MANGANESE FERRITE MAGNETIC NANOPARTICLE, PREPARATION METHOD AND APPLICATION THEREOF

Abstract

The present invention relates to the technical field of anti-icing materials, and in particular to a manganese ferrite magnetic nanoparticle, preparation method and application thereof. The manganese ferrite magnetic nanoparticle prepared by the present invention is LaxCaySrzMnO3, wherein X=0.1-0.7, Y=0.1-0.35, and Z=0-0.16; and is prepared from the following materials, comprising, in parts by weight: 10-70 parts of lanthanum nitrate, 10-35 parts of calcium nitrate, 2-10 parts of strontium nitrate, and 30-50 parts of manganese nitrate.

Claims

1. A preparation method for a manganese ferrite magnetic nanoparticle, wherein the method is a hydrothermal method performed in a hydrothermal autoclave reactor, comprising the following steps: S01: adding the following materials in parts by weight into purified water and stirring to obtain a reaction solution: 30-60 parts of lanthanum nitrate, 10-25 parts of calcium nitrate, 2-5 parts of strontium nitrate, and 30-40 parts of manganese nitrate; adjusting pH of the reaction solution to 8-10, and then subjecting the reaction solution to ultrasonic treatment; S02: transferring the reaction solution obtained in S01 into a hydrothermal autoclave reactor and heating at a temperature of 200-300 C. for 12-24 hours; S03: drying the resulting product, then annealing at a temperature of 900-1000 C. for 10-15 hours, followed by grinding to obtain a crude manganese ferrite magnetic particle product; S04: modifying the crude manganese ferrite magnetic particle product to obtain the manganese ferrite magnetic nanoparticle; the modification comprises modification with oleic acid and/or fluorosilane; the molecular formula of the manganese ferrite magnetic nanoparticle is La.sub.xCa.sub.yMnO.sub.3, wherein X=0.3, Y=0.1.

2. The preparation method according to claim 1, wherein the modification in S04 comprises adding the crude manganese ferrite magnetic particle product to a oleic acid solution, a fluorosilane solution, or a oleic acid solution followed by a fluorosilane solution, and stirring at a temperature of 60-90 C.

3. The preparation method according to claim 1, wherein a particle size of the manganese ferrite magnetic nanoparticle after modification in S04 is in the range of 250-300 nm.

4. An application of the manganese ferrite magnetic nanoparticle prepared by the preparation method according to claim 1 in the preparation of a low-Curie-point anti-icing coating.

Description

DESCRIPTION OF DRAWINGS

[0030] To make the embodiments of the present invention or the technical solutions in the prior art clearer, the drawings required to be used in the description of the embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale. It is obvious that the drawings described below are some embodiments of the present invention, and that other drawings can be obtained from these drawings for those of ordinary skill in the art without making inventive effort.

[0031] FIG. 1 is an SEM image (scale bar: 1 m) of the manganese ferrite magnetic nanoparticle (without oleic acid modification) prepared in one embodiment of the present invention.

[0032] FIG. 2 is an SEM image (scale bar: 300 nm) of the manganese ferrite magnetic nanoparticle (with oleic acid modification) prepared in one embodiment of the present invention.

[0033] FIG. 3 is an elemental composition analysis diagram of the manganese ferrite magnetic nanoparticle prepared in one embodiment of the present invention.

[0034] FIG. 4 shows control samples of manganese ferrite magnetic nanoparticles prepared in one embodiment of the present invention, where A represents La.sub.0.67Ca.sub.0.33MnO.sub.3, B represents La.sub.0.7Ca.sub.0.25Sr.sub.0.05MnO.sub.3, and C represents La.sub.0.6Ca.sub.0.35Sr.sub.0.15MnO.sub.3.

[0035] FIG. 5 shows control samples of manganese ferrite magnetic nanoparticles prepared in one embodiment of the present invention, where A represents La.sub.0.67Ca.sub.0.33MnO.sub.3, B represents La.sub.0.6Ca.sub.0.35MnO.sub.3, and C represents La.sub.0.1Ca.sub.0.1MnO.sub.3.

[0036] FIG. 6 is an EDS diagram of the manganese ferrite magnetic nanoparticle prepared in one embodiment of the present invention using different modification methods, where A represents modification with OA (oleic acid), and B represents modification with OA+FAS (fluorosilane).

[0037] FIG. 7 shows the Curie temperature test results of the manganese ferrite magnetic nanoparticle (with oleic acid and fluorosilane modification) prepared in one embodiment of the present invention.

[0038] FIG. 8 shows the calculated magnetic entropy change of the manganese ferrite magnetic nanoparticle (with oleic acid and fluorosilane modification) prepared in one embodiment of the present invention.

[0039] FIG. 9 shows the thermogravimetric analysis results of the manganese ferrite magnetic nanoparticle (with oleic acid and fluorosilane modification) prepared in one embodiment of the present invention.

[0040] FIG. 10 shows the anti-frosting experiment results of the manganese ferrite magnetic nanoparticle prepared in one embodiment of the present invention, where A is the experimental sample, and B is the control sample.

[0041] FIG. 11 shows the core loss measurement results of the manganese ferrite magnetic nanoparticle prepared in one embodiment of the present invention.

DETAILED DESCRIPTION

[0042] To make the objective, the technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in combination with drawings. It is obvious that the described embodiments are some of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making inventive effort shall belong to the protection scope of the present invention.

[0043] As used herein, and/or includes any and all combinations of one or more of the items listed.

[0044] As used herein, multiple means two or more, i.e., it includes two, three, four, five, etc.

[0045] It should be noted that the term include, comprise or any variant thereof is intended to encompass nonexclusive inclusion so that a process, method, article or device including a series of elements includes not only those elements but also other elements which have been not listed definitely or an element(s) inherent to the process, method, article or device. Moreover, the expression comprising a (n) . . . in which an element is defined will not preclude presence of an additional identical element(s) in a process, method, article or device comprising the defined element(s) unless further defined.

[0046] As used herein, the term about, typically means+/5% of the stated value, more typically +/4% of the stated value, more typically +/3% of the stated value, more typically, +/2% of the stated value, even more typically +/1% of the stated value, and even more typically +/0.5% of the stated value.

[0047] Throughout this application, embodiments of this invention may be presented with reference to a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc.; as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Embodiment 1

[0048] This embodiment provides an exemplary preparation method for a manganese ferrite magnetic nanoparticle.

Preparation Method:

[0049] S01: adding the following materials in parts by weight into purified water and stirring for 1 hour to obtain a reaction solution: 30 parts of lanthanum nitrate, 10 parts of calcium nitrate, 2 parts of strontium nitrate, and 40 parts of manganese nitrate; adjusting pH of the reaction solution to 9, and then subjecting the reaction solution to ultrasonic treatment for 1 hour; [0050] S02: transferring the reaction solution obtained in S01 into a hydrothermal autoclave reactor and heating at 270 C. for 24 hours; [0051] S03: drying the resulting product, annealing at 1000 C. for 10 hours, and then grinding to obtain a crude manganese ferrite magnetic particle product; [0052] S04: adding the crude manganese ferrite magnetic particle product obtained in S03 into an ethanol or methanol solution and stirring to obtain a first product, adding the first product to a 5-25 wt. % oleic acid (OA) solution followed by a 3-20 wt. % fluorosilane (FAS) solution to obtain a mixture, continuing stirring and heating the mixture at 60-90 C. to remove the ethanol or methanol, and then filtering and drying to obtain the manganese ferrite magnetic nanoparticle.

[0053] The molecular formula of the manganese ferrite magnetic nanoparticle obtained in this embodiment is La.sub.0.3Ca.sub.0.1MnO.sub.3. The crude particles have a particle size of approximately 50 nm. After modification, the particle size is approximately 300 nm. The overall morphology is fine and granular. Morphological characteristics are shown in FIG. 1 and FIG. 2, and elemental composition analysis by energy-dispersive spectroscopy mapping is shown in FIG. 3.

Embodiment 2

[0054] This embodiment provides control preparation examples based on the Embodiment 1.

[0055] (1) Based on the method described in Embodiment 1, adjusting the material composition and omitting the annealing step results in the formation of rod-like structures only.

TABLE-US-00001 TABLE 1 Nanoparticles Prepared Using Different Material Ratios Material Ratio Molecular Formula (by weight) Morphology Particle Size La.sub.0.67Ca.sub.0.33MnO.sub.3 67 parts of Primarily Approximately lanthanum granular 50 nm nitrate, with a few 33 parts of nanorods calcium (FIG. 4A) nitrate, 0 parts of strontium nitrate, 40 parts of manganese nitrate La.sub.0.7Ca.sub.0.25Sr.sub.0.05MnO.sub.3 70 parts of Predominantly Approximately lanthanum nanorods 600 nm nitrate, (FIG. 4B) 25 parts of calcium nitrate, 5 parts of strontium nitrate, 40 parts of manganese nitrate La.sub.0.6Ca.sub.0.35Sr.sub.0.15MnO.sub.3 60 parts of A few Approximately lanthanum nanorods 400 nm nitrate, (FIG. 4C) 35 parts of calcium nitrate, 15 parts of strontium nitrate, 40 parts of manganese nitrate

[0056] (2) Based on the method described in Embodiment 1, by adjusting the material ratios and applying different annealing parameters, rod-like and granular structures are obtained.

TABLE-US-00002 Material Ratio Annealing Molecular Formula (by weight) Parameters Morphology Particle Size La.sub.0.67Ca.sub.0.33MnO.sub.3 67 parts of 900 C. for Primarily 200-500 nm lanthanum 10 h cubic nitrate, particles 33 parts with a few of calcium nanorods and nitrate, agglomeration 0 parts of (FIG. 5A) strontium nitrate, 40 parts of manganese nitrate La.sub.0.6Ca.sub.0.35Sr.sub.0.15MnO.sub.3 60 parts of 900 C. for Predominantly 600-800 nm lanthanum 10 h nanorods nitrate, (FIG. 5B) 35 parts of calcium nitrate, 15 parts of strontium nitrate, 40 parts of manganese nitrate La.sub.0.1Ca.sub.0.1MnO.sub.3 10 parts of 1000 C. for A few Approximately lanthanum 10 h nanorods 150 nm nitrate, with 10 parts agglomeration of calcium (FIG. 5C) nitrate, 0 parts of strontium nitrate, 40 parts of manganese nitrate

[0057] (3) Based on the La.sub.0.3Ca.sub.0.1MnO.sub.3 nanoparticles prepared in Embodiment 1, different modification methods are applied, including modification with oleic acid (OA) alone and oleic acid followed by fluorosilane (FAS). As shown in FIG. 6, nanoparticles with a particle size of approximately 300 nm and a fine granular morphology are obtained using both modification methods.

Embodiment 3

[0058] This embodiment provides performance validation of the modified manganese ferrite magnetic nanoparticle prepared in Embodiment 1.

3.1 Curie Temperature Test

[0059] Method: A SQUID-VSM magnetic property measurement system (Quantum Design, USA) is used. The system is based on Superconducting Quantum Interference Device (SQUID) detection technology. By applying DC or AC magnetic fields to the magnetic material, it generates DC (AC) magnetization intensity versus temperature (field strength) curves for the test sample, namely the M-H and M-T curves. A linear fit is performed on the M-T curve, and the temperature point corresponding to the point of maximum slope is identified as the Curie temperature point. The procedure is as follows:

[0060] (1) Weigh the mass of the magnetic powder sample.

[0061] (2) Load the magnetic powder sample into the sample rod and place the sample rod into the measurement chamber.

[0062] (3) Flush the chamber with helium gas (default procedure: flush three times), followed by evacuation.

[0063] (4) Set the temperature range (100 K-400 K) and the magnetic field strength (1.5 T); scan the signal-position curve to locate the sample.

[0064] (5) Apply a DC or AC magnetic field to the magnetic powder sample to obtain DC (AC) magnetization intensity versus temperature (field strength) curves for the test sample, namely the M-T curves. A linear fit is performed on the M-T curve, and the temperature point of maximum slope is identified as the Curie temperature point.

[0065] Result: The Curie temperature of La.sub.0.3Ca.sub.0.1MnO.sub.3 nanoparticles modified with oleic acid and fluorosilane is measured to be approximately 264.50 K, corresponding to a low temperature of approximately 8.65 C. This satisfies the requirement for a Curie temperature close to 0 C. See FIG. 7.

[0066] Based on the M-T curve results, the magnetic entropy change at different temperatures is calculated using established formulas referenced from publicly available literature to evaluate the heat generation efficiency. As shown in FIG. 8, the maximum magnetic entropy change near the Curie temperature is 1.18 J/kg.Math.K. This value compares favorably with the reported maximum values in the range of 0.64-1.25 J/kg.Math.K in the publicly available literature, demonstrating superior heat generation performance. The reference publication is Observation of the magnetic entropy change in Zn doped MnFe.sub.2O.sub.4 common ceramic: Be cool being environmental friendly.

3.2 Thermogravimetric Analysis (TGA)

[0067] Method: Thermogravimetric analysis is performed using a TGA analyzer. Under programmed temperature increase (from 0 C. to 1200 C., over the course of one hour), the mass change of the magnetic powder is measured as a function of temperature or time, and corresponding thermal absorption and release are recorded.

[0068] Result: Thermogravimetric analysis of the La.sub.0.3Ca.sub.0.1MnO.sub.3 nanoparticles modified with oleic acid and fluorosilane is conducted, as shown in FIG. 9. The results demonstrate that the nanoparticles maintain mass stability within the temperature range of 800-900 C.

Embodiment 4

[0069] This embodiment provides the anti-icing and anti-frosting performance test of the modified manganese ferrite magnetic nanoparticle prepared in Embodiment 1.

[0070] Method: A semiconductor refrigeration platform (LTD1-350) is used. The sample is placed on the semiconductor refrigeration platform for a frosting experiment conducted at 8 C. The La.sub.0.3Ca.sub.0.1MnO.sub.3 nanoparticles, modified with oleic acid and fluorosilane prepared in Embodiment 1, are mixed with ethanol and coated onto the surface of a superhydrophobic porous structured sample. The sample is placed on a magnet generating a relatively weak magnetic field of 2600 Gauss. The darker region represents the oxidized porous sample coated with the magnetic nanoparticles, while the white region represents the uncoated oxidized porous sample.

[0071] As shown in FIG. 10, over time, the darker region exhibits delayed frost formation, demonstrating the enhanced anti-frosting performance of the superhydrophobic porous structure. The results confirm that the magnetic nanoparticles prepared in the present invention can effectively prevent frosting. In contrast, the uncoated substrate sample becomes fully frosted within 5 minutes, while the sample coated with magnetic nanoparticles exhibits delayed frosting for up to 30 minutes.

[0072] It should be understood that the superhydrophobic porous structured sample used in this embodiment may be prepared by any known method disclosed in publicly available literature.

Embodiment 5

[0073] This embodiment provides the core loss testing of the modified manganese ferrite magnetic nanoparticle prepared in Embodiment 1.

[0074] Method: A SQUID-VSM magnetic property measurement system (Quantum Design, USA) is used. The procedure is as follows:

[0075] (1) Weigh the mass of the magnetic powder sample.

[0076] (2) Load the magnetic powder sample into the sample rod and place the sample rod into the measurement chamber.

[0077] (3) Flush the chamber with helium gas (default procedure: flush three times), followed by evacuation.

[0078] (4) Set the temperature range (100 K-400 K) and the magnetic field strength (1.5 T); scan the signal-position curve to locate the sample.

[0079] (5) Apply a DC or AC magnetic field to the magnetic powder sample to obtain DC (AC) magnetization intensity versus temperature (field strength) curves for the test sample, namely M-H curves. For the M-H curves measured at various temperatures, the value of the magnetic field (H) when magnetization (M) equals 0 is calculated. A large absolute value of H indicates high coercivity, which increases susceptibility to heat generation under alternating magnetic fields at room temperature during power transmission, thereby leading to core loss. Conversely, smaller H values or M-H curves closer to the origin indicate lower coercivity and good paramagnetic behavior, resulting in minimal heat generation and low core loss under alternating magnetic fields at room temperature.

[0080] Result: The La.sub.0.3Ca.sub.0.1MnO.sub.3 nanoparticles modified with oleic acid and fluorosilane exhibit coercivity values of 0.4 Oe at all tested temperatures (260 K, 270 K, 280 K, 290 K, and 300 K), with negligible remanent magnetization (close to 0). These results confirm that the nanoparticle is a soft magnetic material and does not cause magnetic hysteresis losses or heat generation under transmission-line operating conditions. Thus, it is suitable for anti-icing or anti-frosting applications in power transmission lines. See FIG. 11.

[0081] The embodiments of the present invention are described above with reference to the accompanying drawings, but the present invention is not limited to the aforementioned specific embodiments. The aforementioned embodiments are merely illustrative and not limiting. For those of ordinary skill in the art, many forms can be made under the teaching of present invention without departing from the spirit of the present invention and the scope of the claims, all of which shall fall within the protection scope of the present invention.