MODIFIED NANOCRYSTALLINE STRIP, PREPARATION METHOD THEREFOR, AND APPLICATION THEREOF
20230332329 · 2023-10-19
Assignee
Inventors
Cpc classification
International classification
C30B33/00
CHEMISTRY; METALLURGY
Abstract
Disclosed are a modified nanocrystalline strip, a preparation method therefor, and an application thereof. The preparation method comprises: performing rolling treatment on a nanocrystalline strip with a double-sided adhesive adhered on one side to obtain a micro-crushed nanocrystalline strip; performing acid etching surface treatment on the obtained micro-crushed nanocrystalline strip; performing alkaline washing surface treatment on the nanocrystalline strip subjected to acid etching surface treatment; sequentially washing with water and washing with alcohol the nanocrystalline strip obtained by the alkaline washing surface treatment, and then drying same; and performing micro-oxidation treatment on the dried nanocrystalline strip to obtain a modified nanocrystalline strip.
Claims
1. A method for preparing a modified nanocrystalline strip, comprising: (1) performing roller-pressing treatment on a nanocrystalline strip with a double-sided tape adhered to one side to obtain a micro-crushed nanocrystalline strip; (2) performing acid corroding surface treatment on the micro-crushed nanocrystalline strip obtained in step (1); (3) performing alkali washing surface treatment on the nanocrystalline strip after the acid corroding surface treatment in step (2); (4) performing water washing, alcohol washing and drying in sequence on the nanocrystalline strip obtained through the alkali washing surface treatment in step (3); and (5) performing micro-oxidation treatment on the dried nanocrystalline strip in step (4) to obtain the modified nanocrystalline strip.
2. The preparation method according to claim 1, wherein the nanocrystalline strip comprises, in mass percent, 73.5 wt % Fe, 13.5 wt % Si, 9 wt % B, 3 wt % Nb and 1 wt % Cu.
3. The preparation method according to claim 1, wherein the roller-pressing in step (1) has a pressure of 60-70 kg.
4. The preparation method according to claim 1, wherein the roller-pressing in step (1) is performed for 1-5 times; optionally, the acid corroding surface treatment in step (2) comprises: coating an acidic solution on the surface of the micro-crushed nanocrystalline strip for surface acid treatment, and after the treatment is completed, washing the micro-crushed nanocrystalline strip with deionized water; optionally, the acidic solution is a hydrochloric acid solution having a mass fraction of 0.5-1.2 wt %; optionally, the surface acid treatment is performed for 3-8 min
5. The preparation method according to claim 1, wherein the alkali washing surface treatment in step (3) comprises: coating an alkaline solution on the surface of the nanocrystalline strip after the acid corroding surface treatment for surface alkali treatment, and after the treatment is completed, washing the micro-crushed nanocrystalline strip with deionized water; optionally, the alkaline solution comprises any one or a combination of at least two of a sodium bicarbonate solution, a potassium hydroxide solution or a sodium hydroxide solution, optionally a sodium hydroxide solution; optionally, the sodium hydroxide solution has a mass fraction of 0.5-2 wt %; optionally, the surface alkali treatment is performed for 5-10 min.
6. The preparation method according to claim 1, wherein the water washing in step (4) is performed for at least three times; optionally, the alcohol washing in step (4) is to wash the strip at least three times with absolute ethanol; optionally, the micro-oxidation treatment in step (5) is performed in an oxygen atmosphere having an oxygen concentration of ≥85 vol %; optionally, the micro-oxidation treatment in step (5) is performed at 60-85° C.; optionally, the micro-oxidation treatment in step (5) is performed for 15-30 min.
7. The preparation method according to claim 1, comprising: (1) performing roller-pressing treatment on a nanocrystalline strip with a double-sided tape adhered to one side to obtain a micro-crushed nanocrystalline strip, wherein the nanocrystalline strip comprises, in mass percent, 73.5 wt % Fe, 13.5 wt % Si, 9 wt % B, 3 wt % Nb and 1 wt % Cu; (2) performing acid corroding surface treatment on the micro-crushed nanocrystalline strip obtained in step (1): coating a hydrochloric acid solution having a mass fraction of 0.5-1.2 wt % on the surface of the micro-crushed nanocrystalline strip for surface acid treatment for 3-8 min, and after the treatment is completed, washing the micro-crushed nanocrystalline strip with deionized water; (3) performing alkali washing surface treatment on the nanocrystalline strip after the acid corroding surface treatment in step (2): coating a sodium hydroxide solution having a mass fraction of 0.5-2 wt % on the surface of the nanocrystalline strip after the acid corroding surface treatment for surface alkali treatment for 5-10 min, and after the treatment is completed, washing the micro-crushed nanocrystalline strip with deionized water; (4) performing water washing at least three times, absolute ethanol washing at least three times and drying in sequence on the nanocrystalline strip obtained through the alkali washing surface treatment in step (3); and (5) performing micro-oxidation treatment on the dried nanocrystalline strip in step (4) in an oxygen atmosphere having an oxygen concentration of ≥85 vol % for 15-30 min at 60-85° C. to obtain the modified nanocrystalline strip.
8. A modified nanocrystalline strip prepared through the method according to claim 1.
9. (canceled)
10. (canceled)
11. (canceled)
12. A method for manufacturing a nanocrystalline composite-structure magnetic sheet, which uses the modified nanocrystalline strip according to claim 8.
13. The method according to claim 12, wherein the nanocrystalline composite-structure magnetic sheet comprises a release film, a first modified nanocrystalline strip, a second modified nanocrystalline strip, a third modified nanocrystalline strip and a fourth modified nanocrystalline strip which are stacked in sequence; a double-sided tape of the first modified nanocrystalline strip is connected to the release film, and a double-sided tape between two adjacent modified nanocrystalline strips is connected to the nanocrystalline strips; the first modified nanocrystalline strip, the second modified nanocrystalline strip, the third modified nanocrystalline strip and the fourth modified nanocrystalline strip are each independently the modified nanocrystalline strip.
14. The method according to claim 12, wherein the modified nanocrystalline strip has a thickness of 18-22 μm.
15. The method according to claim 13, wherein the modified nanocrystalline strip has a thickness of 18-22 μm.
16. The method according to claim 15, wherein the double-sided tape has a thickness of 4-6 μm.
17. The method according to claim 15, wherein the first modified nanocrystalline strip has a real part of magnetic permeability of 400-500 and an imaginary part of magnetic permeability of ≤40 at a test frequency of 128 kHz.
18. The method according to claim 15, wherein the second modified nanocrystalline strip has a real part of magnetic permeability of 600-800 and an imaginary part of magnetic permeability of ≤60 at a test frequency of 128 kHz.
19. The method according to claim 15, wherein the third modified nanocrystalline strip has a real part of magnetic permeability of 1000-1400 and an imaginary part of magnetic permeability of ≤90 at a test frequency of 128 kHz.
20. The method according to claim 15, wherein the fourth modified nanocrystalline strip has a real part of magnetic permeability of 5000-10000 and an imaginary part of magnetic permeability of ≤170 at a test frequency of 128 kHz.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0064]
REFERENCE LIST
[0065] 1 release film [0066] 2 double-sided tape [0067] 3 first modified nanocrystalline strip [0068] 4 second modified nanocrystalline strip [0069] 5 third modified nanocrystalline strip [0070] 6 fourth modified nanocrystalline strip
DETAILED DESCRIPTION
[0071] Technical solutions of the present application are further described below through specific examples. Those skilled in the art are to understand that the examples described herein are used for a better understanding of the present application and are not to be construed as specific limitations to the present application.
EXAMPLE 1
[0072] This example provides a nanocrystalline composite-structure magnetic sheet as shown in
[0073] A double-sided tape 2 of the first modified nanocrystalline strip 3 is connected to the release film 1. A double-sided tape 2 between two adjacent modified nanocrystalline strips is connected to the nanocrystalline strips. The double-sided tape 2 has a thickness of 5 μm, and each modified nanocrystalline strip has a thickness of 20 μm.
[0074] The first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are each independently the modified nanocrystalline strip prepared through the following preparation method. The preparation method includes the steps described below. [0075] (1) Roller-pressing treatment was performed on a nanocrystalline strip (Fe.sub.73.5Si.sub.13.5B.sub.9Nb.sub.3Cu, where the subscript value was a percentage of each element to a total mass of the nanocrystalline strip) with the double-sided tape 2 adhered to one side to obtain a micro-crushed nanocrystalline strip, where the roller-pressing treatment had a pressure of 60 kg, and the roller-pressing was performed for three times. [0076] (2) Acid corroding surface treatment was performed on the micro-crushed nanocrystalline strip obtained in step (1): a hydrochloric acid solution having a mass fraction of 0.8 wt % was coated on the surface of the micro-crushed nanocrystalline strip for surface acid treatment for 5 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0077] (3) Alkali washing surface treatment was performed on the nanocrystalline strip after the acid corroding surface treatment in step (2): a sodium hydroxide solution having a mass fraction of 1.5 wt % was coated on the surface of the nanocrystalline strip after the acid corroding surface treatment for surface alkali treatment for 8 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0078] (4) Three times of water washing, three times of absolute ethanol washing and drying were performed in sequence on the nanocrystalline strip obtained through the alkali washing surface treatment in step (3). [0079] (5) Micro-oxidation treatment was performed on the dried nanocrystalline strip in step (4) in an oxygen atmosphere having an oxygen concentration of 95 vol % for 21 min at 75° C. to obtain the modified nanocrystalline strip.
[0080] Real parts μ′ of magnetic permeability and imaginary parts μ″ of magnetic permeability for the first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are shown in the table below.
TABLE-US-00001 Real Part μ′ of Magnetic Imaginary Part μ″ of Permeability Magnetic Permeability First modified 464.2 36.3 nanocrystalline strip Second modified 675.3 48.2 nanocrystalline strip Third modified 1275.7 82.6 nanocrystalline strip Fourth modified 9342.1 166.5 nanocrystalline strip
Comparative Example 1
[0081] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 1, except that a second modified nanocrystalline strip 4, a third modified nanocrystalline strip 5 and a fourth modified nanocrystalline strip 6 were replaced with a first modified nanocrystalline strip 3.
Comparative Example 2
[0082] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 1, except that a first modified nanocrystalline strip 3, a third modified nanocrystalline strip 5 and a fourth modified nanocrystalline strip 6 were replaced with a second modified nanocrystalline strip 4.
Comparative Example 3
[0083] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 1, except that a first modified nanocrystalline strip 3, a second modified nanocrystalline strip 4 and a fourth modified nanocrystalline strip 6 were replaced with a third modified nanocrystalline strip 5.
Comparative Example 4
[0084] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 1, except that a first modified nanocrystalline strip 3, a second modified nanocrystalline strip 4 and a third modified nanocrystalline strip 5 were replaced with a fourth modified nanocrystalline strip 6.
[0085] A charging efficiency test was performed using a P9221-EVK wireless charging system receiver apparatus manufactured by IDT, and power of the test system was 15 W, which met the Qi standard. During the test, the release film was removed, and the nanocrystalline composite-structure magnetic sheet was fixed on a back side of a coil to test electrical energy transmission efficiency. The results are shown in the table below.
TABLE-US-00002 Electrical Energy Transmission Efficiency (%) Example 1 87.1 Comparative Example 1 84.9 Comparative Example 2 85.4 Comparative Example 3 85.3 Comparative Example 4 84.2
[0086] As can be seen from the above table, the electrical energy transmission efficiency of the wireless charging system using the composite-structure magnetic sheet having gradient magnetic permeability is higher than that of the wireless charging system using the traditional composite magnetic sheet having single magnetic permeability.
EXAMPLE 2
[0087] This example provides a nanocrystalline composite-structure magnetic sheet as shown in
[0088] Real parts μ′ of magnetic permeability and imaginary parts μ″ of magnetic permeability for the first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are shown in the table below.
TABLE-US-00003 Real Part μ′ of Magnetic Imaginary Part μ″ of Permeability Magnetic Permeability First modified 492.6 38.9 nanocrystalline strip Second modified 758.2 55.7 nanocrystalline strip Third modified 1119.4 74.3 nanocrystalline strip Fourth modified 7435.9 144.1 nanocrystalline strip
[0089] The rest was the same as that in Example 1.
Comparative Example 5
[0090] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 2, except that a second modified nanocrystalline strip 4 was replaced with a first modified nanocrystalline strip 3, and a third modified nanocrystalline strip 5 and a fourth modified nanocrystalline strip 6 were replaced with a second modified nanocrystalline strip 4.
Comparative Example 6
[0091] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 2, except that a second modified nanocrystalline strip 4 was replaced with a first modified nanocrystalline strip 3 and a third modified nanocrystalline strip 5 was replaced with a fourth modified nanocrystalline strip 6.
Comparative Example 7
[0092] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 2, except that a first modified nanocrystalline strip 3 was replaced with a second modified nanocrystalline strip 4 and a third modified nanocrystalline strip 5 was replaced with a fourth modified nanocrystalline strip 6.
Comparative Example 8
[0093] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 2, except that a first modified nanocrystalline strip 3 and a second modified nanocrystalline strip 4 were replaced with a third modified nanocrystalline strip 5 and a third modified nanocrystalline strip 5 and a fourth modified nanocrystalline strip 6 were replaced with a second modified nanocrystalline strip 4.
Comparative Example 9
[0094] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 2, except that a fourth modified nanocrystalline strip 6 was replaced with a third modified nanocrystalline strip 5.
Comparative Example 10
[0095] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 2, except that a third modified nanocrystalline strip 5 was replaced with a fourth modified nanocrystalline strip 6.
[0096] A charging efficiency test was performed using a P9221-EVK wireless charging system receiver apparatus manufactured by IDT, and power of the test system was 15 W, which met the Qi standard. During the test, the release film was removed, and the nanocrystalline composite-structure magnetic sheet was fixed on a back side of a coil to test electrical energy transmission efficiency. The results are shown in the table below.
TABLE-US-00004 Electrical Energy Transmission Efficiency (%) Example 2 87.3 Comparative Example 5 84.6 Comparative Example 6 85.7 Comparative Example 7 85.5 Comparative Example 8 84.7 Comparative Example 9 86.1 Comparative Example 10 85.9
[0097] As can be seen from the above table, the charging efficiency of Example 2 is higher than that of Comparative Examples 5-10, indicating that the composite-structure magnetic sheet having gradient magnetic permeability provided in the present application is the best in magnetic shielding and magnetic conducting effectiveness and optimal in structure.
EXAMPLE 3
[0098] This example provides a nanocrystalline composite-structure magnetic sheet as shown in
[0099] A double-sided tape 2 of the first modified nanocrystalline strip 3 is connected to the release film 1. A double-sided tape 2 between two adjacent modified nanocrystalline strips is connected to the nanocrystalline strips. The double-sided tape 2 has a thickness of 5 μm, and each modified nanocrystalline strip has a thickness of 20 μm.
[0100] The first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are each independently the modified nanocrystalline strip prepared through the following preparation method. The preparation method includes the steps described below. [0101] (1) Roller-pressing treatment was performed on a nanocrystalline strip (Fe.sub.73.5Si.sub.13.5B.sub.9Nb.sub.3Cu, where the subscript value was a percentage of each element to a total mass of the nanocrystalline strip) with the double-sided tape 2 adhered to one side to obtain a micro-crushed nanocrystalline strip, where the roller-pressing treatment had a pressure of 65 kg, and the roller-pressing was performed for five times. [0102] (2) Acid corroding surface treatment was performed on the micro-crushed nanocrystalline strip obtained in step (1): a hydrochloric acid solution having a mass fraction of 1 wt % was coated on the surface of the micro-crushed nanocrystalline strip for surface acid treatment for 5 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0103] (3) Alkali washing surface treatment was performed on the nanocrystalline strip after the acid corroding surface treatment in step (2): a sodium hydroxide solution having a mass fraction of 1.5 wt % was coated on the surface of the nanocrystalline strip after the acid corroding surface treatment for surface alkali treatment for 9 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0104] (4) Three times of water washing, three times of absolute ethanol washing and drying were performed in sequence on the nanocrystalline strip obtained through the alkali washing surface treatment in step (3). [0105] (5) Micro-oxidation treatment was performed on the dried nanocrystalline strip in step (4) in an oxygen atmosphere having an oxygen concentration of 90 vol % for 28 min at 80° C. to obtain the modified nanocrystalline strip.
[0106] Real parts μ′ of magnetic permeability and imaginary parts μ″ of magnetic permeability of the first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are shown in the table below.
TABLE-US-00005 Real Part μ′ of Magnetic Imaginary Part μ″ of Permeability Magnetic Permeability First modified 436.6 27.9 nanocrystalline strip Second modified 711.1 52.7 nanocrystalline strip Third modified 1366.4 85.9 nanocrystalline strip Fourth modified 8856.2 158.4 nanocrystalline strip
Comparative Example 11
[0107] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 3, except that step (2), step (3), step (4) and step (5) were not performed when a first modified nanocrystalline strip 3 was prepared.
Comparative Example 12
[0108] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 3, except that a hydrochloric acid solution used in step (2) had a mass fraction of 0.45 wt % when a first modified nanocrystalline strip 3 was prepared.
Comparative Example 13
[0109] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 3, except that a hydrochloric acid solution used in step (2) had a mass fraction of 1.4 wt % when a first modified nanocrystalline strip 3 was prepared.
Comparative Example 14
[0110] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 3, except that surface acid treatment in step (2) was performed for 2.5 min when a first modified nanocrystalline strip 3 was prepared.
Comparative Example 15
[0111] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 3, except that surface acid treatment in step (2) was performed for 10 min when a first modified nanocrystalline strip 3 was prepared.
[0112] Magnetic permeability of the first modified nanocrystalline strips 3 obtained in Example 3 and Comparative Examples 11-15 and electrical energy transmission efficiency of the nanocrystalline composite-structure magnetic sheets are shown in the table below.
TABLE-US-00006 Real Part μ′ of Imaginary Part μ″ of Electrical Energy Magnetic Magnetic Transmission Permeability Permeability Efficiency (%) Example 3 436.6 27.9 87.3 Comparative 466.2 61.2 84.6 Example 11 Comparative 448.1 43.2 85.7 Example 12 Comparative 411.1 29.6 85.5 Example 13 Comparative 453.5 47.7 84.7 Example 14 Comparative 408.8 30.5 86.1 Example 15
[0113] As can be seen from the above table, compared with the nanocrystalline strips 1 in Comparative Examples 11-15, the first modified nanocrystalline strip 3 in Example 3 has a relatively high real part of magnetic permeability, a relatively low imaginary part of magnetic permeability and higher electrical energy transmission efficiency. The results indicate that the method for preparing a nanocrystalline strip provided in the present application has a relatively good magnetic conducting and magnetic shielding function and a relatively low loss; and when the process parameters of the acid corroding surface treatment exceed a limited range, the nanocrystalline strip has a relatively poor magnetic shielding and magnetic conducting effectiveness, and the wireless charging system constituted by the nanocrystalline strip has relatively poor charging efficiency.
EXAMPLE 4
[0114] This example provides a nanocrystalline composite-structure magnetic sheet as shown in
[0115] A double-sided tape 2 of the first modified nanocrystalline strip 3 is connected to the release film 1. A double-sided tape 2 between two adjacent modified nanocrystalline strips is connected to the nanocrystalline strips. The double-sided tape 2 has a thickness of 5 μm, and each modified nanocrystalline strip has a thickness of 20 μm.
[0116] The first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are each independently the modified nanocrystalline strip prepared through the following preparation method. The preparation method includes the steps described below. [0117] (1) Roller-pressing treatment was performed on a nanocrystalline strip (Fe.sub.73.5Si.sub.13.5B.sub.9Nb.sub.3Cu, where the subscript value was a percentage of each element to a total mass of the nanocrystalline strip) with the double-sided tape 2 adhered to one side to obtain a micro-crushed nanocrystalline strip, where the roller-pressing treatment had a pressure of 62 kg, and the roller-pressing was performed for four times. [0118] (2) Acid corroding surface treatment was performed on the micro-crushed nanocrystalline strip obtained in step (1): a hydrochloric acid solution having a mass fraction of 0.9 wt % was coated on the surface of the micro-crushed nanocrystalline strip for surface acid treatment for 6 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0119] (3) Alkali washing surface treatment was performed on the nanocrystalline strip after the acid corroding surface treatment in step (2): a sodium hydroxide solution having a mass fraction of 1.2 wt % was coated on the surface of the nanocrystalline strip after the acid corroding surface treatment for surface alkali treatment for 6 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0120] (4) Three times of water washing, three times of absolute ethanol washing and drying were performed in sequence on the nanocrystalline strip obtained through the alkali washing surface treatment in step (3). [0121] (5) Micro-oxidation treatment was performed on the dried nanocrystalline strip in step (4) in an oxygen atmosphere having an oxygen concentration of 98 vol % for 18 min at 70° C. to obtain the modified nanocrystalline strip.
[0122] Real parts μ′ of magnetic permeability and imaginary parts μ″ of magnetic permeability of the first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are shown in the table below.
TABLE-US-00007 Real Part μ′ of Magnetic Imaginary Part μ″ of Permeability Magnetic Permeability First modified 475.9 36.6 nanocrystalline strip Second modified 666.8 47.2 nanocrystalline strip Third modified 1178.9 81.2 nanocrystalline strip Fourth modified 9987.1 168.8 nanocrystalline strip
Comparative Example 16
[0123] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 4, except that alkali washing surface treatment in step (3) was not performed when a second modified nanocrystalline strip 4 was prepared.
Comparative Example 17
[0124] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 4, except that a sodium hydroxide solution used in step (3) had a mass fraction of 0.4 wt % when a second modified nanocrystalline strip 4 was prepared.
Comparative Example 18
[0125] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 4, except that a sodium hydroxide solution used in step (3) had a mass fraction of 2.5 wt % when a second modified nanocrystalline strip 4 was prepared.
Comparative Example 19
[0126] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 4, except that surface alkali treatment in step (3) was performed for 4.5 min when a second modified nanocrystalline strip 4 was prepared.
Comparative Example 20
[0127] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 4, except that surface alkali treatment in step (3) was performed for 12 min when a second modified nanocrystalline strip 4 was prepared.
[0128] Magnetic permeability of the second modified nanocrystalline strips 4 obtained in Example 4 and Comparative Examples 16-20 and electrical energy transmission efficiency of the nanocrystalline composite-structure magnetic sheets are shown in the table below.
TABLE-US-00008 Real Part μ′ of Imaginary Part μ″ of Electrical Energy Magnetic Magnetic Transmission Permeability Permeability Efficiency (%) Example 4 666.8 47.2 87.2 Comparative 612.4 45.3 85.9 Example 16 Comparative 631.1 46.4 86.1 Example 17 Comparative 642.1 47.1 86.3 Example 18 Comparative 644.6 48.6 86.1 Example 19 Comparative 662.7 48.2 87.1 Example 20
[0129] As can be seen from the above table, compared with the nanocrystalline strips 2 in Comparative Examples 16-19, the second modified nanocrystalline strip 4 in Example 4 has a relatively high real part of magnetic permeability, a relatively low imaginary part of magnetic permeability and higher electrical energy transmission efficiency. The magnetic performance and the electrical energy transmission efficiency of the second modified nanocrystalline strip 4 in Comparative Example 20 are substantially equivalent to those in Example 4, indicating that the overlong alkali washing time brings no performance improvement but cost waste. Therefore, the method for preparing a nanocrystalline strip provided in the present application has a relatively good magnetic conducting and magnetic shielding function and a relatively low loss, and when the alkali washing process is not adopted or the process parameters of the alkali washing exceed a limited range, the nanocrystalline strip has a relatively poor magnetic shielding and magnetic conducting effectiveness, and the wireless charging system constituted by the nanocrystalline strip has relatively poor charging efficiency.
EXAMPLE 5
[0130] This example provides a nanocrystalline composite-structure magnetic sheet as shown in
[0131] A double-sided tape 2 of the first modified nanocrystalline strip 3 is connected to the release film 1. A double-sided tape 2 between two adjacent modified nanocrystalline strips is connected to the nanocrystalline strips. The double-sided tape 2 has a thickness of 5 μm, and each modified nanocrystalline strip has a thickness of 20 μm.
[0132] The first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are each independently the modified nanocrystalline strip prepared through the following preparation method. The preparation method includes the steps described below. [0133] (1) Roller-pressing treatment was performed on a nanocrystalline strip (Fe.sub.73.5Si.sub.13.5B.sub.9Nb.sub.3Cu, where the subscript value was a percentage of each element to a total mass of the nanocrystalline strip) with the double-sided tape 2 adhered to one side to obtain a micro-crushed nanocrystalline strip, where the roller-pressing treatment had a pressure of 60 kg, and the roller-pressing was performed for five times. [0134] (2) Acid corroding surface treatment was performed on the micro-crushed nanocrystalline strip obtained in step (1): a hydrochloric acid solution having a mass fraction of 0.5 wt % was coated on the surface of the micro-crushed nanocrystalline strip for surface acid treatment for 8 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0135] (3) Alkali washing surface treatment was performed on the nanocrystalline strip after the acid corroding surface treatment in step (2): a sodium hydroxide solution having a mass fraction of 2 wt % was coated on the surface of the nanocrystalline strip after the acid corroding surface treatment for surface alkali treatment for 5 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0136] (4) Three times of water washing, three times of absolute ethanol washing and drying were performed in sequence on the nanocrystalline strip obtained through the alkali washing surface treatment in step (3). [0137] (5) Micro-oxidation treatment was performed on the dried nanocrystalline strip in step (4) in an oxygen atmosphere having an oxygen concentration of 90 vol % for 15 min at 85° C. to obtain the modified nanocrystalline strip.
[0138] Real parts μ′ of magnetic permeability and imaginary parts μ″ of magnetic permeability of the first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are shown in the table below.
TABLE-US-00009 Real Part μ′ of Magnetic Imaginary Part μ″ of Permeability Magnetic Permeability First modified 426.5 31.4 nanocrystalline strip Second modified 704.9 51.5 nanocrystalline strip Third modified 1299.3 84.6 nanocrystalline strip Fourth modified 8566.7 163.2 nanocrystalline strip
Comparative Example 21
[0139] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 5, except that alcohol washing in step (4) was not performed when a third modified nanocrystalline strip 5 was prepared.
[0140] Magnetic permeability of the third modified nanocrystalline strips 5 obtained in Example 5 and Comparative Example 21 and electrical energy transmission efficiency of the nanocrystalline composite-structure magnetic sheets are shown in the table below.
TABLE-US-00010 Real Part μ′ of Imaginary Part μ″ of Electrical Energy Magnetic Magnetic Transmission Permeability Permeability Efficiency (%) Example 5 1299.3 84.6 86.9 Comparative 1234.5 91.3 85.1 Example 21
[0141] As can be seen from the above table, compared with the third modified nanocrystalline strip 5 in
[0142] Comparative Example 21, the third modified nanocrystalline strip 5 in Example 5 has a relatively high real part of magnetic permeability, a relatively low imaginary part of magnetic permeability and higher electrical energy transmission efficiency. The results indicate that the alcohol washing is crucial in the preparation process of a nanocrystalline strip.
EXAMPLE 6
[0143] This example provides a nanocrystalline composite-structure magnetic sheet as shown in
[0144] A double-sided tape 2 of the first modified nanocrystalline strip 3 is connected to the release film 1. A double-sided tape 2 between two adjacent modified nanocrystalline strips is connected to the nanocrystalline strips. The double-sided tape 2 has a thickness of 5 μm, and each modified nanocrystalline strip has a thickness of 20 μm.
[0145] The first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are each independently the modified nanocrystalline strip prepared through the following preparation method. The preparation method includes the steps described below. [0146] (1) Roller-pressing treatment was performed on a nanocrystalline strip (Fe.sub.73.5Si.sub.13.5B.sub.9Nb.sub.3Cu, where the subscript value was a percentage of each element to a total mass of the nanocrystalline strip) with the double-sided tape 2 adhered to one side to obtain a micro-crushed nanocrystalline strip, where the roller-pressing treatment had a pressure of 70 kg, and the roller-pressing was performed for one time. [0147] (2) Acid corroding surface treatment was performed on the micro-crushed nanocrystalline strip obtained in step (1): a hydrochloric acid solution having a mass fraction of 1.2 wt % was coated on the surface of the micro-crushed nanocrystalline strip for surface acid treatment for 3 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0148] (3) Alkali washing surface treatment was performed on the nanocrystalline strip after the acid corroding surface treatment in step (2): a sodium hydroxide solution having a mass fraction of 0.5 wt % was coated on the surface of the nanocrystalline strip after the acid corroding surface treatment for surface alkali treatment for 10 min, and after the treatment was completed, the nanocrystalline strip was washed with deionized water. [0149] (4) Three times of water washing, three times of absolute ethanol washing and drying were performed in sequence on the nanocrystalline strip obtained through the alkali washing surface treatment in step (3). [0150] (5) Micro-oxidation treatment was performed on the dried nanocrystalline strip in step (4) in an oxygen atmosphere having an oxygen concentration of 85 vol % for 30 min at 60° C. to obtain the modified nanocrystalline strip.
[0151] Real parts μ′ of magnetic permeability and imaginary parts μ″ of magnetic permeability of the first modified nanocrystalline strip 3, the second modified nanocrystalline strip 4, the third modified nanocrystalline strip 5 and the fourth modified nanocrystalline strip 6 are shown in the table below.
TABLE-US-00011 Real Part μ′ of Magnetic Imaginary Part μ″ of Permeability Magnetic Permeability First modified 431.2 32.5 nanocrystalline strip Second modified 759.2 57.6 nanocrystalline strip Third modified 1365.9 88.6 nanocrystalline strip Fourth modified 9328.1 168.4 nanocrystalline strip
Comparative Example 22
[0152] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 6, except that micro-oxidation treatment in step (5) was not performed when a fourth modified nanocrystalline strip 6 was prepared.
Comparative Example 23
[0153] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 6, except that oxygen used in step (5) had a concentration of 83 vol % when a fourth modified nanocrystalline strip 6 was prepared.
Comparative Example 24
[0154] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 6, except that micro-oxidation treatment in step (5) was performed at 55° C. when a fourth modified nanocrystalline strip 6 was prepared.
Comparative Example 25
[0155] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 6, except that micro-oxidation treatment in step (5) was performed at 90° C. when a fourth modified nanocrystalline strip 6 was prepared.
Comparative Example 26
[0156] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 6, except that micro-oxidation treatment in step (5) was performed for 12 min when a fourth modified nanocrystalline strip 6 was prepared.
Comparative Example 27
[0157] A nanocrystalline composite-structure magnetic sheet provided in this comparative example was the same as that in Example 6, except that micro-oxidation treatment in step (5) was performed for 35 min when a fourth modified nanocrystalline strip 6 was prepared.
[0158] Magnetic permeability of the fourth modified nanocrystalline strips 6 obtained in Example 6 and Comparative Examples 22-27 and electrical energy transmission efficiency of the nanocrystalline composite-structure magnetic sheets are shown in the table below.
TABLE-US-00012 Real Part μ′ of Imaginary Part μ″ of Electrical Energy Magnetic Magnetic Transmission Permeability Permeability Efficiency (%) Example 6 9328.1 168.4 87.0 Comparative 9567.3 205.6 84.8 Example 22 Comparative 9512.6 197.3 85.2 Example 23 Comparative 9523.0 194.2 85.4 Example 24 Comparative 8977.6 178.6 84.2 Example 25 Comparative 9455.9 178.2 85.5 Example 26 Comparative 9035.4 181.2 84.5 Example 27
[0159] As can be seen from the above table, compared with the fourth modified nanocrystalline strips 6 in Comparative Examples 22-27, the fourth modified nanocrystalline strip 6 in Example 6 has a relatively high real part of magnetic permeability, a relatively low imaginary part of magnetic permeability and higher electrical energy transmission efficiency. The results indicate that whether the micro-oxidation and the limitation of the micro-oxidation process parameters are introduced seriously affects the magnetic performance and the electrical energy transmission efficiency of the nanocrystalline strip.
[0160] In conclusion, compared with the traditional preparation process of a nanocrystalline strip for wireless charging, the preparation method provided in the present application can give the modified nanocrystalline strip with a lower imaginary part of magnetic permeability and a lower loss which is more conducive to the wireless charging system obtaining high electrical energy transmission efficiency. In the present application, the acid corroding is performed on the micro-crushed nanocrystalline strip so that dilute hydrochloric acid enters into micro-cracks, and the bridges between micro-crushed units and sharp corners of the micro-crushed units are corroded, optimizing the microstructure of the strip and avoiding the magnetic field concentrating or unevenly distributing during the work. Subsequently, the acid, salt (sodium chloride generated by an acid-base reaction) and deionized water remaining on the surface of the nanocrystalline strip are removed through the alkali washing, the water washing and the alcohol washing, and finally, an extremely thin oxide film is formed on surfaces and edges of the micro-crushed units in the nanocrystalline strip through the micro-oxidation treatment, improving insulation of the nanocrystalline strip and further reducing eddy current loss of the nanocrystalline strip.
[0161] The magnetic performance of each nanocrystalline strip of the nanocrystalline composite-structure magnetic sheet in the present application is strictly limited to form the composite structure having a gradient magnetic conducting characteristic. The first modified nanocrystalline strip is closest to the wireless charging system, which has a characteristic of relatively low loss to guarantee the efficiency of the wireless charging system. The outermost fourth modified nanocrystalline strip has a high real part of magnetic permeability, and the magnetic shielding effectiveness is excellent, avoiding a magnetic field radiation of the wireless charging system. That is, the synergy among the first modified nanocrystalline strip, the second modified nanocrystalline strip, the third modified nanocrystalline strip and the fourth modified nanocrystalline strip allows the nanocrystalline composite-structure magnetic sheet to possess good electrical energy transmission efficiency.
[0162] The applicant states that the preceding are merely specific examples of the present application and are not to limit the protection scope of the present application.