TWI684747B - Method for measuring magnetic quantity of sintered NdFeB magnet products by using magnetic flux meter, balance and damagnetization coil - Google Patents

Abstract

The invention provides a magnetic measurement method for sintered NdFeB magnets, which can simplify the current measurement method, and is characterized in that the magnetic properties of the sintered NdFeB magnet products can be inspected according to the specifications by using a magnetic flux meter, a balance and a demagnetization coil. It can be applied to the final product of sintered NdFeB magnet with different shapes. The equipment for the measurement is cheap and the measured process is simple and fast.

Description

Method for measuring magnetic properties of sintered NdFeB magnet products using magnetic flux meter, balance and demagnetization coil

The invention relates to a magnetic detection method for sintered NdFeB magnet products; more specifically, it particularly refers to a magnetic measurement method for sintered NdFeB magnet products using a magnetic flux meter, a balance and a demagnetization coil.

Sintered NdFeB magnet has been widely used in many fields such as electronic information, automobile industry, medical equipment, energy transportation and so on. At the same time, as technology continues to progress and costs continue to decline, in many emerging fields, NdFeB permanent magnet materials have shown broad application prospects. Especially under the trend of low-carbon economy sweeping the world, all countries in the world are paying attention to environmental protection and low-carbon emissions as key scientific and technological fields. This has put forward new requirements for improving the energy structure, developing renewable energy, improving efficiency, saving energy and reducing emissions, and promoting low-carbon life. It also provides the development of low-carbon economic industries such as wind power generation, new energy vehicles, and energy-saving home appliances. Broad market space.

The magnetic measurement method of the conventional sintered NdFeB magnet is based on the standards of IEC 60404-5, JIS C2501 and GBT 3217-2013. Standard magnetic measurement equipment is required for measurement, and the measurement samples are standardized, such as: (1 ) The shape must be a cylinder with a circular or rectangular cross-section. (2) The thickness of the test piece shall not be less than 5 mm. (3) The size of the test piece shall not be greater than the diameter of the uniform magnetic field of the pole of the electromagnet used in the standard magnetic measurement equipment. (4) There are strict requirements on the tolerance of the parallelism and verticality of the test piece, and the roughness of the surface of the test piece.

The standard magnetic measurement equipment used in the conventional measurement method is expensive and the measurement sample The products are measured by processing semi-finished square blanks of sintered NdFeB magnets. It is impossible to detect common final products of sintered NdFeB magnets, such as tile magnets and thin magnets (thickness less than 5mm).

In view of this, the present invention provides a magnetic measurement method for sintered NdFeB magnet products, which is characterized by using a magnetic flux meter, a balance and a demagnetizing coil to check whether the magnetic properties of the sintered NdFeB magnet products meet the specifications. It can be applied to sintered NdFeB magnets with different shapes. The equipment is cheap and the measurement method is simple and fast.

The main purpose of the present invention is to use the magnetic fluxmeter, balance and demagnetization coil to check whether the magnetic properties of the sintered NdFeB magnet products meet the specifications. This method can be applied to sintered NdFeB magnet products of different shapes. The equipment is cheap and The measurement method is simple and fast.

According to the above purpose, the magnetic measurement method of the sintered NdFeB magnet product of the present invention is as follows: (a) A sintered NdFeB magnet known to meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications Use a balance to measure the weight W; (b) Then the magnet measures the magnetic flux value M with a magnetic flux meter, and divides the magnetic flux value M by the weight W of the magnet measured in step a to obtain the magnetic Br and magnetic energy product (BH) ) The magnetic value of max sintered NdFeB magnet M/W; (c) The same brand but unknown whether it meets the magnetic Br and magnetic energy product (BH) max sintered NdFeB magnet to measure the above steps a and b Measure the weight W1 and the magnetic flux value M1 respectively. If the measured magnetic value M1/W1 is greater than or equal to the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet complies with the brand of magnetic Br and magnetic energy product (BH ) max specification, conversely, if the measured magnetic value M1/W1 is less than the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet does not meet the specifications of the magnetic Br and magnetic energy product (BH) max specifications of the brand; (d) The sintered NdFeB magnet known to meet the magnetic coercive force (iHc) specifications of the brand is measured with a magnetic flux meter to obtain a magnetic flux value M2; (e) The magnet is then demagnetized by a demagnetizing coil to generate a reverse magnetic field to demagnetize the sintered NdFeB magnet one by one; (f) After each demagnetization, use the magnetic flux measurement to measure the magnetic flux value of the magnet and record the demagnetization The demagnetization magnetic field H required for the magnetic flux value of the magnet to decline by 10%; (g) A sintered neodymium iron boron magnet of the same shape and the same brand but unknown whether it meets the magnetic coercive force (iHc) specification is measured with a magnetic flux meter, and then the magnetic flux value M3, then After demagnetizing the magnet with the demagnetization field H obtained in step f, the magnetic flux value M4 is measured with a magnetic flux meter. The measured M4 is compared with M3. If the magnetic flux decline is less than or equal to 10%, the sintered NdFeB magnet is judged Conforms to the grade of magnetic coercive force (iHc) specifications, otherwise, if the flux decline is greater than 10%, it is determined that the sintered NdFeB magnet does not meet the grade of magnetic coercive force (iHc) specifications; and (h) different shapes are the same If it is determined whether the grade of sintered NdFeB magnet meets the specification of the magnetic coercive force (iHc) of the grade, the aforementioned steps d to f are required.

The magnetic energy product (BH)max of the sintered NdFeB magnet may be 30-55 (MGOe), and the coercive force iHc may be 10-40 (kOe).

The magnetic flux value M of the sintered neodymium iron boron measured using a magnetic flux meter may be a moment, flux, or intergrator.

The magnetic field generated by the demagnetization coil is 0.1~4(T).

The shape of the sintered NdFeB magnet may be cylindrical, pie-shaped or tile-shaped.

When the shape of the sintered NdFeB magnet is a cylinder, the diameter is 15-20 mm, and the thickness is 8-10 mm.

When the shape of the sintered NdFeB magnet is pie-shaped, the diameter is 15-20 mm, and the thickness is 4-5 mm.

When the shape of the sintered NdFeB magnet is a tile, the outer diameter is 24 to 25 mm, the inner diameter is 22 to 23 mm, the length is 23 to 25 mm, the width is 10 to 11 mm, and the thickness is 1 to 2 mm.

The thickness of the sintered NdFeB magnet is 10 mm or less.

According to another magnetic measurement method of the sintered NdFeB magnet product of the present invention, the measurement method is as follows: (a) A sintered NdFeB magnet known to meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications is used for the balance Measure the weight W; (b) Then the magnet measures the magnetic flux value M with a magnetic flux meter, and divides the magnetic flux value M by the magnet weight W measured in step a to obtain the specifications of the magnetic Br and magnetic energy product (BH)max The magnetic value of sintered NdFeB magnet is M/W; (c) The sintered NdFeB magnet of the same brand but unknown whether it meets the specifications of magnetic Br and magnetic energy product (BH) max is measured in steps a and b above, and measured separately Obtain the weight W1 and the magnetic flux value M1. If the measured magnetic value M1/W1 is greater than or equal to the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet meets the specifications of the magnetic Br and magnetic energy product (BH)max specifications Conversely, if the measured magnetic value M1/W1 is less than the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet does not meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications of the grade; (d) will be known The sintered NdFeB magnet that meets the specifications of the magnetic coercive force (iHc) specification is measured with a magnetic flux meter M2; (e) The magnet is then demagnetized coil to generate a reverse magnetic field from small to large one by one to produce a sintered NdFeB magnet Perform demagnetization; (f) After each demagnetization, use the magnetic flux measurement to measure the magnetic flux value of the magnet, and record the demagnetization magnetic field H required for the magnetic flux value to decline by 10% after demagnetization; (g) The same shape and the same brand but unknown Whether the sintered NdFeB magnet that meets the magnetic coercive force (iHc) specification is measured with a magnetic flux meter M3, then demagnetized with the demagnetizing field H obtained in step f, and then measured with a magnetic flux meter M4, Compared with the measured M4 and M3, if the magnetic flux decline is less than or equal to 10%, it is judged that the sintered NdFeB magnet meets the grade of magnetic coercive force (iHc) specifications. On the contrary, if the magnetic flux decline is greater than 10%, it is judged The sintered NdFeB magnet The stone does not meet the specifications for the magnetic coercive force (iHc) of the grade; and (h) Sintered NdFeB magnets with the same shape and different shapes are judged to meet the specifications for the magnetic coercive force (iHc) of the grade. ; Wherein the shape of the sintered NdFeB magnet can be cylindrical, pie-shaped or tile-shaped; the thickness of the sintered NdFeB magnet is less than 5mm.

In order to have a more detailed understanding of the purpose, efficacy, features, and structure of the present invention, the preferred embodiments are described below with reference to the drawings.

A‧‧‧Cylinder

B‧‧‧Pie shape

C‧‧‧Tile

Step a~h‧‧‧Sintered NdFeB magnet magnetic measurement method steps

Figure 1: Flow chart of the magnetic measurement method of the sintered NdFeB magnet of the present invention; Figure 2: Schematic diagram of the sintered NdFeB magnet of the present invention.

FIG. 1 is a flowchart of the magnetic measurement method of the sintered NdFeB magnet of the present invention. Please refer to FIG. 1; from FIG. 1, it can be seen that the magnetic measurement method of the sintered NdFeB magnet of the present invention is as follows: (a) It will be known to meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications of the brand The sintered NdFeB magnet uses a balance to measure the weight W; (b) Then the magnet measures the magnetic flux value M with a magnetic flux meter, and divides the magnetic flux value M by the weight W of the magnet measured in step a to obtain the magnetic Br and magnetic energy product (BH) max sintered NdFeB magnets with magnetic value M/W; (c) Sintered NdFeB magnets of the same brand but unknown whether they meet the magnetic Br and magnetic energy product (BH) max specifications In the measurement of a and b, the weight W1 and the magnetic flux value M1 are respectively measured. If the measured magnetic value M1/W1 is greater than or equal to the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet is in compliance with the magnetic brand Br and magnetic energy product (BH) max specifications, conversely, if the measured magnetic value M1/W1 is less than the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet does not meet the brand of magnetic Br and magnetic energy product (BH) max specification (d) The sintered NdFeB magnet known to meet the magnetic coercive force (iHc) specifications of the brand is measured with a magnetic flux meter for the magnetic flux value M2; (e) The magnet is then generated in a demagnetizing coil from small to large to generate a reverse magnetic field. Demagnetize the sintered NdFeB magnet; (f) After each demagnetization, use the magnetic flux measurement to measure the magnetic flux value of the magnet, and record the demagnetizing magnetic field H required for the magnetic flux value to decline by 10% after demagnetization; (g) A sintered NdFeB magnet of the same shape and the same brand but unknown whether it meets the magnetic coercive force (iHc) specification is measured with a magnetic flux meter, and then demagnetized by the demagnetizing field H obtained in step f, and then measured with a magnetic flux meter Obtain the magnetic flux value M4, and compare the measured M4 with M3. If the magnetic flux decline is less than or equal to 10%, it is determined that the sintered NdFeB magnet meets the grade of magnetic coercive force (iHc) specifications. On the contrary, the magnetic flux decline if If it is greater than 10%, it is determined that the sintered NdFeB magnet does not meet the specifications of the magnetic coercive force (iHc) of the grade; and (h) Sintered NdFeB magnets with the same shape and different shapes are judged whether they conform to the magnetic coercive force of the grade (iHc) ) Specifications, you need to go through the above steps d to f.

2 is a schematic diagram of the sintered NdFeB magnet of the present invention. Please refer to Figure 1 and Figure 2; the first embodiment of the present invention, (I) magnetic Br, (BH)max and iHc meet N50H specifications, (II) magnetic Br and (BH)max are higher than N50H specifications And iHc is lower than N50H specification, and (III) magnetic iHc is higher than N50H specification and Br and (BH)max are lower than N50H specification sintered NdFeB magnet blanks are processed into cylinder A, pie B and tile shape respectively C, as shown in Figure 2, the dimensions are cylinder A: diameter 20mm, thickness 9.1mm; pie shape B: diameter 20mm, thickness 4.3mm; tile shape C: outer R 25mm, inner R 23mm, length 25mm, The width is 11mm and the thickness is 2mm. The conventional magnetic measurement method and the magnetic measurement method of the sintered NdFeB magnet provided by the present invention are used to measure and test the magnetic properties of the products. The measured magnetic values are listed in Table 1.

From the comparison results in Table 1, it can be found that the conventional magnetic measurement method of sintered NdFeB magnet can only measure the standard shape cylinder A sample with a thickness greater than 5mm, and the thinner pie B sample and tile C sample It cannot be measured, and only a sintered NdFeB magnet magnetic measurement method provided by the present invention can be used for magnetic verification.

Using the conventional magnetic measurement method to measure the sample of cylinder A, it can be found that the magnetic Br, (BH)max and iHc of sample IA meet the N50H specification, and the magnetic Br and (BH)max of sample II-A are higher than the N50H specification and iHc Below the N50H specification, and the magnetic iHc of sample III-A is higher than the N50H specification and Br and (BH)max are lower than the N50H specification, using the measurement method provided by the present invention, in terms of magnetic Br and (BH)max specification inspection , The magnetic M/W of sample IA that meets N50H specifications is 116 * 10 ^-5 (Vs/g), and the magnetic property of sample II-A is measured to be 116.39* 10 ^-5 (Vs/g) greater than 116* 10 ^-of sample IA ⁵ (Vs/g), it can be judged that the magnetic Br and (BH)max meet the N50H specification, and the magnetic M/W of sample III-A is measured to be 115.12* 10 ^-5 (Vs/g) is less than 116* 10 ^-of sample IA ⁵ (Vs/g), it can be judged that the magnetic Br and (BH)max do not meet the N50H specification, the result is the same as the conventional measurement method; in terms of the magnetic iHc specification inspection, the IA flux decline of the sample that meets the N50H specification is measured The demagnetizing field required for 10% is 8.88 (kG). After demagnetizing the sample II-A with this demagnetizing field, the magnetic flux decay is greater than 10%. It can be determined that the magnetic iHc does not meet the N50H specification, and the sample III-A is demagnetized by this demagnetizing field. After demagnetization, the flux decline is less than 10%, and it can be judged that the magnetic iHc meets the N50H specification, and the result is the same as the conventional measurement method.

Because the thickness of the pie-shaped sample B is less than 5 mm, the conventional measurement method cannot be measured. With the measurement method provided by the present invention, the magnetic properties of II-B can be found in the specification inspection of magnetic Br and (BH)max M/W is greater than IB, it can be judged that the magnetic Br and (BH)max magnetism meets the N50H specification, and the magnetic M/W of sample III-B is less than IB, so it can be judged that the magnetic Br and (BH)max magnetism does not meet the N50H specification. The measurement results of sample A are the same; in the aspect of iHc specification inspection, the demagnetization field required to measure the 10% magnetic flux decline of N50H specification sample II-B is 7.05 (kG). After demagnetization, the magnetic flux decline is greater than 10%, so it can be determined that the magnetic iHc magnetism does not meet the N50H specification. After demagnetizing the sample III-B, the magnetic flux decline is less than 10%, and the magnetic iHc magnetism can be determined to meet the N50H specification. The measurement results of the cylinder A sample are the same.

Because the tile-shaped C sample is not a standard rectangle or circle required by the conventional measurement method, it cannot be measured. With the measurement method provided by the present invention, in terms of the specification inspection of magnetic Br and (BH)max, It can be found that the magnetic M/W of II-C is greater than IC, it can be judged that the magnetic Br and (BH)max magnetic meet the N50H specification, and the magnetic M/W of sample III-C is smaller than IC, it can be judged that the magnetic Br and (BH)max are not magnetic Meet the N50H specification, the results are the same as the measurement results of sample A and sample B; in terms of magnetic iHc specification inspection, the demagnetization field required to measure the magnetic flux decline of 10% for sample II-C conforming to N50H specification is 6.02 (kG) After the demagnetization demagnetizes the sample II-C, the magnetic flux declines by more than 10%. It can be judged that the magnetic iHc magnetism does not meet the N50H specifications. After demagnetizing the sample III-C, the magnetic flux decline by less than 10% can be judged. The magnetic iHc magnetic meets the N50H specification, and the results are the same as the measurement results of the cylinder A sample and the pie B sample.

According to the results in Table 1, it is found that in the measurement method provided by the present invention, the magnetic value M/W will not change with the shape of the test piece, and the demagnetizing field H will vary with the shape of the test piece It is different.

Please refer to Figure 1 and Figure 2; the second embodiment of the present invention, (IV) magnetic Br, (BH)max and iHc meet N42SH specifications, (V) magnetic Br and (BH)max are higher than N42SH specifications And iHc is lower than N42SH specification, and (VI) magnetic iHc is higher than N42SH specification and Br and (BH)max are lower than N42SH specification sintered NdFeB magnet blanks are processed into cylinder A, pie B and tile shape respectively C, the size and shape are the same as [Example 1]. As shown in FIG. 2, the magnetic measurement method of the product is measured and tested using the conventional measurement method and a magnetic measurement method of sintered NdFeB magnet provided by the present invention. The magnetic value is listed in Table 2.

From the comparison results in Table 2, it can be found that the conventional magnetic measurement method of sintered NdFeB magnet can only measure the standard shape cylinder A sample with a thickness greater than 5mm, and the thinner pie B sample and tile C sample It cannot be measured, and only a sintered NdFeB magnet magnetic measurement method provided by the present invention can be used for magnetic verification.

Using the conventional magnetic measurement method to measure the sample of cylinder A, it can be found that the magnetic Br, (BH)max and iHc of sample IV-A meet the N42SH specification, and the magnetic Br and (BH)max of sample VA are higher than the N42SH specification and iHc is lower than the N42SH specification, and the magnetic iHc of sample VI-A is higher than the N42SH specification and Br and (BH)max are lower than the N42SH specification, using the measurement method provided by the present invention, in terms of Br and (BH)max specification inspection , The magnetic M/W of sample IV-A that meets N42SH specifications is 107.1*10 ^-5 (Vs/g), and the magnetic M/W of sample VA is measured to be 109.3*10 ^-5 (Vs/g) greater than that of IV-A 107.1*10 ^-5 (Vs/g), it can be judged that the magnetic Br and (BH)max magnetic meet the N42SH specification, and the magnetic M/W of sample VI-A is measured to be 105.84*10 ^-5 (Vs/g) less than IV- A's 107.1*10 ^-5 (Vs/g), it can be judged that the magnetic Br and (BH)max magnetic does not meet the N42SH specification, the result is the same as the conventional measurement method; in terms of iHc specification inspection, the measurement meets N42SH The demagnetization field required for the sample IV-A magnetic flux decline of 10% is 13.78 (kG). This demagnetization field demagnetizes the sample VA, and the magnetic flux decline is greater than 10%. It can be determined that the magnetic iHc magnet does not meet the N42SH specification. After demagnetizing sample VI-A, the magnetic flux decline is less than 10%, so it can be judged that the magnetic iHc magnet meets the N42SH specification, and the result is the same as the conventional measurement method.

Because the thickness of the pie-shaped sample B is less than 5 mm, the conventional measurement method cannot be measured. With the measurement method provided by the present invention, the magnetic M/V of VB can be found in the specification inspection of magnetic Br and (BH)max W is greater than IV-B, it can be judged that the magnetic Br and (BH)max magnetism meets the N42SH specification, and the M/W of the sample VI-B is less than IV-B, it can be judged that the magnetic Br and (BH)max magnetism does not meet the N42SH specification, the result The measurement result is the same as the cylinder A sample; in the iHc specification test, the demagnetization field required to measure the IV-B magnetic flux decline of 10% of the N42SH specification sample is 11.25 (kG). After VB demagnetization, the magnetic flux decline is greater than 10%, it can be determined that the magnetic iHc magnetism does not meet the N42SH specification. After demagnetizing the sample VI-B with this demagnetization, the magnetic flux decline is less than 10%, so it can be determined that the magnetic iHc magnetism meets the N42SH specification. The result is the same as the measurement result of the cylinder A sample.

Because the tile-shaped C sample is not a standard rectangle or circle required by the conventional measurement method, it cannot be measured. With the measurement method provided by the present invention, in terms of Br and (BH)max specification inspection, It is found that the magnetic M/W of VC is greater than IV-C, and the magnetic Br and (BH)max magnetic meets N42SH specification, sample VI-C has magnetic M/W less than IV-C, it can be judged that magnetic Br and (BH)max magnetic does not meet N42SH specification, the result is similar to cylinder A sample and pie B sample The measurement results are the same; in the iHc specification inspection, the demagnetization field required to measure the 10% of the IV-C flux decline of the N42SH specification sample is 9.70 (kG). After demagnetization, the sample VC is demagnetized. If the flux decay is greater than 10%, it can be determined that the magnetic iHc magnet does not meet the N42SH specification. After demagnetizing the sample VI-C with a demagnetizing field, the magnetic flux decay is less than 10%. It can be determined that the magnetic iHc magnetism meets the N42SH specification. The result is the same as the cylinder A sample The measurement result is the same as that of the pie B sample.

According to the results in Table 2, it is found that in the measurement method provided by the present invention, the magnetic value M/W will not change with the shape of the test piece, and the demagnetizing field will vary with the shape of the test piece. The result is the same as [Example 1].

Please refer to Figure 1 and Figure 2; the third embodiment of the present invention, (VII) magnetic Br, (BH)max and iHc meet N38UH specifications, (VIII) magnetic Br and (BH)max are higher than N38UH specifications And iHc is lower than N42SH specification, and (IX) magnetic iHc is higher than N38UH specification and Br and (BH)max are lower than N38UH specification sintered NdFeB magnet blanks are processed into cylinder A, pie B and tile shape respectively C, the size and shape are the same as [Example 1]. As shown in FIG. 2, the magnetic measurement method of the product is measured and tested using the conventional measurement method and a magnetic measurement method of sintered NdFeB magnet provided by the present invention. The magnetic value is listed in Table 3.

From the comparison results in Table 3, it can be found that the conventional magnetic measurement method of sintered NdFeB magnet can only measure the standard shape cylinder A sample with a thickness greater than 5mm, while the thinner pie B sample and tile C sample It cannot be measured, and only a sintered NdFeB magnet magnetic measurement method provided by the present invention can be used for magnetic verification.

Using the conventional magnetic measurement method to measure the sample of cylinder A, it can be found that the magnetic Br, (BH)max and iHc of sample VII-A meet the N38UH specification, and the magnetic Br and (BH)max of sample VIII-A are higher than N38UH Specifications and iHc is lower than N38UH specifications, and the magnetic iHc of sample IX-A is higher than N38UH specifications and Br and (BH)max are lower than N38UH specifications, using the measurement method provided by the present invention, the magnetic Br and (BH)max In terms of specification inspection, the magnetic M/W of sample VII-A that meets N38UH specifications is 101.4*10 ^-5 (Vs/g), and the magnetic M/W of sample VIII-A is measured as 102.92* 10 ^-5 (Vs/g )101.4*10 ^-5 (Vs/g) greater than VII-A, it can be judged that the magnetic Br and (BH)max meet the N38UH specification, and the magnetic M/W of sample IX-A is measured to be 100.12* 10 ^-5 (Vs/ g) Less than 101.4*10 ^-5 (Vs/g) of VII-A, it can be judged that the magnetic Br and (BH)max do not meet the N38UH specification, the result is the same as the conventional measurement method; in terms of iHc specification inspection, the amount The demagnetization field required to measure 10% of the magnetic flux decay of sample VII-A that meets N38UH specifications is 18.05 (kG). After demagnetizing the sample VIII-A with this demagnetization, the magnetic flux decay is greater than 10%. It can be judged that the magnetic iHc is not magnetic It meets the N38UH specification. After demagnetizing the sample XI-A with this demagnetizing field, the magnetic flux decline is less than 10%. It can be judged that the magnetic iHc magnetism meets the N38UH specification. The result is the same as the conventional measurement method.

Because the thickness of the pie-shaped sample B is less than 5 mm, the conventional measurement method cannot be measured. With the measurement method provided by the present invention, the sample VIII-B can be found in the specification inspection of magnetic Br and (BH)max The magnetic M/W is greater than VII-B, it can be judged that the magnetic Br and (BH)max meet the N38UH specification, and the magnetic M/W of the sample IX-B is less than VII-B, which can be judged that the magnetic Br and (BH)max do not meet the N38UH specification , The result is the same as the measurement result of the cylinder A sample; in terms of magnetic iHc specification inspection, the demagnetization field required to measure the 10% magnetic flux decline of the sample VII-B that meets the N38UH specification is 15.43 (kG) After the magnetic field demagnetizes sample VIII-B, the magnetic flux declines greatly At 10%, it can be determined that the magnetic iHc does not meet the N38UH specification. After demagnetizing the sample IX-B by demagnetization, the magnetic flux decline is less than 10%, so it can be determined that the magnetic iHc meets the N38UH specification. The result is measured with the cylinder A sample The result is the same.

Because the tile-shaped C sample is not a standard rectangle or circle required by the conventional measurement method, it cannot be measured. With the measurement method provided by the present invention, in terms of the specification inspection of magnetic Br and (BH)max, It can be found that the magnetic M/W of sample VIII-C is greater than VII-C, it can be judged that the magnetic Br and (BH)max meet the N38UH specification, and the magnetic property of sample IX-C is less than VII-C, it can be judged that the magnetic Br and (BH)max are not Meet the N38UH specification, the result is the same as the measurement result of the cylindrical A sample and the pie B sample; in terms of the magnetic iHc specification test, the demagnetization field required for the VII-C magnetic flux decline of 10% of the N38UH specification sample is measured It is 13.84 (kG). After demagnetizing the sample VIII-C with this demagnetizing field, the magnetic flux decline is greater than 10%. It can be judged that the magnetic iHc does not meet the N38UH specification. After demagnetizing the sample IX-C with this demagnetizing field, the magnetic flux decline is less than 10%, it can be judged that the magnetic iHc meets the N38UH specification, and the results are the same as the measurement results of the cylindrical A sample and the pie-shaped B sample.

According to the results in Table 3, it is found that in the measurement method provided by the present invention, the magnetic value M/W will not change with the shape of the test piece, and the demagnetizing field will vary with the shape of the test piece. The results are similar to [Example 1] and [Example 2].

The magnetic measurement method of another sintered NdFeB magnet of the present invention is as follows: (a) A sintered NdFeB magnet known to meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications is used to measure the weight using a balance W; (b) Next, the magnetic flux is measured by the magnetic flux meter, and the magnetic flux value M is divided by the weight W of the magnet measured in step a to obtain sintered neodymium that meets the specifications of the brand of magnetic Br and magnetic energy product (BH)max The magnetic value of iron boron magnet M/W; (c) The sintered neodymium iron boron magnet of the same brand but unknown whether it meets the specifications of magnetic Br and magnetic energy product (BH) max is measured in steps a and b above, and the weight is measured respectively W1 and magnetic flux value M1, If the measured magnetic value M1/W1 is greater than or equal to the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet meets the specifications of the brand of magnetic Br and magnetic energy product (BH)max, otherwise, if the magnetic value M1 is measured /W1 is less than the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet does not meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications of the grade; (d) it will be known to conform to the magnetic coercive force of the grade (iHc ) The sintered NdFeB magnet of the specification is measured with a magnetic flux meter. The magnetic flux value M2; (e) The magnet is then demagnetized with a demagnetizing coil to generate a reverse magnetic field one by one to demagnetize the sintered NdFeB magnet; (f) each time After demagnetization, use the magnetic flux measurement to measure the magnetic flux value of the magnet, and record the demagnetization magnetic field H required for the magnetic flux value to decline by 10% after demagnetization; (g) The same shape and the same brand but unknown whether it is consistent with the magnetic coercivity (iHc) The sintered NdFeB magnet of the specification is measured with a magnetic flux meter for the magnetic flux value M3, and then demagnetized with the demagnetizing field H obtained in step f, and then measured with the magnetic flux meter for the magnetic flux value M4. The measured M4 is compared with M3. If the flux decline is less than or equal to 10%, it is determined that the sintered NdFeB magnet meets the grade of magnetic coercive force (iHc) specifications. On the contrary, if the flux decline is greater than 10%, it is determined that the sintered NdFeB magnet does not meet this Grades of magnetic coercive force (iHc) specifications; and (h) sintered NdFeB magnets of the same shape in different shapes. If it is determined whether they meet the grades of magnetic coercive force (iHc) specifications, the aforementioned steps d to f are required; wherein the sintering The shape of the NdFeB magnet can be cylindrical, pie-shaped or tile-shaped; the thickness of the sintered NdFeB magnet is 5 mm or less.

Therefore, the present invention has excellent progress and practicability among similar products. After searching domestic and foreign technical information documents, it has not been found that the same or similar structure or technology existed before the application in this case. This case should have met the patent requirements of "inventiveness", "compatibility with industry utilization", and "progressiveness", and the application should be filed according to law.

However, the above are only the preferred embodiments of the present invention, and any other equivalent structural changes that apply to the description of the present invention and the scope of patent application should be included in this Within the scope of patent applications for inventions.

Step a~h‧‧‧Sintered NdFeB magnet magnetic measurement method steps

Claims (10)

A magnetic measurement method for sintered NdFeB magnets. The measurement methods are as follows: (a) A sintered NdFeB magnet known to meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications is used to measure the weight W with a balance; b) Next, the magnet is measured with a magnetic flux meter, and the magnetic flux value M is divided by the weight W of the magnet measured in step a to obtain a sintered NdFeB magnet that meets the specifications of the brand of Magnetic Br and Magnetic Energy Product (BH)max The magnetic value of M/W; (c) The sintered neodymium iron boron magnets of the same grade but unknown whether they meet the specifications of magnetic Br and magnetic energy product (BH) max are measured in steps a and b above, and the weight W1 and magnetic are measured respectively General value M1, if the measured magnetic value M1/W1 is greater than or equal to the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet meets the specifications of the brand of magnetic Br and magnetic energy product (BH)max, otherwise, if the amount If the measured magnetic value M1/W1 is less than the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet does not meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications of the brand; (d) it is known to meet the magnetic correction of the brand The sintered NdFeB magnet of the coercive force (iHc) specification measures the magnetic flux value M2 with a magnetic flux meter; (e) The magnet is then demagnetized with a demagnetizing coil to generate a reverse magnetic field one by one to demagnetize the sintered NdFeB magnet; (f ) After each demagnetization, use the magnetic flux measurement to measure the magnetic flux value of the magnet, and record the demagnetization magnetic field H required for the magnetic flux value to decline by 10% after demagnetization; (g) The same shape and the same brand but unknown whether it is consistent with magnetic coercion The sintered NdFeB magnet with force (iHc) specification is measured with a magnetic flux meter for the magnetic flux value M3, and then demagnetized with the demagnetizing field H obtained in step f, and then measured with the magnetic flux meter for the magnetic flux value M4, the measured M4 and M3 In comparison, if the magnetic flux decline is less than or equal to 10%, the sintered NdFeB magnet is judged to meet the grade of magnetic coercive force (iHc) specifications. On the contrary, if the magnetic flux decline is greater than 10%, the sintered NdFeB magnet is judged Failure to comply with the magnetic coercive force (iHc) specifications of the grade; and (h) Sintered neodymium iron boron magnets with the same shape and different shapes. If it is determined whether the magnetic coercive force (iHc) specifications of the grade are met, the aforementioned steps d to f are required. The magnetic measurement method of sintered NdFeB magnet according to claim 1, wherein the magnetic energy product (BH)max of the sintered NdFeB magnet can be 30~55 (MGOe), and the coercive force iHc can be 10~40 (kOe). The magnetic measurement method of sintered NdFeB magnet according to claim 1, wherein the magnetic flux value M of the sintered NdFeB magnet measured by a magnetic flux meter may be a moment, flux or intergrator ). The magnetic measurement method of sintered NdFeB magnet as described in claim 1, wherein the demagnetization coil can generate a magnetic field of 0.1~4(T). The magnetic measurement method of sintered NdFeB magnet according to claim 1, wherein the shape of the sintered NdFeB magnet may be a cylinder, a pie shape or a tile shape. The magnetic measurement method for sintered NdFeB magnet according to claim 5, wherein when the shape of the sintered NdFeB magnet is a cylinder, the diameter is 15-20 mm, and the thickness is 8-10 mm. The magnetic measurement method of sintered NdFeB magnet according to claim 5, wherein when the shape of the sintered NdFeB magnet is pie-shaped, the diameter is 15-20 mm, and the thickness is 4-5 mm. The magnetic measurement method of sintered NdFeB magnet according to claim 5, wherein, when the shape of the sintered NdFeB magnet is tile-shaped, the outer diameter is 24~25mm, the inner diameter is 22~23mm, and the length is 23~ 25mm, width 10~11mm, thickness 1~2mm. The magnetic measurement method of sintered NdFeB magnet according to claim 1, wherein the sintered NdFeB magnet The thickness of the magnet is 10 mm or less. A magnetic measurement method for sintered NdFeB magnets. The measurement methods are as follows: (a) A sintered NdFeB magnet known to meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications is used to measure the weight W with a balance; b) Next, the magnet is measured with a magnetic flux meter, and the magnetic flux value M is divided by the weight W of the magnet measured in step a to obtain a sintered NdFeB magnet that meets the specifications of the brand of Magnetic Br and Magnetic Energy Product (BH)max The magnetic value of M/W; (c) The sintered neodymium iron boron magnets of the same grade but unknown whether they meet the specifications of magnetic Br and magnetic energy product (BH) max are measured in steps a and b above, and the weight W1 and magnetic are measured respectively General value M1, if the measured magnetic value M1/W1 is greater than or equal to the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet meets the specifications of the brand of magnetic Br and magnetic energy product (BH)max, otherwise, if the amount If the measured magnetic value M1/W1 is less than the magnetic value M/W obtained in step b, it is determined that the sintered NdFeB magnet does not meet the specifications of the magnetic Br and magnetic energy product (BH)max specifications of the brand; (d) it is known to meet the magnetic correction of the brand The sintered NdFeB magnet of the coercive force (iHc) specification measures the magnetic flux value M2 with a magnetic flux meter; (e) The magnet is then demagnetized with a demagnetizing coil to generate a reverse magnetic field one by one to demagnetize the sintered NdFeB magnet; (f ) After each demagnetization, use the magnetic flux measurement to measure the magnetic flux value of the magnet, and record the demagnetization magnetic field H required for the magnetic flux value to decline by 10% after demagnetization; (g) The same shape and the same brand but unknown whether it is consistent with magnetic coercion The sintered NdFeB magnet with force (iHc) specification is measured with a magnetic flux meter for the magnetic flux value M3, and then demagnetized with the demagnetizing field H obtained in step f, and then measured with the magnetic flux meter for the magnetic flux value M4, the measured M4 and M3 In comparison, if the magnetic flux decline is less than or equal to 10%, the sintered NdFeB magnet is judged to meet the grade of magnetic coercive force (iHc) specifications. On the contrary, if the magnetic flux decline is greater than 10%, the sintered NdFeB magnet is judged Does not meet the specifications of the magnetic coercive force (iHc) of the grade; and (h) Sintered NdFeB magnets with the same shape and different shapes and different shapes. If it is determined whether they meet the specifications of the magnetic coercive force (iHc) of the grade, the above steps d to f are required; The shape of the sintered NdFeB magnet may be cylindrical, pie-shaped or tile-shaped; the thickness of the sintered NdFeB magnet is 5 mm or less.

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