Niobium nanoparticle preparation, use of the same preparation, and method for obtaining the same preparation

Abstract

The present invention describes the preparation of niobium nanoparticles, their uses, and methods for obtaining them by milling, i.e., a top-down process. The nanoparticle preparations of the present invention solve these and other problems, possessing unique compositions, purities, particle size profiles, and specific surface areas, making them useful in a variety of applications. The present invention also discloses methods for obtaining nanoparticles of niobium-containing mineral species by controlled milling, without chemical reactions or contamination with agents specific to nanoparticle synthesis. Far from being in contrast to the state of the art, the present invention achieves large-scale production of niobium pentoxide nanoparticles with high purity, defined particle size profiles, and very large specific surface areas, enabling their practical use in several industrial applications.

Description

[Technical Field]

[0001] This invention relates to the fields of materials science and nanotechnology. More specifically, the invention describes the preparation of niobium nanoparticles, their use, and a method for obtaining them by grinding, i.e., by a top-down process. For decades, efforts to obtain large quantities of high-purity niobium pentoxide nanoparticles have failed, so this invention represents an achievement previously considered impossible. The nanoparticle preparations of this invention solve these and other problems, possessing unique composition, purity, particle size profile, and specific surface area, making them useful in a variety of applications. This invention also discloses a method for obtaining nanoparticles of niobium-containing mineral species by controlled grinding, without chemical reactions or contamination by agents specific to nanoparticle synthesis. In contrast to the latest technology, this invention achieves large-scale production of high-purity niobium pentoxide nanoparticles, a predetermined particle size profile, and a very large specific surface area, enabling its practical use in several industrial applications. [Background technology]

[0002] Particles of various materials, especially ceramic materials including ceramic oxides, are extremely useful in a wide range of applications. In this field, so-called post-metallurgy is the focus of research by many research groups and companies involved in the development of specialty materials, and size limitations or particle size distribution profiles are important factors in the properties of such materials.

[0003] Of particular importance in relation to the present invention is the emphasis on the difference between (i) preparations containing a small amount of nanoparticles among other particles; (ii) preparations containing particles mainly or entirely within the nanometer particle size range; and (iii) preparations of nanoparticles mainly or entirely within the nanometer particle size range having a defined particle size distribution profile. The present invention provides two of these latter types.

[0004] In this regard, a recent publication by one of the inventors of the present invention (Powder Technology 383(2021)348~355 - Powder grinding and nano-particle sizing: sound, light and illumination) demonstrates how important it is to know about techniques for measuring particle size, especially for accurate descriptions of such sizes at the nanoscale. At the nanoscale, conventional measurement methods (EAS, electroacoustic spectroscopy, and DLS dynamic light scattering) are prone to errors when based on particle volume, and techniques based on the number of particles and their specific surface area are most appropriate at this dimension.

[0005] While niobium particle preparations may ultimately contain a small amount of nanoparticles, the prevalence of much larger particle sizes in the micrometer / micron range hinders the characterization of such preparations as actual nanoparticle preparations. Furthermore, the behavior of nanoscale materials is known to change significantly, and therefore, it is highly desirable to be able to obtain on a large scale preparations containing niobium particles that are mainly or entirely in the nanometer range and of high purity, without the contamination typical of the synthesis process. The present invention solves these and other technical problems.

[0006] Due to the unique properties of niobium, an element produced on a large scale in Brazil, ceramic oxides, particularly niobium pentoxide, have been explored for a variety of applications. Despite Brazil being one of the world's leading producers of niobium and the vigorous research activities in this important material, decades of unsuccessful attempts have been made to obtain large-scale and high-purity preparations of niobium nanoparticles, primarily or entirely in the nanoparticle range. This invention solves these and other technical problems.

[0007] The literature includes examples of methods for synthesizing niobium-containing nanoparticles using a method called bottom-up synthesis. However, because such methods are bottom-up or synthesis methods, they involve chemical reactions, agents, and products, and the resulting products usually contain a large amount of contaminants, including material residues or reaction by-products.

[0008] Furthermore, nanoparticles obtained by bottom-up methods are limited to specific chemical species that are reaction products. Moreover, these methods are not technically and / or economically feasible on a large scale, which is partly why preparations of niobium nanoparticles that are stable, pure, and have a particle size distribution mainly or entirely within the nanometer range are not available on an industrial scale. The present invention solves these and other technical problems.

[0009] Methods of grinding / crushing / spraying transition metals are typically aimed at increasing their specific surface area and enabling a variety of industrial applications. In the case of niobium or niobium-containing materials, particularly niobium pentoxide, known methods are limited to obtaining particles with a particle size distribution in the micrometer range, and as of the filing date of this patent application, no milling method that achieves the acquisition of a preparation containing entirely nanoparticles was known to the inventors of this invention.

[0010] Niobium has a higher dielectric constant than some other transition metals, making it a very useful material in electronic components such as capacitors. However, obtaining metallic niobium powder by grinding requires the use of a liquid dispersion medium, and the heat generated by the contact between the niobium powder and the dispersion medium, and / or grinding, causes oxygen present in the adsorption medium to adsorb onto niobium hydride, forming niobium oxide which impairs the LC value (inductor / capacitor or inductance / capacitance). This results in a wide dispersion of the LC value and undermines the reliability of the material for use in capacitors and / or other electronic components. Furthermore, until the present invention, obtaining mainly or entirely nanometer-sized particles of niobium and niobium pentoxide by milling (a top-down process) was considered a technically impossible challenge and the objective of decades of stalled attempts. The present invention solves these and other technical problems.

[0011] In a search of the latest technologies in scientific literature and patent documents, the following documents related to the subject were found.

[0012] Patent PI 0601929-3, granted to and now extinguished by the Instituto Militar de Engenharia, discloses obtaining a homogeneous mixture of niobium oxide in alumina on a nanometer scale using sol-gel technology. The method obtains a mixed oxide of Nb2O5 in Al2O3 in an aqueous medium by sol-gel technology, controlling the hydrolysis and condensation rates of this transition metal using acetylacetone to obtain nanometer-sized particles of these mixed oxides by reaction.

[0013] Japanese Patent Application No. 10-242004 discloses a technique for partial nitriding of niobium powder to increase the LC value. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0014] U.S. Patent No. 4,084,965 discloses obtaining niobium powder (also called columbium powder) having a particle size of 5.1 microns. The powder is obtained by hydrogenating and grinding a niobium ingot, the grinding being assisted by the addition of a small amount of phosphorus-containing material (5-600 ppm of elemental phosphorus), preferably in liquid form, to facilitate mixing. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0015] U.S. Patent Application 2004 / 0168548 discloses a method for obtaining niobium powder having a particle size range of 10 to 500 microns. This method involves milling and is intended to obtain niobium powder for use in capacitors. In the method, niobium hydride or niobium hydride alloy is milled at a temperature of -200 to 30°C in the presence of a dispersion medium. The dispersion medium used is selected from water, organic solvents, or liquefied gases. Dehydrogenation of the niobium hydride powder or niobium hydride alloy powder is performed at a temperature of 100 to 1000°C after milling. The properties of the resulting niobium powder are such that the specific surface area is 0.5 to 40 m². 2 The density is 0.5-4 g / mL; the peak pore size is 0.01-7 microns; and the oxygen content is 3 wt% or less. In the above method, it is undesirable for the average particle size of the granular powder to be less than 10 microns, because the powder reduces the efficiency of the method and impairs the fluidity of the material. The preparation of niobium pentoxide nanoparticles as described in the present invention is not disclosed.

[0016] Brazilian patent application PI 0401882-6, filed and shelved by CBMM, discloses a method for producing metallic niobium and tantalum powders having high chemical purity, a large surface area, suitable morphology and porosity, and low apparent density. The method comprises the steps of: obtaining a fine powder; surface oxidation in a controlled manner; reducing the oxide layer with an alkali metal or alkaline earth metal in a molten salt bath or molten salt mixture; dissolving and leaching the formed cake; and filtering, washing, and drying the obtained product. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0017] Brazilian patent PI 0105773-1, granted to CBMM, discloses a method for producing Nb-Zr alloy powder containing 0.1% to 10% zirconium. The method involves hydrogenating, milling, and dehydrogenating a niobium-zirconium (Nb-Zr) alloy to produce a powder with controlled impurity levels. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0018] The Brazilian patent application PI 0303252-9, filed by IPT / SP, discloses a method for producing niobium monoxide (NbO) powder with high purity, a large specific surface area, controlled oxygen and nitrogen contents, an appropriate morphology, and proper porosity, which is intended to be used in the manufacture of capacitors. The method is characterized by a two-step reduction of niobium pentoxide (Nb2O5), including a first step of reducing niobium pentoxide (Nb2O5) to niobium dioxide (NbO2) with a diameter of 0.3 - 0.6 mm by a reducing gas, and a second step of obtaining niobium monoxide (NbO) by a collector material under appropriate temperature and time conditions for the formation of NbO. The NbO particles are large in size compared to the nanoscale. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0019] The Brazilian patent application PI 0402611-0, filed by IPT / SP and rejected, discloses a method for producing niobium monoxide (NbO) powder with high purity, a large specific surface area, controlled oxygen and nitrogen contents, an appropriate morphology, and proper porosity, which is used in the manufacture of capacitors. The method is characterized by a two-step reduction of niobium pentoxide (Nb2O5), including a first step of reducing niobium pentoxide (Nb2O5) to niobium dioxide (NbO2) by a reducing gas, and a second step of obtaining niobium monoxide (NbO) by the complete or partial transfer of oxygen to fine powder of metallic niobium (Nb) having a morphology and physical properties similar to NbO2, which refers to the conversion of NbO2 to NbO. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0020] The Brazilian patent PI 0106058-9, filed by CBMM and transferred to IPT / SP, discloses a method for producing high-purity niobium powder with a large specific surface area and a controlled oxygen level. The method involves an alkali metal or alkaline earth metal (Me x NbO y, where Me is an alkali metal or an alkaline earth metal, x = 0.5 - 3, and y = 2 - 4), including one step of reducing the niobate with a metal of the same nature, followed by an acid leaching / washing step to remove the alkali metal or alkaline earth metal oxide (or the excess alkali metal or alkaline earth metal used in the reduction) present in the final product. The patent also protects the niobium powder thus obtained. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0021] The Brazilian patent application BR 112020014972-1 (International Publication No. 2019145298) filed by Evonik Operations GMBH discloses a composition of polymer inorganic nanoparticles and a method for preparing the same. The nanoparticles disclosed in the above document are polymers selected from several types of polymers including metal chalcogenides containing sulfur, selenium, tellurium, or oxygen, and acrylates, acids, halides, or esters, and are intended to be used as lubricants. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0022] The patent application BR 102017017416-6 filed by UFRN discloses a synthetic route for iron niobate by high-energy ball milling. The above document discloses the synthesis of iron niobate (FeNbO4) by mechanically grinding (wet method) niobium pentoxide (Nb2O5), metallic iron (α-Fe), and distilled water (H2O) at 55% - 65%, 20% - 30%, and 10% - 20% by mass percentage respectively, with a rotation of 100 - 500 rpm, and then heat-treating at 1000 - 1500 °C for 1 - 5 hours. The resulting product contains a two-phase of 97.82% iron niobate and 2.18% hematite (α-Fe2O3). This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0023] Japanese patents PI0110333-4 and PI0206094-9, granted to Showa Denko K.K. in Japan and subsequently expired, disclose niobium powder and sintered bodies containing the powder. The focus of the aforementioned documents is on the manufacture of capacitors, and the inventors found that controlling the nitrogen concentration is one of the keys to obtaining a capacitor with good performance. In the aforementioned documents, the niobium powder used is micrometer-sized (up to 1000 μm), obtained from ingots and jet mills, and is 0.5 to 40 m 2 It has a surface area of ​​ / g. This does not disclose the preparation of niobium pentoxide nanoparticles as described in the present invention.

[0024] Patent application PI 0114919-9, filed and shelved by Showa Denko K.K., discloses a capacitor powder containing niobium. The powder is hydrogenated and at least partially nitrided niobium. The example includes supplying niobium metal particles having dimensions of 0.1 to 5 mm in diameter to a reaction tower supplied with a gas for halogenation. The resulting halogenated niobium powder is reduced with hydrogen gas to 4 to 30 m 2 Clusters having a specific surface area of ​​1 / g can be formed and used to sinter useful sintered bodies for capacitor preparation. This does not disclose the preparation of niobium pentoxide nanoparticles as described in the present invention.

[0025] Cabot Corp.'s U.S. Patent No. 6,375,704,B1 discloses a method for preparing niobium powder preparations and niobium powder flakes for use in capacitors. The method includes grinding niobium chips to form flakes, and then subjecting the resulting flakes to a deoxygenation step, preferably with magnesium. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0026] Patent application PI0401114-7, filed and shelved by CBMM, discloses a niobium powder (pentoxide or monoxide) containing a controlled amount of vanadium, obtained by coprecipitation. The specific surface area of ​​the niobium pentoxide or niobium monoxide in the said document is 0.4 m². 2 / g~30.0m 2 / is. A sponge form containing niobium oxide is disclosed, and the preparation of niobium pentoxide nanoparticles such as those of the present invention is not disclosed.

[0027] Patent application PI0508759-7, filed and shelved by Mitsui Mining & Smelting Co., Ltd., discloses niobium oxide for use in capacitors and a method for obtaining it. In the said document, niobium oxide having a lower oxidation number obtained from niobium oxide having a higher oxidation number is disclosed, and the resulting product (NbO) has an average particle size d50 of 2 microns and 2.0 m 2 / g to 50.0 m 2 / g of specific surface area (BET value). The manufacturing method includes stepwise dry reduction of niobium pentoxide in two steps to produce niobium monoxide. In the stepwise reduction, a carbon-containing reducing agent is used in at least one of the two steps, and it is preferable that the environmental temperature and pressure are maintained within a predetermined range in each step. This does not disclose the preparation of niobium pentoxide nanoparticles such as those of the present invention.

[0028] Patent application PI 0711243-2, filed and shelved by Mitsui Mining & Smelting Co., Ltd., discloses porous-structured niobium monoxide for use in capacitors. In the said document, it is disclosed that niobium monoxide has a specific surface area (BET value) of 10.7 m 2 / g. This does not disclose the preparation of niobium pentoxide nanoparticles such as those of the present invention.

[0029] U.S. Patent Application No. 2009 / 0256014A1 discloses a milling method for niobium hydride using a milling aid having a density of 3.6 g / cm 3 and a crushing hardness value of 1.5 MPa·m 1 / 2 or more, such as silicon nitride balls. This does not disclose the preparation of niobium pentoxide nanoparticles such as those of the present invention.

[0030] Chinese Patent No. 100381234C by Cabot Corp., a family member of Brazilian Patent Application PI0009107 (rejected), discloses a method for producing niobium powder by milling. This method requires grinding a metal powder at high temperature and in the presence of at least one liquid solvent. A method for forming aggregated metal by wet milling of the metal powder is also disclosed, in which at least one liquid fluorine-treated fluid is present during the wet milling process. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0031] Chinese Patent Application No. 101798227A by Guilin Tech Gut University discloses a method for the solid-phase synthesis of nanometer powders of niobate / tiantate salts. The method comprises grinding niobium pentoxide, sodium carbonate, potassium carbonate, titanium dioxide, and bismuth trioxide in a ball mill to purify the particles, and then calcining them in a specified stoichiometric ratio. The solid-phase reaction results in the formation of powders of sodium-potassium niobate, sodium bismuth titanate, or other mixtures, with particles of 80 nanometers or less. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0032] U.S. Patent Application 2007185242A1, filed and abandoned by Huang Yuhong, discloses a low-temperature curing ink containing nanometer-sized metal hydroxides. The focus of the said document is a composition for coating electrodes or capacitors. The composition comprises submicron particles obtained by a mechanochemical method using ruthenium hydroxide nanoparticles. In the said document, the metal hydroxide nanoparticles are produced by reacting a metal chloride with sodium hydroxide in water. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0033] U.S. Patent Application 2020391294, filed by the University of Missouri, discloses a method for preparing a powdered metal-ceramic composite material. In this method, a mill is used to grind metal powder together with ceramic nanoparticles to produce a metal-ceramic composite material. The mill balls and the interior of the mill are ceramic. This does not disclose the preparation of niobium pentoxide nanoparticles as in the present invention.

[0034] Based on the literature reviewed, no literature prior to or proposing the teachings of the present invention was found. [Overview of the project] [Problems that the invention aims to solve]

[0035] This invention solves several recent problems relating to the preparation of niobium having a nanometer particle size distribution, mainly or entirely. [Means for solving the problem]

[0036] One of the objectives of the present invention is to provide a niobium nanoparticle preparation having high purity.

[0037] One of the objectives of the present invention is to provide a preparation of niobium particles with a chemically defined composition.

[0038] One of the objectives of the present invention is to provide a preparation of niobium pentoxide particles having a particle size range of d50 to d99 within the nanometer range.

[0039] One of the objectives of the present invention is to provide a preparation of niobium pentoxide particles having a particle size range of d90 to d99 within the nanometer range.

[0040] In some embodiments, the niobium pentoxide nanoparticle preparations have an average particle size (d50) of 178-239 nm.

[0041] One of the objectives of the present invention is to provide a preparation of niobium particles within a particle size range of less than 100 nanometers.

[0042] In some embodiments, the niobium pentoxide nanoparticle preparation has a particle size distribution of d10: 9-27 nm; d50: 16-67 nm; and d90: 33-94 nm.

[0043] In other embodiments, the niobium pentoxide nanoparticle preparation has a particle size distribution of d10: 14-110 nm; d50: 29-243 nm; and d90: 89-747 nm.

[0044] One of the objectives of the present invention is to provide a solution for 0.5 to 150 m 2 The objective is to provide a preparation of niobium particles having a specific surface area of ​​ / g.

[0045] In one embodiment, the niobium pentoxide nanoparticle preparation is 40-70 m 2 It has an average specific surface area per gram.

[0046] The nanoparticle preparations of the present invention are useful in several applications, including: adjusting or improving the mechanical properties of steel, metallic alloys and non-metallic alloys, ceramics and / or polymers; doping materials to modify electromagnetic properties for use in electronic components, battery cells, energy storage systems, solar panels, sensors, and piezoelectric actuators; adjusting the optical properties of glass or other transparent or translucent materials; use as a component of catalysts; and preparing stable liquid / colloidal compositions.

[0047] In one embodiment, the nanoparticle preparation of the present invention enabled the preparation of a stable liquid composition in which the nanoparticles remained suspended for a long period of time, resulting in a long shelf life.

[0048] Therefore, one of the objectives of the present invention is the use of niobium nanoparticles of the present invention in the preparation of stable liquid / colloidal compositions.

[0049] Another object of the present invention is to provide a method for preparing niobium nanoparticle preparations by a top-down approach, i.e., by grinding without the use of chemical or mechanochemical synthesis. The method is large-scale and suitable in terms of the economic viability and efficient utilization of the preparations.

[0050] The method of the present invention is, The steps include: supplying niobium particles to a grinding device selected from a high-energy mill and a steam mill; • In high-energy mills: • Suspend the particles to be ground in a liquid at a concentration of 1-90% m / m, and stabilize the suspension until a stable colloidal suspension is obtained; - Place the suspension and grinding balls having a selected diameter of 5 μm to 1.3 mm into the grinding chamber; adjust the mill rotation speed between 500 and 4500 rpm; grind the particles at a temperature of less than 60°C; or In a jet mill or steam mill with a superheated fluid, feed particles smaller than 40 micrometers; adjust the speed of the air classifier between 1,000 and 25,000 rpm; adjust the compressed vapor pressure between 10 and 100 bar; and adjust the temperature between 230 and 360°C. The steps include adjusting the grinding conditions selected from one of the following; The steps include grinding the particles until a desired particle size distribution profile is obtained. Includes.

[0051] In one embodiment, stabilization of the colloidal suspension to be placed in the grinding chamber of the high-energy mill mentioned above is selected from adjusting the pH of the polar liquid medium to a range of 2 to 13 and optionally adding a surfactant; or adding a surfactant to a non-polar liquid medium.

[0052] In one embodiment, a method for obtaining niobium nanoparticles involves milling in a high-energy mill operating with spheres of special materials such as zirconia, yttria-stabilized zirconia, niobium pentoxide-stabilized zirconia, or a combination thereof, by adjusting specific parameters.

[0053] In another embodiment, a method for obtaining niobium nanoparticles includes milling in a jet mill or steam mill having superheated steam by adjusting specific parameters.

[0054] One aspect of the present invention is shown below, but the present invention is not limited thereto. [Invention 1] A nanoparticle preparation characterized by containing 95 wt% or more of niobium particles, wherein 50% to 99% of the particles (d50 to d99) are within a particle size range of 5 to 1000 nanometers (nm). [Invention 2] A nanoparticle preparation according to Invention 1, characterized in that 90% to 99% of the particles (d90 to d99) are within a particle size range of 5 to 1000 nanometers (nm). [Invention 3] A preparation of nanoparticles according to invention 1 or 2, characterized in that it contains niobium particles with a content of 99 wt% or more. [Invention 4] A preparation of nanoparticles according to any one of inventions 1 to 3, characterized in that the nanoparticles are niobium pentoxide. [Invention 5] A preparation of nanoparticles according to any one of Inventions 1 to 4, characterized in that the particle size distribution profile is d10: 14~110 nm; d50: 29~243 nm; and d90: 89~747 nm. [Invention 6] A preparation of nanoparticles according to any one of Inventions 1 to 4, characterized in that the particle size distribution profile is d10 70~100nm; d50 170~240nm; d90 400~580nm. [Invention 7] A preparation of nanoparticles according to any one of Inventions 1 to 4, characterized in that the particle size distribution profile is d50 10-178 nm; d80 10-300 nm; d90 10-400 nm. [Invention 8] A nanoparticle preparation according to any one of Inventions 1 to 4, characterized in that 90% to 99% of the particles (d90 to d99) are within a particle size range of 100 to 1000 nm. [Invention 9] A nanoparticle preparation according to any one of Inventions 1 to 4, characterized in that 90% to 99% of the particles (d90 to d99) are within a particle size range of 5 to 100 nm. [Invention 10] A nanoparticle preparation according to Invention 9, characterized in that the particle size distribution profile is d10: 9~27 nm; d50: 16~67 nm; d90: 33~94 nm. [Invention 11] Specific surface area of ​​0.5 to 150 m² 2 A preparation of nanoparticles according to any one of Inventions 1 to 4, characterized in that it is / g. [Invention 12] Average specific surface area is 40-70 m² 2 A nanoparticle preparation according to Invention 11, characterized in that it is / g. [Invention 13] The use of a nanoparticle preparation according to any one of Inventions 1 to 12, characterized in that it is for obtaining other preparations of particles or nanoparticles having adjusted rheological properties, adjusted degree of packing or porosity, and adjusted fluidity of the final preparation. [Invention 14] Use of a nanoparticle preparation according to any one of Inventions 1 to 12, characterized in that it is for the preparation of a catalyst, stable colloidal composition; steel, metallic alloys and non-metallic alloys, ceramics and / or polymers; composite materials, electronic components, battery cells, energy storage systems, piezoelectric sensors and actuators, solar panels; glass, glass ceramics, transparent and translucent materials. [Invention 15] The steps include: supplying niobium particles to a grinding device selected from a high-energy mill, a ball mill, and a steam mill; In a high-energy mill: Suspend the particles to be ground in a liquid at a concentration of 1-90% m / m and stabilize the suspension until a stable colloidal suspension is obtained; place the suspension and grinding balls having a selected diameter of 5 μm-1.3 mm into the grinding chamber; adjust the mill rotation speed between 500 and 4500 rpm; grind the particles at a temperature below 60°C; or In a jet mill or steam mill with a superheated fluid, feed particles smaller than 40 micrometers; adjust the speed of the air classifier between 1,000 and 25,000 rpm; adjust the compressed vapor pressure between 10 and 100 bar; and adjust the temperature between 230 and 360°C. The steps include adjusting the grinding conditions selected from one of the following; The steps include grinding the particles until a desired particle size distribution profile is obtained. A method for obtaining niobium nanoparticles, including [the specified element]. [Invention 16] The method according to Invention 15, characterized in that the colloidal suspension is stabilized by adjusting the pH of a polar liquid medium to a range of 2 to 13 and optionally adding a surfactant, or by adding a surfactant to a non-polar liquid medium. [Invention 17] The method according to invention 15 or 16, further comprising a pre-grinding step of niobium particles before the step of supplying them to a grinding device, characterized in that the pre-grinding is carried out until an average particle size of less than 40 micrometers is reached. [Invention 18] The method according to Invention 17, characterized in that the preliminary grinding is performed in a ball mill, a disc mill, a high-energy mill, or a jet mill. [Invention 19] • Micrometer-sized niobium pentoxide (Nb) in a high-energy mill 2 O 5 ) Steps of supplying particles; The steps include supplying liquid to the mill and adjusting the pH to a range of 5 to 10; The steps include: supplying balls having a selected diameter of 50 μm to 400 μm to the mill; • A step to adjust the mill rotation speed between 2000 and 4000 rpm; The steps include grinding the particles at a temperature below 60°C until the desired particle size profile is obtained. A method according to invention 15 or 16, characterized by including the following: [Invention 20] The method according to Invention 15, characterized in that the high-energy mill is of the agitated medium type, the spheres are selected from zirconia, silicon carbide, and alumina, and the spheres are optionally stabilized with yttria, niobium pentoxide, or a combination thereof. [Invention 21] The method according to invention 15 or 17, characterized in that the jet mill or steam mill at the superheated temperature is adjusted by the following parameters: rotation of an air classifier at 20,000 rpm; compressed vapor pressure of 50 bar; and superheated fluid temperature of 280°C. These and other objects of the present invention will be immediately apparent to those skilled in the art and are described in detail below. [Brief explanation of the drawing]

[0055] The following diagram is shown.

[0056] [Figure 1] Figure 1 shows the particle size distribution of an embodiment of the niobium (Nb2O5) nanoparticle preparation of the present invention, and displays the particle size profile measured by laser scattering using a FRITSCH brand Analysette 22 Nano Tecplus. The particle size distribution, i.e., the equivalent diameter based on particle volume in nanometers (horizontal axis), the relative fraction of nanoparticles (vertical axis on the left), and the cumulative fraction (vertical axis on the right) are shown.

[0057] [Figure 2] Figure 2 shows photographs of precipitation tests at different pH levels for suspensions formed from Nb2O5 particles in aqueous solutions adjusted with HCl or NaOH to change the pH of the medium. Different equilibrium pH levels are shown in numbered test tubes 2, 4, 9, and 12.

[0058] [Figure 3] Figure 3 shows photographs of test tubes used in stabilization tests according to the time (storage period) used in turbidimetric analysis with a TURBISCAN instrument, and shows a test tube containing a suspension of niobium nanoparticles at pH 9 after evaluation for 6 hours.

[0059] [Figure 4] Figure 4 shows the particle size distribution of ground niobium pentoxide as a function of grinding time in a high-energy mill (sampling frequency). The equivalent particle diameter in nm is shown on the x-axis, and the frequency in % is shown on the y-axis.

[0060] [Figure 5] Figure 5 shows the particle size distribution as a function of the cumulative volume of the pulverized niobium pentoxide sample. The equivalent diameter in nm is shown on the x-axis, and the cumulative volume in % is shown on the x-axis.

[0061] [Figure 6] Figure 6 shows the cumulative distribution profile of Nb2O5 particles in alcohol used as a dispersant at the jet mill inlet. The equivalent diameter in microns is shown on the x-axis, the volume % is shown on the left y-axis, and the cumulative volume % is shown on the right y-axis.

[0062] [Figure 7] Figure 7 shows the cumulative particle distribution profile of Nb2O5 particles in alcohol used as a dispersant at the jet mill outlet. The equivalent diameter in microns is shown on the x-axis, the volume % is shown on the left y-axis, and the cumulative volume % is shown on the right y-axis.

[0063] [Figure 8]Figure 8 shows curves corresponding to the particle size distribution profiles of a commercially available product containing niobium pentoxide (curve A = input) and a niobium pentoxide preparation after pre-grinding (curve B). The equivalent particle diameter in micrometers is shown on the x-axis, and the cumulative volume in percent is shown on the y-axis.

[0064] [Figure 9] Figure 9 shows curves corresponding to the particle size distribution profiles of a commercially available product containing niobium pentoxide (curve A = input) and a niobium pentoxide preparation after pre-grinding (curve B). The equivalent particle diameter in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0065] [Figure 10] Figure 10 shows the curve corresponding to the particle size distribution profile (curve C) of preparations of niobium pentoxide nanoparticles that are entirely within the nanometer range, with particles ranging from 74 to 747 nm. The equivalent diameter of the particles in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0066] [Figure 11] Figure 11 shows the curve corresponding to the particle size distribution profile (curve D) of niobium pentoxide nanoparticle preparations that are entirely within the nanometer range, with particles ranging from 20 to 206 nm. The equivalent diameter of the particles in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0067] [Figure 12] Figure 12 shows the curve corresponding to the particle size distribution profile (curve E) of niobium pentoxide nanoparticle preparations, which are entirely within the nanometer range and have particles between 8 and 89 nm. The equivalent diameter of the particles in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0068] [Figure 13] Figure 13 shows a single graph of curves corresponding to the particle size distribution profiles (curves C, D, and E) of three different preparations of niobium pentoxide after pre-grinding. The equivalent particle diameter in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0069] [Figure 14] Figure 14 shows a single graph of curves corresponding to the particle size distribution profiles (curves C, D, and E) of three different preparations of niobium pentoxide after pre-grinding. The equivalent particle diameter in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis. [Modes for carrying out the invention]

[0070] The present invention solves several cutting-edge problems and provides a preparation of niobium nanoparticles that simultaneously intends technical characteristics such as particles mainly or entirely within the nanometer particle size range; high purity; and an industrial-scale process that enables economical supply and use. The preparation is also called a preparation of niobium nanoparticles.

[0071] In the present invention, the term "niobium particles" encompasses a variety of niobium-containing chemical substances, including niobium metal, niobium oxides, hydrates, hydrides, carbides, or nitrides, niobium iron, or niobium bonded to other metals or transition metals, or combinations thereof. This also includes niobium pentoxide.

[0072] The present invention is also defined by the following provisions.

[0073] A preparation of nanoparticles containing 95 wt% or more niobium particles, with 50% to 99% of the particles (d50 to d99) being within a particle size range of 5 to 1000 nanometers (nm).

[0074] A preparation of nanoparticles containing 95 wt% or more niobium particles, with 90% to 99% of the particles (d90 to d99) being within a particle size range of 5 to 1000 nanometers (nm).

[0075] A preparation of nanoparticles as defined above, containing 99 wt% or more niobium particles.

[0076] A preparation of nanoparticles as defined above, wherein the nanoparticles are niobium pentoxide.

[0077] A preparation of nanoparticles as defined above, having a particle size distribution of d10: 14~110 nm; d50: 29~243 nm; and d90: 89~747 nm.

[0078] A preparation of nanoparticles as defined above, having a particle size distribution of d10 at 70-100 nm; d50 at 170-240 nm; and d90 at 400-580 nm.

[0079] A preparation of nanoparticles as defined above, having a particle size distribution of d50 at 10-178 nm; d80 at 10-300 nm; and d90 at 10-400 nm.

[0080] A preparation of nanoparticles as defined above, in which 90% to 99% of the particles (d90 to d99) are within the particle size range of 100 to 1000 nm.

[0081] A preparation of nanoparticles as defined above, in which 90% to 99% of the particles (d90 to d99) are within a particle size range of 5 to 100 nm.

[0082] A preparation of nanoparticles as defined above, having a particle size distribution of d10: 9~27nm; d50: 16~67nm; d90: 33~94nm.

[0083] 0.5~150m 2 A preparation of nanoparticles as defined above, having a specific surface area of ​​ / g.

[0084] 40-70m 2 A preparation of nanoparticles as defined above, having an average specific surface area of ​​ / g.

[0085] Use of the above nanoparticle preparations to adjust the rheological properties of other particle or nanoparticle preparations, or to adjust the degree of packing, fluidity, porosity, or other properties of the final preparation.

[0086] Stable colloidal compositions; steel, metallic alloys and non-metallic alloys, ceramics, and / or polymers; electronic components, battery cells, energy storage systems, piezoelectric sensors and actuators, solar panels; glass, glass ceramics, or other transparent and translucent materials; use of the above nanoparticle preparations for catalyst preparation.

[0087] The steps include: supplying niobium particles to a grinding device selected from a high-energy mill and a steam mill; • In high-energy mills: • Suspend the particles to be ground in a liquid at a concentration of 1-90% m / m, and stabilize the suspension until a stable colloidal suspension is obtained; - Place the suspension and grinding balls having a selected diameter of 5 μm to 1.3 mm into the grinding chamber; adjust the mill rotation speed between 500 and 4500 rpm; grind the particles at a temperature of less than 60°C; or In a jet mill or steam mill with a superheated fluid, feed particles smaller than 40 micrometers; adjust the speed of the air classifier between 1,000 and 25,000 rpm; adjust the compressed vapor pressure between 10 and 100 bar; and adjust the temperature between 230 and 360°C. The steps include adjusting the grinding conditions selected from one of the following; • A step of grinding the particles until the desired particle size profile is obtained. A method for obtaining niobium nanoparticles, including [the specified element].

[0088] The above method for stabilizing a colloidal suspension to be placed in the grinding chamber of a high-energy mill is selected from adjusting the pH of a polar liquid medium to a range of 2 to 13 and optionally adding a surfactant; or adding a surfactant to a non-polar liquid medium.

[0089] The method described above, further comprising a pre-grinding step of niobium particles before the step of supplying them to a grinding device, wherein the pre-grinding is carried out until an average particle size of 1 to 40 micrometers is reached.

[0090] A method wherein the preliminary grinding is performed using a ball mill, a disc mill, or a high-energy mill.

[0091] A method in which the preliminary grinding is performed using a jet mill.

[0092] The above method, wherein the high-energy mill is of the agitated medium type, the spheres are selected from zirconia, silicon carbide, and alumina, and the spheres are optionally stabilized with yttria, niobium pentoxide, or a combination thereof.

[0093] The above method, where the operating pH in the mill is 6-10.

[0094] The above method, where the operating temperature in the mill is 30-40°C.

[0095] In one embodiment, a preparation of niobium pentoxide (Nb2O5) nanoparticles having a purity of 99% or more is provided.

[0096] In one embodiment, the niobium nanoparticle preparation of the present invention has a particle size of 5 to 1000 nanometers. In some embodiments, the nanoparticle preparation of the present invention comprises particles having a specified particle size fraction, for example, a preparation having particles that are entirely 100 to 1000 nm, a preparation having particles that are entirely 5 to 100 nanometers, and a preparation having intermediate particles and a particle size fraction of a specified value.

[0097] In some embodiments of the present invention, as is already practiced in the art, the distribution of particle size fractions is defined by d10, d50, d90, and optionally d99, where the notation reflects the cumulative volume % of the particles corresponding to each notation, with d10 referring to 10% of the particle volume, d50 to 50% of the volume, and so on.

[0098] In some embodiments, the present invention provides preparations of niobium particles within a particle size range of less than 100 nanometers.

[0099] In some embodiments, the niobium pentoxide nanoparticle preparation has a particle size distribution of d10: 9-27 nm; d50: 16-67 nm; and d90: 33-94 nm.

[0100] In other embodiments, the niobium pentoxide nanoparticle preparation has a particle size distribution of d10: 14-110 nm; d50: 29-243 nm; and d90: 89-747 nm.

[0101] In some embodiments, the present invention relates to 50-148m 2 The present invention provides a preparation of niobium particles having a specific surface area of ​​ / g.

[0102] In one embodiment, the niobium pentoxide nanoparticle preparation is 62.07m 2 It has an average specific surface area per gram.

[0103] In one embodiment, a preparation of niobium pentoxide nanoparticles having an average particle size (d50) of 16 nm is provided. In another embodiment, the niobium pentoxide nanoparticle preparation has an average particle size (d50) of 29 nm. In yet another embodiment, the niobium pentoxide nanoparticle preparation has an average particle size (d50) of 67 nm. In yet another embodiment, the niobium pentoxide nanoparticle preparation has an average particle size (d50) of 178 nm.

[0104] The nanoparticle preparations of the present invention are useful in several applications, including the preparation of stable colloidal suspensions; the modification or improvement of the mechanical properties of steel, metallic alloys and non-metallic alloys, ceramics and / or polymers; doping materials to modify electromagnetic properties for use in electronic components, battery cells, energy storage systems, solar panels, sensors, and piezoelectric actuators; the modification of optical properties of glass or other transparent materials; and their use as catalyst components.

[0105] In one embodiment, the use of the nanoparticle preparation of the present invention resulted in a stable liquid composition or colloidal suspension in which the nanoparticles remained suspended for a long period of time, thus providing a long shelf life.

[0106] The method for obtaining niobium nanoparticles differs from other similar methods in that it is a top-down process that does not involve chemical reactions or mechanochemistry. Because this method does not add impurities or produce reaction products, as in bottom-up, synthesis, or modern mechanochemical methods, the fact that pure or highly purified niobium particles are used for grinding ensures the availability of high-purity nanoparticle preparations.

[0107] The method of the present invention is, The steps include: supplying niobium particles to a grinding device selected from a high-energy mill and a steam mill; • In high-energy mills: • Suspend the particles to be ground in a liquid at a concentration of 1-90% m / m, and stabilize the suspension until a stable colloidal suspension is obtained; The following steps are performed: placing the suspension and grinding balls having a selected diameter of 5 μm to 1.3 mm into the grinding chamber; adjusting the mill rotation speed between 500 and 4500 rpm; and grinding the particles at a temperature of less than 60°C; The steps involve: feeding particles smaller than 40 micrometers into a jet mill or steam mill at a superheated temperature; adjusting the speed of the air classifier between 1,000 and 25,000 rpm; adjusting the compressed steam pressure between 10 and 100 bar; and adjusting the temperature between 230 and 360°C. The steps include adjusting the grinding conditions selected from; The steps include grinding the particles until a desired particle size distribution profile is obtained. Includes.

[0108] The reduction in average particle size achieved through pretreatment, as demonstrated above, is particularly useful for improving the performance of subsequent grinding processes in high-energy mills, as demonstrated in Examples 1-4 and 7, or in the steam mill grinding process described in Example 6 below.

[0109] In one embodiment, this method involves wet milling in a high-energy mill, making it possible to obtain, for the first time on an industrial scale, niobium pentoxide particles mainly or entirely within the nanometer particle size range. In embodiments in which grinding is performed in a high-energy wet mill, stabilizing the colloidal suspension to be placed in the grinding chamber of the high-energy mill is a very important step, which is selected from adjusting the pH of the polar liquid medium in the range of 2 to 13 and optionally adding a surfactant; or adding a surfactant to a non-polar liquid medium.

[0110] In one embodiment, by adjusting certain parameters including rotation time, pH, and temperature, a mill known in the latest technology, such as a high-energy mill using yttria-stabilized zirconia spheres (ZrO2 + Y2O3), is used. In one embodiment, the grinding medium comprises zirconia balls, ZTA (alumina-reinforced zirconia or yttrium), and alumina. Preferably, zirconium spheres stabilized with 5% m / m yttria are used.

[0111] In another embodiment, the method involves grinding with a jet mill (steam mill) having superheated steam, to which particles smaller than 40 microns are supplied, the rotation of the air classifier is adjusted between 1,000 and 25,000 rpm, the compressed steam pressure is adjusted between 10 and 100 bar, and the temperature is adjusted between 230 and 360°C.

[0112] [Examples]

[0113] The examples provided herein are intended to illustrate, but not to limit, some of the various ways in which the present invention can be carried out.

[0114] (Example 1) - Wet grinding process of niobium pentoxide (Nb2O5) in a high-energy mill

[0115] In this embodiment, a preparation of niobium pentoxide nanoparticles was obtained by milling with adjustment of parameters including rotation speed, pH, and temperature.

[0116] Niobium pentoxide (Nb2O5) from a commercially available source, possessing high purity and having a particle size distribution of d90=68.425, d50=20.867, and d10=0.345 (μm), was supplied to a high-energy mill of the agitated medium type. The mill operated with grinding balls / spheres made of yttria-stabilized zirconia, with diameters ranging from 5 μm to 1.3 mm. In this embodiment, the size of the balls was 400 μm. Grinding conditions for the material to obtain niobium nanoparticle powder (Nb2O5) included a rotational speed of 1000 to 4500 rpm and a temperature below 40°C, maintained with the help of an external forced cooling system for the mill. After 30 to 120 minutes of operation under these conditions, a powder preparation containing niobium nanoparticles was obtained.

[0117] Efficiency was evaluated by testing various grinding conditions. Table 1 shows the test results for various milling parameters and times.

[0118] [Table 1]

[0119] The data in Table 1 shows that under conditions of a grinding time of 30 minutes, pH 6.63, volume-based sizing technique by laser scattering using the Mie model, and a temperature of 34.7°C, nanoparticles with d10 of 0.077; d50 of 0.178; and d90 of 0.402 (77 nm, 178 nm, and 402 nm, respectively) were obtained.

[0120] (Example 2)-Particle size measurement

[0121] The particle size distribution was measured by laser scattering using a FRITSCH brand Analysette 22 NanoTecplus. As shown in Figure 1, the niobium nanoparticle preparations of the present invention have a particle size distribution that is entirely within the nanoparticle range. Figure 1 shows the particle size distribution, i.e., the equivalent diameter of the particles in nanometers (horizontal axis), the relative fraction of nanoparticles (vertical axis on the left), and the cumulative fraction (vertical axis on the right). The figure shows that the niobium nanoparticles of this embodiment of the present invention have an equivalent diameter of 10 to 1000 nanometers (nm), with 90% being 10 to 400 nm, 80% being 10 to 300 nm, and 50% being 10 to 178 nm.

[0122] (Example 3) - Stable colloidal suspension - Stability test of niobium particles in aqueous solution as a function of pH

[0123] A stable colloidal suspension was obtained using the nanoparticle preparation obtained according to Example 1, and stabilization tests were performed as a function of pH. Figure 2 shows the results obtained in numbered test tubes for various tested pH values: 2, 4, 9, and 12. As shown in Figure 2, the results indicate that the stability of niobium nanoparticles is strongly dependent on the pH of the medium, and that the particles reached the highest level of instability at pH 4. It was also observed that virtually 100% of the particles precipitated at pH 4, as the supernatant liquid in the test tube did not contain any solid particles of a size that could be affected by visible light from the environment. The supernatant liquid has the typical translucency of the aqueous solution used. Accumulation of niobium particles was also observed at the bottom of the test tube at pH 4, indicating the height of the precipitate formed by the particles. At pH 9, the particles under that condition were less prone to precipitation and showed higher stability.

[0124] (Example 4) - Liquid composition containing niobium nanoparticles - Stability / shelf life test

[0125] The nanoparticle preparations according to Examples 1 and 2 were subjected to stability tests as a function of time (storage period). Figure 3 shows the results of the tests, indicating that after a 6-hour turbidimetric test using a TURBISCAN apparatus, the particles at pH 9 remained stable and did not form precipitates. This behavior is characteristic of stable nanometer particles.

[0126] (Example 5) - Wet grinding process of niobium pentoxide (Nb2O5) in a high-energy mill

[0127] Micrometer niobium pentoxide particles were supplied to a Labstar LS01 ball mill (Netzsch). The process involved high-energy wet milling. The particle suspension was 17.7% m and consisted of approximately 3500 g of mill-Q water + 10 M NaOH and 750 g of solid sample prepared and stabilized in a mill mixing tank at pH 9 and titrated with 10 M NaOH. The grinding balls used were yttria-stabilized zirconia with a diameter of 400 μm. The grinding chamber was filled to 80% vol, and the suspension temperature was less than 40°C. The mill rotation speed was set to 3000 rpm, and grinding was performed for 8 hours. 10 M NaOH was added during milling to stabilize the suspension at pH 9, and samples were taken occasionally to measure the particle size.

[0128] Particle measurements were performed using a Fritsch instrument, an Analysette 22 model equipped with a wet particle size analyzer as an accessory. Particle size distribution was measured by static light scattering. The analytical medium was distilled water. A constant volume suspension of 17.7% m was analyzed 10 times using the instrument during the milling process. The results in Table 2 show the measurements (average of 10 measurements) and DTP (particle size distribution) obtained at each grinding time under the conditions described above.

[0129] [Table 2]

[0130] The particle size distribution curves as functions of frequency and cumulative volume are shown in Figures 4 and 5.

[0131] Figure 4 shows the particle size distribution of ground niobium pentoxide as a function of grinding time in a high-energy mill (sampling frequency). The equivalent particle diameter in nm is shown on the x-axis, and the frequency in % is shown on the y-axis.

[0132] Figure 5 shows the particle size distribution as a function of cumulative volume of the pulverized niobium pentoxide sample. The equivalent diameter of the particles at m is shown on the x-axis, and the cumulative volume at % is shown on the y-axis.

[0133] (Example 6) - Grinding of niobium pentoxide by jet mill

[0134] In the embodiments of the present invention, niobium pentoxide particles were pre-ground using a jet mill to improve the performance of the subsequent grinding process until a complete particle size distribution (d99) within the nanometer range was achieved.

[0135] Input particle size distribution profiles were d90% 69.4μm; d50% 40.6μm; and d10% 13.4μm, relative humidity 0.85% (Sartorius -105℃ for 20 minutes), and bulk density 1.62 g / cm³. 3 Niobium pentoxide samples containing the specified compound were subjected to various grinding conditions using a jet mill, as summarized in Table 3.

[0136] [Table 3-1] [Table 3-2]

[0137] Figure 6 shows the cumulative particle distribution profile of Nb2O5 in alcohol as a dispersant in a jet mill (Product 1 in Table 3 above). The equivalent diameter in microns is shown on the x-axis, the volume % is shown on the left y-axis, and the cumulative volume % is shown on the right y-axis. For this sample, the residual weight was 1.14%, and the specific surface area was 1.536 m². 2The concentration is 0.0020% per g. The particle distribution profile is dD90=31.1μm;D50=11.4μm;d10=1.41μm.

[0138] Figure 7 shows the cumulative particle distribution profile of Nb2O5 in alcohol as a dispersant in a jet mill (product 3 in Table 3 above). The equivalent diameter in microns is shown on the x-axis, the volume % is shown on the left y-axis, and the cumulative volume % is shown on the right y-axis. In this sample, the residual weight is 0.68%, and the specific surface area is 1.063 m². 2 The concentration is 0.0081% per g. The particle distribution profile is dD90=22.3μm;D50=8.88μm;d10=2.77μm.

[0139] The reduction in average particle size demonstrated above is particularly useful for improving the performance of subsequent high-energy mill grinding processes, as demonstrated in Examples 1-4, or the grinding process described in Example 7 below.

[0140] (Example 7) - Grinding of niobium pentoxide by steam mill

[0141] In this embodiment, Nb2O5 particles having the distribution profile dD90=22.3μm;D50=8.88μm;d10=2.77μm as shown in Figure 7 (Example 6) were supplied to the steam mill.

[0142] Next, the rotation speed of the air classifier was adjusted to 20,000 rpm, and the compressed steam pressure was adjusted to 50 bar. The temperature of the superheated fluid was 280°C.

[0143] After operation under these conditions, particle size distribution profiles similar to those obtained in Examples 1-2 and Figure 1 were obtained.

[0144] (Example 8) - Preparation of niobium pentoxide (Nb2O5) nanoparticles with high purity and specified particle size distribution

[0145] In the embodiments of the present invention, several embodiments of niobium pentoxide nanoparticle preparations having a purity of over 99% were obtained. Commercially available niobium pentoxide having the particle size distribution shown in Table 4 was pre-ground in a liquid medium and at a pH adjusted to 6.6 in a high-energy mill containing yttria-stabilized zirconia spheres having a diameter of 400 μm. The mill rotation speed was set to 3500 rpm, and particle grinding was performed at a temperature of less than 40°C. Table 4 shows the particle size distribution (DTP) of the input niobium pentoxide (commercially available) and the product niobium pentoxide in the pre-ground step.

[0146] [Table 4]

[0147] Figure 8 shows curves corresponding to the particle size distribution profiles of a commercially available product containing niobium pentoxide (curve A = input) and a niobium pentoxide preparation after pre-grinding (curve B). The equivalent particle diameter in micrometers is shown on the x-axis, and the cumulative volume in percent is shown on the y-axis.

[0148] Figure 9 shows curves corresponding to the particle size distribution profiles of a commercially available product containing niobium pentoxide (curve A = input) and a niobium pentoxide preparation after pre-grinding (curve B). The equivalent diameter of the particles in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis. The data shows that the pre-grinding step makes it possible to obtain a preparation containing niobium pentoxide fine particles having particles of 1 to 40 micrometers.

[0149] The average specific surface area S(m²) of the particles after the preliminary grinding step. 2 ( / g) is 0.32m 2 It was / g.

[0150] In one embodiment, the particles after preliminary grinding were then fed into a high-energy mill, and the same conditions as described in Example 5 were applied, but 200 μm Zr spheres were used, and milling was performed for different times until each nanoparticle preparation was obtained. Three different nanoparticle preparations were obtained, each having the specified particle size distribution shown in Table 5.

[0151] [Table 5]

[0152] Figure 10 shows a curve (curve C) corresponding to the particle size distribution profile of a preparation of niobium pentoxide nanoparticles having particles between 74 and 747 nm, all within the (d99.99) nanometer range. The equivalent diameter of the particles in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0153] Figure 11 shows a curve (curve D) corresponding to the particle size distribution profile of a preparation of niobium pentoxide nanoparticles having particles ranging from 20 to 206 nm, all within the (d99.99) nanometer range. The equivalent diameter of the particles in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0154] Figure 12 shows a curve (curve E) corresponding to the particle size distribution profile of a preparation of niobium pentoxide nanoparticles having particles between 8 and 89 nm, all within the (d99.99) nanometer range. The equivalent diameter of the particles in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0155] Figure 13 shows a single graph of curves corresponding to the particle size distribution profiles (curves C, D, and E) of three different preparations of niobium pentoxide after preliminary grinding, as shown in Figures 10-12. The equivalent particle diameter in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0156] Figure 14 shows a single graph representing the particle size distribution profiles (curves C, D, and E) of three different preparations of niobium pentoxide after pre-grinding. The equivalent particle diameter in micrometers is shown on the x-axis, and the frequency in percent is shown on the y-axis.

[0157] The nanoparticle preparations of this embodiment of the present invention have a very large specific surface area, which allows them to be used in a very wide range of applications. Table 6 shows the average specific surface area data of the niobium pentoxide nanoparticle preparations.

[0158] [Table 6]

[0159] In a portion of the prepared product E, 90m 2 Niobium pentoxide nanoparticles exceeding 1 / g were obtained, with one fraction containing 148.2m 2 The result was / g, which is noteworthy as it far exceeds the value that had never been achieved with prior art.

[0160] Those skilled in the art will know that by using a classifier such as an air classifier or an ultracentrifuge, it is possible to separate different particle size fractions of each preparation, thereby obtaining a narrower particle size distribution profile curve compared to those illustrated above.

[0161] (Example 9) Nanoparticle preparations obtained from a combination of perfectly nanometer-sized preparations of niobium pentoxide (Nb2O5)

[0162] In the embodiments of the present invention, various nanoparticle preparations were obtained by combining the two nanoparticle preparations (preparations C and E) illustrated in Example 8 above.

[0163] In one embodiment, a 1:1 mixture of preparation C and preparation E of Example 8 was obtained by simple homogenization.

[0164] In another embodiment, a 1:10 mixture of preparation C and preparation E of Example 8 was obtained by simple homogenization.

[0165] In another embodiment, a 1:1 mixture of preparation D and preparation B (after pre-grinding) of Example 8 was obtained by simple homogenization.

[0166] The combination of larger particles (preparation B or C) and smaller nanoparticles (preparation D or E) results in varying degrees of packing, porosity, flowability, and different behavior in subsequent applications such as sintering, dispersions in viscous liquids, and other applications, thus enabling the tuning of the rheology of the resulting preparation.

[0167] Those skilled in the art will appreciate the knowledge presented herein and will be able to reproduce the present invention in the presented form and in other variations and alternative forms, as covered by the following claims.

Claims

1. A preparation of niobium pentoxide nanoparticles, characterized by containing 95 wt% or more of niobium pentoxide particles, wherein the particle size distribution profile is d10: 14 to 110 nm; d50: 29 to 243 nm; and d90: 89 to 747 nm. , preparation of the above niobium pentoxide nanoparticles.

2. The nanoparticle preparation according to claim 1, characterized in that 90% to 99% of the particles (d90 to d99) are within a particle size range of 5 to 1000 nanometers (nm).

3. A preparation of nanoparticles according to claim 1 or 2, characterized in that it contains niobium pentoxide particles with a content of 99 wt% or more.

4. A nanoparticle preparation according to any one of claims 1 to 3, characterized in that the particle size distribution profile is d10 70-100 nm; d50 170-240 nm; d90 400-580 nm.

5. A nanoparticle preparation according to any one of claims 1 to 3, characterized in that the particle size distribution profile is d50 10 to 178 nm; d80 10 to 300 nm; d90 10 to 400 nm.

6. A nanoparticle preparation according to any one of claims 1 to 3, characterized in that 90% to 99% of the particles (d90 to d99) are within a particle size range of 100 to 1000 nm.

7. A nanoparticle preparation according to any one of claims 1 to 3, characterized in that 90% to 99% of the particles (d90 to d99) are within a particle size range of 5 to 100 nm.

8. The nanoparticle preparation according to claim 7, characterized in that the particle size distribution profile is d10: 9 to 27 nm; d50: 16 to 67 nm; d90: 33 to 94 nm.

9. Average specific surface area is 0.5 to 150 m² ２ A preparation of nanoparticles according to any one of claims 1 to 3, characterized in that it is / g.

10. Average specific surface area is 40-70 m² ２ The nanoparticle preparation according to claim 9, characterized in that it is / g.

11. - The step of supplying niobium pentoxide particles to a grinding device selected from a high-energy ball mill and a steam jet mill; In a high-energy ball mill: The particles to be ground are suspended in a liquid at a particle concentration of 1 to 90% by mass relative to the mass of the particles and the liquid, and the suspension is stabilized until a stable colloidal suspension is obtained; the suspension and grinding balls having a selected diameter of 5 μm to 1.3 mm are placed in the grinding chamber; the mill rotation speed is adjusted between 500 and 4500 rpm; the particles are ground at a temperature of less than 60°C; or - In a steam jet mill, feed particles smaller than 40 micrometers; adjust the speed of the air classifier between 1,000 and 25,000 rpm; adjust the compressed steam pressure between 10 and 100 bar; and adjust the temperature between 230 and 360°C. The steps include adjusting the grinding conditions selected from one of the following: - A step of grinding the particles until the desired particle size distribution profile is obtained. A method for obtaining niobium pentoxide nanoparticles containing [the specified substance].

12. The method according to claim 11, characterized in that the colloidal suspension is stabilized by adjusting the pH of a polar liquid medium to a range of 2 to 13 and optionally adding a surfactant, or by adding a surfactant to a non-polar liquid medium.

13. The method according to claim 11 or 12, further comprising a pre-grinding step of niobium pentoxide particles before the step of supplying them to a grinding device, characterized in that the pre-grinding is carried out until an average particle size of less than 40 micrometers is reached.

14. The method according to claim 13, characterized in that the preliminary grinding is performed in a ball mill, a disc mill, a high-energy mill, or a jet mill.

15. - Micrometer-sized niobium pentoxide (Nb) is milled into a high-energy ball mill. ２ O ５ ) the step of supplying particles; - A step of supplying liquid to the mill and adjusting the pH to a range of 5 to 10; - A step of supplying balls having a selected diameter of 50 μm to 400 μm to the mill; - The step of adjusting the mill rotation speed between 2000 and 4000 rpm; - A step of grinding the particles at a temperature of less than 60°C until the desired particle size profile is obtained. A method according to claim 11 or 12, characterized by including the following:

16. The method according to claim 11, characterized in that the high-energy ball mill is of the agitated medium type, the spheres are selected from zirconia, silicon carbide, and alumina, and the spheres are optionally stabilized with yttria, niobium pentoxide, or a combination thereof.

17. The method according to claim 11 or 13, characterized in that the steam jet mill is adjusted by the following parameters: rotation of an air classifier at 20,000 rpm; compressed vapor pressure at 50 bar; and superheated fluid temperature at 280°C.

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