably equal to or less than 85.00 wt.%, even more preferably equal to or less than 80.00 wt.%, more preferably equal to or less than 70.00 wt.%, relative to the total weight of the slurry Si or of the slurry Seating.

[0156] In an embodiment of the method of the present invention, the content of solid particles A in the slurry Si used for the coating step is ranging from 35.00 wt.% to 95.00 wt.%, preferably from 40.00 wt.% to 90.00 wt.%, more preferably from 45.00 wt.% to 85.00 wt.%, more preferably from 50.00 wt.% to 80.00 wt.%, more preferably from 50.00 wt.% to 70.00 wt.%, relative to the total weight of the slurry Si.

[0157] In another embodiment of the method of the present invention, the content of solid particles C in the slurry Seating used for the coating step is ranging from 35.00 wt.% to 95.00 wt.%, preferably from 40.00 wt.% to 90.00 wt.%, more preferably from 45.00 wt.% to 85.00 wt.%, more preferably from 50.00 wt.% to 80.00 wt.%, more preferably from 50.00 wt.% to 70.00 wt.%, relative to the total weight of the slurry Seating.

[0158] Advantageously, when used for the coating step, the slurry Si or the slurry Seating further comprise at least one additive, as detailed above. Preferably, when the method comprises a coating step, the additive comprised in the slurry Si or the slurry Seating is a thickener. In general, the purpose of a thickener is to increase the viscosity of the slurry Si or the slurry Seating. Without being bound to this theory, the thickener aims at preventing the slurry Si or the slurry Seating from further infiltrating the porosity of the ceramic structure thereby improving the coating step.

[0159] Advantageously, the infiltrated and coated ceramic structure, has an open porosity equal to or more than 7.00 %, or equal to or more than 9.00 %, or equal to or more than 11.00 %, or equal to or more than 13.00 %, or equal to or more than 15.00 %, or equal to or more than 17.00 %, or equal to or more than 19.00 %, or equal or more than 21.00 %. It is further understood that the upper limit of the open porosity of the infiltrated ceramic structure, after coating, is advantageously equal to or less than 41 .00 %, preferably equal to or less than 39.00 %, more preferably equal to or less than 37.00 %, more preferably equal to or less than 35.00 %, more preferably equal to or less than 33.00 %, more preferably equal to or less than 31 .00 %, more preferably equal to or less than 29.00 %, even more preferably equal to or less than 27.00 %.

[0160] In an embodiment of the process of the present invention, the open porosity of the infiltrated and coated ceramic structure, as detailed above, is ranging from 7.00 % to 41.00 %, or from 9.00 % to 39.00 %, or from 11.00 % to 37.00 %, or from 13.00 % to 35.00 %, or from 15.00 % to 33.00 %, or from 17.00 % to 31.00 %, or from 19.00 % to 29.00 %, or from 21 .00 % to 27.00 %.

[0161] Advantageously, the infiltrated and coated ceramic structure has an apparent density equal to or more than 1.90 g / cm3, preferably equal to or more than 1.95 g / cm3, more preferably equal to or more than 2.00 g / cm3, more preferably equal to or more than 2.05 g / cm3, more preferably equal to or more than 2.10 g / cm3, more preferably equal to or more than 2.15 g / cm3, more preferably equal to or more than 2.20 g / cm3. It is further understood that the upper limit of the apparent density of the infiltrated ceramic structure, after the coating, is advantageously equal to or less than 2.70 g / cm3, preferably equal to or less than 2.65 g / cm3, more preferably equal to or less than 2.60 g / cm3, more preferably equal to or less than 2.55 g / cm3, more preferably equal to or less than 2.50 g / cm3, more preferably equal to or less than 2.45 g / cm3, more preferably equal to or less than 2.40 g / cm3, even more preferably equal to or less than 2.35 g / cm3.

[0162] In an embodiment of the present invention, the apparent density of the infiltrated and coated ceramic structure, as detailed above, ranges from 1.90 g / cm3to 2.70 g / cm3, preferably from 1 .95 g / cm3to 2.65 g / cm3, more preferably from 2.00 g / cm3to 2.60 g / cm3, more preferably from 2.05 g / cm3to 2.55 g / cm3, more preferably from 2.10 g / cm3to 2.50 g / cm3, more preferably from 2.15 g / cm3to 2.45 g / cm3, more preferably from 2.20 g / cm3to 2.40 g / cm3, even more preferably from 2.20 g / cm3to 2.35 g / cm3.

[0163] Advantageously, the infiltrated and coated ceramic structure has a weight gain equal to or more than 5.00 %, preferably equal to or more than 7.00%, preferably equal to or more than 10.00 %, more preferably equal to or more than 15.00 %. It is further understood that the upper limit of the weight gain of the infiltrated ceramic structure, after the coating is equal to or less than 50.00 %, preferably equal to or less than 40.00 %, preferably equal to or less than 35.00%.

[0164] In an embodiment of the present invention, the weight gain of the infiltrated and coated ceramic structure, is ranging from 5.00 % to 50.00 %, preferably from 7.00 % to 40.00 %, preferably from 10.00 % to 30.00 %, even more preferably from 15.00 to 35.00 %.

[0165] The expression “weight gain”, has the same meaning than detailed above for the infiltrated ceramic structure. The weight gain of the infiltrated and coated ceramic structure is the difference between the initial weight of infiltrated ceramic structure measured before the coating step and the final weight of the infiltrated and coated ceramic structure measured after the coating step, expressed in %.

[0166] The method according to the present invention may further comprise at least one firing step of the infiltrated ceramic structure prior to the coating or / and after the coating of the infiltrated ceramic structure thereby forming a fired ceramic article.

[0167] Preferably, the temperature of the firing step is chosen to achieve sintering of the infiltrated ceramic structure. The definition of pre-sintering, as detailed above equally applies to sintering. It is understood that the skilled person in the art will be able to select the firing temperature for the infiltrated ceramic structure with the aim of sintering the infiltrated ceramic structure.

[0168] Advantageously, the firing step is carried out at a temperature equal to or more than 1400 °C, preferably equal to or more than 1450 °C, more preferably equal to or more than 1500 °C, even more preferably equal or more than 1550 °C. It is further understood that the upper limit of the temperature for the firing step is advantageously equal to or less than 1800 °C, preferably equal to or less than 1750 °C, more preferably equal to or less than 1700 °C, even more preferably equal to or less than 1650 °C.

[0169] In an embodiment of the present invention, the temperature of the firing step, as detailed above, ranges from 1400 °C to 1800 °C, preferably from 1450 °C to 1750 °C, more preferably from 1500 °C to 1700 °C, even more preferably from 1550 °C to 1650 °C.

[0170] Advantageously, the shrinkage of the fired ceramic article is equal to or more than 0.50 %, preferably equal to or more than 0.70 %, preferably equal to or more than 1.00 %, more preferably equal to or more than 1 .20 %, more preferably equal to or more than 1 .50 %. It is further understood that the upper limit of the shrinkage of the fired ceramic article is equal to or less than 5.00 %, preferably equal to or less than 4.00 %, preferably equal to or less than 3.00 %, more preferably equal to or less than 2.00 %.

[0171] In an embodiment of the present invention, the shrinkage of the fired ceramic article is ranging from 0.50 % and 5.00 %, preferably from 0.70 % to 4.00 %, preferably from 1 .00 % to 3.00 %, more preferably from 1 .20 % to 2.00 %, or from 1 .50 % to 2.00 %.

[0172] Within the context of the present invention, the expression “shrinkage”, is intended to refer to the difference in the size of the infiltrated ceramic structure before the firing step and the fired ceramic article after the firing step. In general, the expression “shrinkage” refers to a reduction in size.

[0173] In general, the shrinkage level can be measured by methods known in the art. Unless otherwise stated, in the context of the present invention the method used to measure the shrinkage is a geometric method. Preferably, the shrinkage of an object is the difference between the initial length of the object measured before the firing step and the final length of the object measured after firing step, expressed in %.

[0174] The inventors have found that when the method comprises a firing step, the solid particles A having specifically a dso particle size value of less than 30.00 pm which have been infiltrated in the ceramic structure, serve to improve the sintering and thus improve the mechanical properties of the ceramic article.

[0175] In a preferred embodiment, the method for manufacturing a ceramic article, as detailed above, comprises the steps of:

[0176] Step 1 : providing at least one ceramic structure obtained by a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity of at least 35.00 %, wherein the ceramic compound is selected from the group consisting of aluminum oxide, zirconium oxide, and mixtures thereof and the binder is an organic binder;

[0177] Step 2: providing at least one slurry Si comprising solid particles [solid particles A, herein after] and at least one liquid phase, wherein said solid particles A have a dso particle size value equal or more than 1 .00 pm and less than 30.00 pm, wherein the solid particles A are selected from the group consisting of aluminum oxide, zirconium oxide, zirconium silicate, aluminum silicate, silicon carbide, cerium oxide, titanium oxide, magnesium oxide and mixtures of two or more thereof and wherein the content of solid particles A in the slurry Si [solid content, hereinafter] is at least 50.00 % by weight [wt.%, hereinafter], relative to the total weight of the slurry Si;

[0178] Step 3: at least one dipping of at least part of the ceramic structure in the slurry Si thereby infiltrating at least partly the open pores of the ceramic structure with the solid particles A [infiltrated ceramic structure, hereinafter].

[0179] In an alternative embodiment, the method for manufacturing a ceramic article, as detailed above, comprises the steps of:

[0180] Step 1 : providing at least one ceramic structure obtained by a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity of at least 35.00 %, wherein the ceramic compound is selected from the group consisting of aluminum oxide, zirconium oxide, and mixtures thereof and the binder is an organic binder;

[0181] Step 2: providing at least one slurry Si comprising solid particles [solid particles A, herein after] and at least one liquid phase, wherein said solid particles A have a dso particle size value equal or more than 1 .00 pm and less than 30.00 pm, wherein the solid particles A are selected from the group consisting of aluminum oxide, zirconium oxide, zirconium silicate, aluminum silicate, silicon carbide, cerium oxide, titanium oxide, magnesium oxide and mixtures of two or more thereof and wherein the content of solid particles A in the slurry Si [solid content, hereinafter] is at least 50.00 % by weight [wt.%, hereinafter], relative to the total weight of the slurry Si;

[0182] Step 3: at least one dipping of at least part of the ceramic structure in the slurry Si thereby infiltrating at least partly the open pores of the ceramic structure with the solid particles A [infiltrated ceramic structure, hereinafter].

[0183] Step 4: at least one dipping of the at least part of the infiltrated ceramic structure in the slurry Seating, thereby coating at least partly the infiltrated ceramic structure with the solid particles C. A ceramic article is another aspect of the present invention, said ceramic article comprises:

[0184] - at least one ceramic structure obtained by a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity comprising open pores;

[0185] - solid particles [solid particles A, hereinafter] having a dso particle size value equal or more than 1 .00 pm and less than 30.00 pm, wherein said solid particles A are infiltrated in the open pores of the ceramic structure; wherein the ceramic article has an open porosity of between 7.00 % and 41 .00 %.

[0186] According to one embodiment of the present invention, the ceramic article comprises:

[0187] - at least one ceramic structure obtained by binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity comprising open pores;

[0188] - solid particles [solid particles A, hereinafter] having a dso particle size value equal or more than 1 .00 pm and less than 30.00 pm, wherein said solid particles A are infiltrated in the open pores of the ceramic structure

[0189] - solid particles [solid particles C, hereinafter] having a dso particle size value of between 0.05 pm and 30.0 pm, wherein said solid particles C are coating the infiltrated ceramic structure; wherein the ceramic article has an open porosity of between 7.00 % and 41 .00 %.

[0190] It is further understood that all definitions and preferences, as described above, equally apply for the ceramic article.

[0191] Advantageously, the ceramic article is obtained according to the method of the present invention, as detailed above.

[0192] Advantageously, said ceramic article has an open porosity equal to or less than 34.00 %, preferably equal to or less than 33.00 %, more preferably equal to or less than 32.00 %, more preferably equal to or less than 31 .00 %, more preferably equal to or less than 30.00 %, more preferably equal to or less than 29.00 %, more preferably equal to or less than 28.00 %, even more preferably equal to or less than 26.00 %.

[0193] In an embodiment of the present invention, the open porosity of the ceramic article, as detailed above, is ranging from 7.00 % to 34.00 %, preferably from 7.00 % to 33.00 %, more preferably from 7.00 % to 32.00 %, more preferably from 7.00 % to 31.00 %, more preferably from 7.00 % to 30.00 %, more preferably from 7.00 % to 29.00 %, more preferably from 7.00 % to 28.00 %, even more preferably from 7.00 % to 26.00 %.

[0194] In a preferred embodiment, the ceramic article, as detailed above, comprises:

[0195] - at least one ceramic structure obtained by a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity comprising open pores, wherein said ceramic structure has an open porosity of at least 35.00 %, wherein the ceramic compound is selected from the group consisting of aluminum oxide, zirconium oxide, and mixtures thereof and the binder is an organic binder;

[0196] - solid particles [solid particles A, hereinafter] having a dso particle size value equal or more than 1 ,00 pm and less than 30.00 pm, wherein said solid particles A are infiltrated in the open pores of the ceramic structure and wherein the solid particles A are selected from the group consisting of aluminum oxide, zirconium oxide, zirconium silicate, aluminum silicate, silicon carbide, cerium oxide, titanium oxide, magnesium oxide and mixtures of two or more thereof; wherein the ceramic article has an open porosity of between 7.00 % and 41 .00 %.

[0197] In one embodiment, the ceramic article, as detailed above, comprises:

[0198] - at least one ceramic structure obtained by a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity comprising open pores, wherein said ceramic structure has an open porosity of at least 35.00 %, wherein the ceramic compound is selected from the group consisting of aluminum oxide, zirconium oxide, and mixtures thereof and the binder is an organic binder;

[0199] - solid particles [solid particles A, hereinafter] having a dso particle size value equal or more than 1 ,00 pm and less than 30.00 pm, wherein said solid particles A are infiltrated in the open pores of the ceramic structure and wherein the solid particles A are selected from the group consisting of aluminum oxide, zirconium oxide, zirconium silicate, aluminum silicate, silicon carbide, cerium oxide, titanium oxide, magnesium oxide and mixtures of two or more thereof;

[0200] - solid particles [solid particles C, hereinafter] having a dso particle size value of between 0.05 pm and 30.00 pm, wherein said solid particles C are coating the infiltrated ceramic structure and wherein the solid particles C are selected from the group consisting of aluminum oxide, zirconium oxide, and mixtures thereof; wherein the ceramic article has an open porosity of between 7.00 % and 41 .00 %.

[0201] The use of the ceramic article of the present invention, as detailed above, in a ceramic foundry filter for molten metal filtration is another aspect of the invention.

[0202] It is further understood that all definitions and preferences, as described above, equally apply for the use of the ceramic article in a ceramic foundry filter for molten metal filtration.

[0203] In one embodiment, the ceramic article used in ceramic foundry filterfor molten metal filtration comprises a plurality of holes having an average diameter higher than 1 mm, more preferably from 3 mm to 10 mm.

[0204] It will be understood in the context of the present invention that the plurality of holes of the ceramic article used in a ceramic foundry filter for the molten metal filtration is intended to denote the space of the ceramic article which is not occupied by the structure of the ceramic article. In other words, the plurality of holes is intended to denote the space in which the molten metal may go through the ceramic article.

[0205] The use of the ceramic article of the present invention as detailed above, in a wearresistant part is another aspect of the invention.

[0206] It is further understood that all definitions and preferences, as described above, equally apply for the use of the ceramic article in a wear-resistant part.

[0207] According to one embodiment, the wear-resistant part is for high abrasion application.

[0208] Within the context of the present invention, high abrasion application is intended to denote any application in which abrasive materials are handled.

[0209] Non-limiting examples of abrasive material may include rocks, sand and ores.

[0210] Non-limiting examples of wear resistant part for high abrasion application may include any part of an apparatus used in high abrasion application, such as for example parts of an excavator, an excavation bucket, a material crusher, a conveyor, a loader, or a cable shovel.

[0211] EXAMPLES

[0212] The invention will be now described in further detail with reference to the following examples, whose purpose is merely illustrative and not intended to limit the scope of the invention. Test methods

[0213] Measurements of the open porosity and apparent density

[0214] The measurements of the open porosity and of the apparent density were performed according to the standard ASTM C20 (2022) “Standard Test Methods for Apparent Porosity, Water Absorption, Apparent Specific Gravity, and Bulk Density of Burned Refractory Brick and Shapes by Boiling WateT, as detailed above.

[0215] Slurry

[0216] The slurries were prepared by mixing solid particles A or C, water as solvent and the additive as detailed in tables 1 and 2.

[0217] Table 1 : Slurry used for the dipping step and the coating step in the examples

[0218] Table 2: Slurry used for the dipping step and the coating step in the examples

[0219] Procedure for manufacturing ceramic article

[0220] The following section details how the ceramic article according to the invention was prepared.

[0221] The exact compositions of the Examples, with respect to the type of components contained therein and the related quantities thereof, are described in Tables 1 and 2 above.

[0222] In a first step (i.e. , Step 1 of the method for the manufacturing of the ceramic article), a ceramic structure obtained by a binder jetting 3D ceramic printer using pre-sintered particles of zirconium oxide and cerium oxide (cerabeads ®) having a d?o of 150 pm, as ceramic compound, and an organic binder was provided. Said ceramic structure had an open porosity of 50%. The ceramic structure was in the shape of a filter for molten metal filtration, having a dimension of 100 mm x 100 mm.

[0223] In a following step (i.e., Step 2 of the method for the manufacturing of the ceramic article), the slurries prepared as detailed above were provided, at room temperature and at atmospheric pressure.

[0224] Dipping step

[0225] The ceramic structure was then dipped (i.e., Step 3 of the method for the manufacturing of the ceramic article) for 10 s in the slurry. Example 4 was performed with two successive dipping steps, firstly in a slurry having a solid content (particles A) of 72.0 wt.% and then in a slurry having a solid content (particles A) of 66.0 wt.%, as detailed in table 2. The infiltrated ceramic structures were dried after each dipping step at 120 °C. Coating step

[0226] The infiltrated ceramic structure was then subjected to a coating step by dipping (examples 1 and 4) or by pouring (examples 2 and 3) the infiltrated ceramic structure in the slurries as detailed in tables 1 and 2. The coating was performed over 5 s. The infiltrated and coated ceramic structures were dried after the coating step at 120 °C. Then the infiltrated and coated ceramic structures were fired at 1620 °C thereby forming the ceramic articles.

[0227] Shrinkage and metal test

[0228] In order to evaluate the performance of the ceramic articles, prepared according to the present invention, in terms of hot strength, high resistance and durability, shrinkage was measured after the firing step.

[0229] The experimental results are shown below in Table 3.

[0230] Table 3: Experimental results

[0231] The experimental results as shown in Table 3 first of all clearly demonstrate that the dipping step with the slurry according to the present invention, i.e. , E1 to E4, provides a weight gain. This indicates that the particles A comprised in the slurry Si , infiltrate the open pores of the ceramic structure. Furthermore, the experimental results for E1 to E4 show a second weight gain after the coating step which demonstrates the coating of the infiltrated ceramic structure with the particles comprised in the slurry used for the coating. The shrinkage measured after the firing step also highlights the reduction in open porosity of the ceramic article compared to the ceramic structure used in Step 1. Examples 1-4 showed an open porosity after firing at 1620 °C for 150 min of between 15 to 30%. In particular, the shrinkage for examples 1 and 4 was better than for examples 2 and 3. This is most likely due to the fact that the weight gain after the dipping step was lower for examples 2 and 3.

[0232] Further, the experimental results shown in Table 3 demonstrate that a ceramic article obtained by the method according to the present invention, can be used efficiently as filter for molten metal filtration. Consistently with previous results, the results for examples 2 and 3 were slightly less good than for examples 1 and 4.

Claims

CLAIMS1 . A method for manufacturing a ceramic article, which method comprises the steps of:Step 1 : providing at least one ceramic structure obtained by a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity of at least 35.00 %;Step 2: providing at least one slurry Si comprising solid particles [solid particles A, herein after] and at least one liquid phase, wherein said solid particles A have a dso particle size value equal or more than 1 .00 pm and less than 30.00 pm;Step 3: at least one dipping of at least part of the ceramic structure in the slurry Si thereby infiltrating at least partly the open pores of the ceramic structure with the solid particles A [infiltrated ceramic structure, herein after],2. The method according to claim 1 further comprising, after Step 3, a step of coating at least part of the surface of the infiltrated ceramic structure with the slurry Si.

3. The method according to claim 1 or claim 2 wherein the content of solid particles A in the slurry Si [solid content, hereinafter] is at least 35.00 % by weight [wt.%, hereinafter], relative to the total weight of the slurry Si.

4. The method according to any one of claims 1 to 3 wherein the solid particles A are selected from the group consisting of aluminum oxide, zirconium oxide, zirconium silicate, aluminum silicate, silicon carbide, cerium oxide, titanium oxide, magnesium oxide and mixtures of two or more thereof.

5. The method according to any one of claims 1 to 4 wherein the ceramic compound is selected from the group consisting of aluminum oxide, zirconium oxide, zirconium silicate, aluminum silicate, silicon oxide, silicon carbide, cerium oxide, titanium oxide, titanium carbide, magnesium oxide, tungsten carbide and mixtures of two or more thereof.

6. The method according to any one of claims 1 to 5 wherein the ceramic compound is selected from the group consisting of aluminum oxide, zirconium oxide, cerium oxide, and mixtures thereof, preferably the ceramic compound is a mixture of zirconium oxide and cerium oxide.

7. The method according to any one of claims 1 to 6 wherein the ceramic compound is a pre-sintered ceramic compound.

8. The method according to any one of claims 1 to 7 wherein the ceramic compound consists of solid particles [solid particles B, hereinafter] wherein the solid particles B have a dso particle size value equal to or more than 75.00 pm.

9. The method according to any one of claims 1 to 8 wherein the binder is an organic binder, preferably selected from the group consisting of furane resins, phenolic resins, and mixture thereof.

10. The method according to any one of claims 1 to 9 wherein the liquid phase of the slurry Si is a solvent selected from the group consisting of water, ethanol, isopropanol, acetone and mixtures thereof.

11. The method according to any one of claims 1 to 10 further comprising, after Step 3, a step of drying the infiltrated ceramic structure at a temperature of at least 90 °C.

12. The method according to any one of claims 2 to 11 further comprising a step of firing the infiltrated ceramic structure prior and / or after the coating step at a temperature of at least 1400 °C.

13. A ceramic article comprising:- at least one ceramic structure obtained by a binder jetting 3D ceramic printer using at least one ceramic compound and at least one binder, wherein said ceramic structure has an open porosity comprising open pores;- solid particles [solid particles A, hereinafter] having a dso particle size value equal or more than 1 .00 pm and less than 30.00 pm, wherein said solid particles A are infiltrated in the open pores of the ceramic structure; wherein the ceramic article has an open porosity of between 7.00 % and 41 .00 %.

14. A ceramic article obtained by the method according to any one of claims 1 to 12 wherein said ceramic article has an open porosity of between 7.00 % and 41.00 %.

15. Use of a ceramic article according to claim 13 in a ceramic foundry filter for molten metal filtration.

16. Use of a ceramic article according to claim 13 in a wear-resistant part for high abrasion applications where abrasive materials, preferably selected from rocks, sand and ore, are handled.

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