TWI706151B - Magnetic evaluation method of permanent magnetic ferrite magnet - Google Patents

Abstract

A magnetic evaluation method of a permanent magnetic ferrite magnet is provided and comprises steps of: providing a permanent magnetic ferrite calcined body; performing an analyzing step on the permanent magnetic ferrite calcined body to obtain an analyzing saturation magnetization of the permanent magnetic ferrite calcined body; and comparing with the analyzing saturation magnetization according to a saturation magnetization standard value in a database, wherein: when the analyzing saturation magnetization is greater than or equal to the saturation magnetization standard value, a magnetic property of a permanent magnetic ferrite magnet obtained by the permanent magnetic ferrite calcined body is determined to conforms to a standard; or when the a analyzing saturation magnetization is less than the saturation magnetization standard value, the magnetic property of a permanent magnetic ferrite magnet obtained by the permanent magnetic ferrite calcined body is determined that the standard is not conformed.

Description

Magnetic evaluation method of permanent ferrite magnet

The present invention relates to a magnetic evaluation method, in particular to a magnetic evaluation method of a permanent ferrite magnet.

In recent years, with the reduction in size, weight, and performance of electronic components, permanent ferrite magnets made of oxides are also required to have high magnetic properties. As an indicator of the magnetic properties of permanent ferrite magnets, remanence (Br) and intrinsic coercivity ( _i H _c ) are generally used as indicators. For a long time, in order to achieve the characteristics of high remanence and high intrinsic coercivity, the composition of elements in permanent ferrite magnets has been discussed.

The manufacturing process of permanent ferrite includes a sintering process. The temperature of the sintering (pre-sintering) process is higher than the sintering temperature of the magnet. In the sintering process, a fully reacted magnetic phase is required to be completed in the subsequent sintering process After achieving good magnetic properties. Therefore, in the process of producing permanent ferrite magnets, usually after the sintering process is completed, the magnetic properties of the sintered magnetic powder must be tested to evaluate the characteristics of the sintered magnetic powder. If the sintered magnetic powder has good properties, there is a better chance of achieving better magnetic properties after sintering. On the contrary, the magnetic properties of the final sintered magnet will also be poor. Therefore, the magnetic property detection of the sintered magnetic powder is very important. There are mainly two existing magnetic property detection methods, which are explained as follows.

For the first method, the magnetic properties of the magnet are evaluated by the magnetic measuring instrument (BH Tracer) mainly at the stage of the magnet being manufactured, and the performance of the calcined magnetic powder can be estimated and judged based on this data. This method requires a long detection time. For example, the fine pulverization step requires 1 to 2 working days; the sizing process of the magnetic powder slurry after the fine pulverization and the drying step of the green embryo after the magnetic powder slurry is formed in the magnetic field require 0.5 days of work Days; the sintering process of the magnet also requires 1 working day. Therefore, it takes at least 3 working days when the magnetic properties of the sintered magnet are finally measured with a magnetic measuring instrument. Although the accuracy is high in this way, because the final magnetic characteristics of the permanent ferrite magnet can be directly obtained, and then the magnetic characteristics can be used to back and accurately determine the characteristics of the permanent ferrite burned magnetic powder, but it needs to be tested The time is too long to obtain the magnetic properties results quickly, and the material formula and process conditions of the calcined magnetic powder cannot be quickly adjusted in the laboratory.

The second method is mainly to measure the magnetic properties of the calcined magnetic powder through the vibrating sample magnetometer (VSM) detection method, as an evaluation of the substitute properties of the final sintered magnet, and then based on the VSM test results Push back and revise whether the material formula and process conditions of the prepared calcined magnetic powder need to be modified. In addition, for the permanent ferrite sintered magnetic powder, the sintering step may be incomplete, resulting in a small amount of ferrite ions (Fe ²⁺ ) in the permanent ferrite sintered magnetic powder after the sintering step. Contribute to the MS value of the calcined material measured by the VSM (the unit of the MS value measured by the VSM is emu/g), but Fe ²⁺ will cause the magnetic properties of the magnet to deteriorate after the magnet is sintered. Therefore, another titration method is required to confirm the content of ferrous ions in the sintered magnetic powder. In addition, VSM instruments are expensive, so although this method can save time, it will increase the cost of the product.

Therefore, it is necessary to provide a magnetic evaluation method for permanent ferrite magnets to solve the problems existing in the conventional technology.

One object of the present invention is to provide a method for evaluating the magnetic properties of permanent ferrite magnets, by directly performing an analysis step on the sintered powder of permanent ferrite, and comparing the obtained analytical saturation magnetization with a saturation magnetization standard The difference between the values to determine whether a magnetic property of the permanent ferrite magnet obtained subsequently meets the standard. If it meets the standard, it means that the permanent ferrite sintered powder can be used to continue the process of making permanent magnet ferrite magnets; if it does not meet the standard, it means that the sintering step needs to be adjusted.

To achieve the above objective, the present invention provides a method for evaluating the magnetic properties of a permanent ferrite magnet, which includes the steps of: providing a permanent ferrite sintered powder; performing an analysis step on the permanent ferrite sintered powder to Obtain an analytical saturation magnetization of the sintered permanent magnet ferrite powder; and compare the analytical saturation magnetization according to a saturation magnetization standard value in a database, wherein: when the analytical saturation magnetization is greater than or equal to the Saturation magnetization standard value, it is judged that a magnetic property of a permanent ferrite magnet obtained by sintering powder of the permanent ferrite meets the standard; or when the analytical saturation magnetization is less than the saturation magnetization standard value, then It is judged that the magnetic properties of the permanent ferrite magnet obtained by sintering the powder of the permanent ferrite do not meet the standard.

In an embodiment of the present invention, there is a positive correlation between the analytical saturation magnetization of the permanent ferrite sintered powder and the magnetic properties of the permanent ferrite magnet.

In an embodiment of the present invention, the magnetic properties of the permanent ferrite magnet include remanence (Br), coercive force ( _b H _c ), intrinsic coercive force ( _i H _c ) and maximum magnetic energy product (( BH) at least one of _m ).

In an embodiment of the present invention, the analysis step includes: mixing 0.05 to 0.1 parts by weight of an adhesive, 0.08 to 0.12 parts by weight of a solvent, and 99.78 to 99.87 parts by weight of the permanent ferrite to burn the powder to Forming an analysis test piece; and analyzing the analysis test piece by a magnetic measuring instrument to obtain the analysis saturation magnetization.

In an embodiment of the present invention, the adhesive includes an epoxy resin and the solvent includes acetone.

In an embodiment of the present invention, the step of providing the ferrite sintered powder includes the steps of: providing a mixture, wherein the mixture includes an iron oxide powder and a strontium compound; and performing a calcining step to use the mixture Hold the temperature between 1220 and 1300 ^o C for 50 to 70 minutes to form a pre-treatment product; and perform a coarse pulverization step on the pre-treatment product so that an average particle size of the pre-treatment product is between The permanent ferrite sintered powder is formed between 2 to 5 microns.

In an embodiment of the present invention, the mixture further includes at least one of a cobalt compound and a lanthanide compound.

In an embodiment of the present invention, the step of providing the mixture further includes the step of providing an additive, wherein the additive includes at least one of calcium carbonate, silicon oxide, phosphorus pentoxide, and boron oxide.

In an embodiment of the present invention, after the step of determining that the analytical saturation magnetization is greater than or equal to the standard value of the saturation magnetization, the method further comprises a step of: performing a fine pulverization step, wherein the fine pulverization step is to pulverize the permanent magnet The ferrite sintered powder, so that the average particle size of the permanent ferrite sintered powder is between 0.65 and 0.75 microns.

In an embodiment of the present invention, after the fine pulverization step is performed, the method further includes the step of: performing a magnetic field alignment forming step on the permanent ferrite sintered powder to form an embryo body, wherein the magnetic field alignment forming step The intensity of an alignment magnetic field is between 1.3 and 1.7 Tesla, a molding pressure is between 3 and 4 tons/cm², and a molding time is between 90 and 110 seconds; and sintering step, the embryo body to a temperature between 1220 to 1240 ^o C of sintering duration between 50 and 70 minutes to prepare the hard ferrite magnets.

In order to make the above and other objects, features, and advantages of the present invention more obvious and understandable, the following will specifically cite the preferred embodiments of the present invention, together with the accompanying drawings, and describe in detail as follows. Furthermore, the directional terms mentioned in the present invention, such as up, down, top, bottom, front, back, left, right, inside, outside, side, surrounding, center, horizontal, horizontal, vertical, vertical, axial, The radial direction, the uppermost layer or the lowermost layer, etc., are only the direction of reference to the attached drawings. Therefore, the directional terms used are used to describe and understand the present invention, rather than to limit the present invention.

Please refer to Figure 1, the magnetic evaluation method 10 of a permanent ferrite magnet of an embodiment of the present invention mainly includes the following steps 11 to 13: providing a permanent ferrite sintered powder (step 11); The ferrite sintered powder is subjected to an analysis step to obtain an analysis saturation magnetization of the permanent ferrite sintered powder (step 12); and the comparison is performed according to a saturation magnetization standard value in a database Analyze the saturation magnetization, where: when the analysis saturation magnetization is greater than or equal to the standard value of the saturation magnetization, it is judged that a magnetic property of a permanent ferrite magnet obtained by the permanent ferrite sintering powder system meets the standard Or when the analytical saturation magnetization is less than the standard value of the saturation magnetization, it is determined that the magnetic properties of the permanent ferrite magnet obtained by the permanent ferrite sintered powder system do not meet the standard (step 13). In the present invention, the implementation details and principles of the above steps of the embodiments will be described in detail below one by one.

The magnetic evaluation method 10 of a permanent ferrite magnet of an embodiment of the present invention first includes step 11: providing a permanent ferrite sintered powder. In this step 11, the sintered powder of the permanent ferrite can be prepared, for example, by the following steps: providing a mixture, wherein the mixture includes iron oxide powder and a strontium compound; performing a calcination step, using 1220 Hold the temperature between 1300 ^o C for 50 to 70 minutes to form a pre-treatment product; and perform a coarse pulverization step on the pre-treatment product so that an average particle size of the pre-treatment product is 2 The permanent magnet ferrite sintered powder is formed between 5 microns. In one embodiment, the mixture includes iron oxide powder and a strontium compound. In this step 11, the iron oxide powder can be, for example, a commercially available product, or a by-product produced in a steel manufacturing process. For example, the iron rust generated on the surface of the iron needs to be removed when the steel is hot processed. It can be used as the source of the iron oxide powder. In one embodiment, the strontium compound may include strontium carbonate, for example. It is worth mentioning that the provided mixture is mainly used to generate strontium ferrite magnetic powder. The calcination step is mainly used to make the mixture react at a high temperature to make the pre-treatment material conform to the molecular formula of the strontium ferrite magnetic powder. In one embodiment, a molecular formula of the pretreatment is SrO. nFe ₂ O ₃ , where n is between 5 and 6. In another embodiment, an atmosphere during the calcination step contains 5% oxygen.

In one embodiment, the mixture may further include at least one of a cobalt compound and a lanthanide compound. Specifically, the cobalt element in the cobalt compound or the lanthanum element in the lanthanide compound contributes to the permanent ferrite magnet made of modified ferrite powder to obtain higher remanence (Br), Coercivity ( _i H _c ) and squareness (Hk/ _i H _c ). In an example, the cobalt compound is, for example, cobalt oxide (Co ₃ O ₄ ). In another example, the lanthanide is, for example, lanthanum oxide (La ₂ O ₃ ). In this embodiment, a molecular formula (Sr ²⁺ _1-x La _3+x )O. n(Fe ³⁺ _12-y Co ²⁺ _y ) ₂ O ₃ , where n is between 7 and 9, and x=2ny, where x=2ny is required when La and Co elements replace Sr and Fe respectively Meet the electrical neutrality conditions. In a specific example, x may be between 0.15 and 0.16, for example. In one embodiment, the cobalt compound may be added in the adding step described later.

In one embodiment, before the step 11 of providing the mixture and the step 12 of the calcination, it further comprises a dehydration step of the mixture, wherein the moisture content of the mixture after the dehydration step is between 18% and 24%. %between.

The magnetic evaluation method 10 of a permanent ferrite magnet of an embodiment of the present invention is followed by step 12: performing an analysis step on the permanent ferrite sintered powder to obtain an analysis of the permanent ferrite sintered powder Saturation magnetization. In this step 12, the analysis step may include mixing 0.05 to 0.1 parts by weight of an adhesive, 0.08 to 0.12 parts by weight of a solvent, and 99.78 to 99.87 parts by weight of the permanent ferrite powder to form an analysis. Test piece; and analyzing the analysis test piece by a magnetic measuring instrument to obtain the analysis saturation magnetization. In one embodiment, the magnetic measurement instrument is, for example, a commercially available instrument (NIM-2000 BH Loop Tracer of the Chinese Academy of Metrology). In another embodiment, the analysis test piece is, for example, in the shape of a round cake (for example, 1 cm in diameter and greater than 0.7 cm in thickness), and the thickness of the analysis test piece needs to be higher than the height of the coil used for testing by a commercially available instrument, such as the The height of the coil is about 0.5 cm). In another embodiment, the adhesive includes an epoxy resin and the solvent includes acetone. Before the step of analyzing the test strip and analyzed after a further embodiment, the step of forming the test strip, the test strip can be baked in the oven for about 2 hours to 100 ^o C, to remove excess moisture.

The magnetic evaluation method 10 of a permanent ferrite magnet according to an embodiment of the present invention is finally step 13: compare the analysis saturation magnetization according to a saturation magnetization standard value in a database, wherein: when the analysis saturation magnetization is greater than Or equal to the standard value of saturation magnetization, it is judged that a magnetic property of a permanent ferrite magnet obtained by sintering powder of the permanent ferrite meets the standard; or when the analytical saturation magnetization is less than the saturation magnetization standard Value, it is judged that the magnetic properties of the permanent ferrite magnet obtained by the permanent ferrite sintered powder system does not meet the standard. In this step 13, the standard value of saturation magnetization in the database can be confirmed through experiments, for example. Specifically, a plurality of sintered permanent ferrite powders are produced first, and the saturation magnetization of the sintered permanent ferrite powders is measured (for example, refer to the production method of step 12). Next, the sintered powders of the permanent ferrites are respectively made into permanent ferrite magnets, and measured with a magnetic measuring instrument to measure the magnetic properties of the permanent ferrite magnets. Finally, determine whether the magnetic properties of the permanent ferrite magnets have characteristics that meet the standards (for example, commercial standards or international standards (such as JIS C2501 or JIS C2502, etc.). If they meet the standards, the corresponding permanent magnets can be The saturation magnetization of the sintered powder is taken as the standard value.

On the other hand, according to the above method, the inventor of the present case learned that the analytical saturation magnetization of the permanent ferrite sintered powder has a positive correlation with the magnetic properties of the permanent ferrite magnet. Therefore, if the magnetic properties of these permanent ferrite magnets include both conforming to the standard and not conforming to the standard, mathematical theory can be used to infer that the value of the saturation magnetization of the permanent ferrite sintered powder corresponds to the permanent magnet What is the standard value of the magnetic properties of the ferrite magnet? For example, for example, the saturation magnetization of two different permanent ferrite sintered powders is 1400 Gauss (Gauss; abbreviated as G) and 1600 G, and these two different permanent ferrite sintered powders are made The permanent magnet ferrite magnets obtained have remanence of 4200G and 4800G, respectively. And if the commercial standard value of permanent ferrite magnet is at least 4500G, it can be inferred that if the saturation magnetization of the permanent ferrite sintered powder is greater than or equal to 1500G, the permanent ferrite magnet produced should be approximately Falling on 4500G. It is worth mentioning that in addition to this characteristic of remanence, other magnetic properties such as coercive force ( _b H _c ), intrinsic coercive force ( _i H _c ) and maximum magnetic energy product ((BH) _m ) also have similar properties The positive correlation. Therefore, after the above method, a database can be created. In addition, various databases can be established according to different mixtures, different manufacturing processes, or different specific gravity, etc., to facilitate magnetic evaluation at any time.

It can be seen from the above that the magnetic evaluation method of the permanent ferrite magnet of the embodiment of the present invention can judge whether the magnetic properties of the permanent ferrite magnet obtained subsequently conform to the saturation magnetization standard value of the saturation magnetization. standard. In addition, because this analysis method can know in advance whether the magnetic properties of the permanent ferrite magnets obtained later meet the standards without the need for fine pulverization, drying, and sintering steps, it can save time and cost. . Furthermore, this method does not require the use of VSM equipment, so it can also save the production cost of the product. In addition, since the unit of analyzing the saturation magnetization in the magnetic evaluation method of the permanent ferrite magnet of the embodiment of the present invention is the same as the unit of the magnetic characteristic Br of the finally obtained magnet, no conversion is required. Therefore, the evaluation method is relatively simple and can be used as the alternative characteristic of permanent ferrite.

Several examples and comparative examples are listed below to prove that the magnetic evaluation method of the permanent ferrite magnet of the examples of the present invention does have the above-mentioned effects.

Example 1

First, the main raw material iron oxide powder (Fe ₂ O ₃ ) and another main raw material strontium carbonate (SrCO ₃ ) are blended with the basic composition of SrO·nFe ₂ O ₃ (n=5.9), and 4.9wt% of After the trace additive La ₂ O ₃ and water are mixed, the mixture is mixed and milled with a commercially available ball mill (Ball Mill) with a weight ratio of 1:5 for 2 hours, and then the material is discharged to obtain a mixture in a slurry state. The steel ball is 3/16 in diameter. Inch chromium-free bearing steel balls. Next, the above-mentioned mixture is dehydrated with a commercially available air filter press, and the moisture content of the dehydrated mixture is about 21±3%.

Next, the dehydrated mixture is subjected to a calcination step. Preheat the mixture with a commercially available dryer, where the temperature of the dryer is 300 ± 10 ^o C, the temperature holding time is 30 to 40 minutes, and the moisture content of the mixture after drying is less than 2%. After that, the mixture is calcined in a commercially available rotary kiln to form a pre-treatment material. The calcination temperature is about 1230 ^o C, the calcination time is 1 hour, and the oxygen content in the rotary kiln is about 5%. After calcination, the size of the processed material is between 0.5 cm and 1 cm.

The processed material before being calcined in the rotary kiln is sent to the cooling barrel for cooling through the slide pipe connected with the rotary kiln. When the temperature of the pre-treatment material drops below 90 ^o C, a coarse pulverization step is carried out by a Roller Mill equipped with a wind separation function of a cyclone collector to obtain the permanent ferrite sintered powder, in which the permanent magnet The average particle size of the sintered oxygen powder is about 2 to 5 microns.

A commercially available instrument (NIM-2000 BH Loop Tracer of the Chinese Academy of Metrology) was used to detect the substitution characteristics of a part of the braised magnetic powder. The details are as follows: the permanent magnet ferrite of 99.78 to 99.87 parts by weight is sintered powder, 0.05 to 0.1 parts by weight of epoxy resin (Epoxy) is mixed as an adhesive, and 0.1 part by weight of acetone is added as a solvent during the mixing process. After mixing and stirring, it is manually dry-formed into a round cake-shaped test piece (for example, a diameter of 1 cm and a thickness of more than 0.7 cm). After that, the test piece was baked in an oven at about 100 ^o C for about 2 hours, and then the saturation magnetization (Saturation Magnetisation, Js, in Gauss) of the test piece was measured with a commercially available instrument, and the measured JS The value is 1560G.

After that, add additives (such as Co ₃ O ₄ , CaCO ₃ , SiO ₂ or B ₂ O ³ ) to the remaining part of the sintered magnetic powder, and use a ball mill with a weight ratio of 1:12 for wet grinding. A further fine pulverization step is performed for 25 hours, so that the average particle size of the modified ferrite magnetic powder is about 0.65 to 0.75 microns, and the steel ball is a chromium-free bearing steel ball with a diameter of 3/16 inches.

Next, proceed to the (wet) magnetic field alignment molding step, using a commercially available 25-ton semi-automatic wet magnetic field molding machine to perform magnetic field alignment molding on the permanent ferrite sintered powder, the alignment magnetic field intensity is 1.5 Tesla (Telsa), the molding pressure is 3.5 tons/square centimeter (Ton/cm ² ), and the size of the embryo body is a tile-shaped embryo body with a length of 6 cm, a width of 4 cm, an arch height of 2 cm, and a thickness of about 0.7 cm.

Finally, a sintering step, the embryo temperature of 1240 ^o C for 60 minutes continuous sintering, to produce the ferrite permanent magnet. The magnetic properties of the permanent ferrite magnet were tested with a commercially available instrument (NIM-2000 BH Loop Tracer of the Chinese Academy of Metrology), as described in Table 1 below.

Table I Braised magnetic powder material formula Simmering temperature ( ^o C) Saturation magnetization of sintered powder Sintering temperature ( ^o C) Magnetic properties of magnets B _{r b} H _c i H _c ( BH ) _m Fe/Sr mol ratio La ₂ O ₃ (wt%) J _S (G) (G) (Oe) (Oe) (MGOe) Example 1 5.9 4.9 1230 1560 1235 4230 4132 4358 4.42 Example 2 5.9 4.9 1250 1652 1235 4385 4213 4425 4.56 Example 3 5.9 4.9 1270 1785 1235 4528 4362 4556 4.68 Example 4 5.9 3.0 1270 1610 1235 4295 4163 4390 4.47

Examples 2 to 4

The manufacturing methods of Examples 2 to 4 are similar to that of Example 1, but the difference lies in the different composition ratios and different sintering temperatures, which can be referred to Table 1 above.

From Table 1 above, it can be seen that the analytical saturation magnetization of the permanent ferrite sintered powder in Examples 1 to 4 is indeed the same as the magnetic properties of the permanent ferrite magnet obtained by the permanent ferrite sintered powder system. Positive correlation. When the saturation magnetization is analyzed, the magnetic properties of the permanent ferrite magnet (such as remanence (Br), coercive force ( _b H _c ), intrinsic coercive force ( _i H _c ) or maximum magnetic energy product (( BH) _m )) is also higher. In other words, the magnetic evaluation method of the permanent ferrite magnet of the embodiment of the present invention can compare the saturation magnetization of the analysis according to the saturation magnetization standard value to determine whether the magnetic properties of the permanent ferrite magnet obtained subsequently meet the standard. .

In addition, it should be mentioned that the magnetic evaluation method of the embodiment of the present invention is suitable for the evaluation of the magnetic properties of permanent magnet ferrite, but cannot be applied to soft magnetic materials.

Although the present invention has been disclosed in preferred embodiments, it is not intended to limit the present invention. Anyone who is familiar with the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be subject to the scope of the attached patent application.

10: method

11~13: Steps

FIG. 1 is a block diagram of the magnetic evaluation method of a permanent ferrite magnet according to an embodiment of the present invention.

10: method

11~13: Steps

Claims (9)

A method for evaluating the magnetic properties of a permanent ferrite magnet, comprising the steps of: providing a permanent ferrite sintered powder; performing an analysis step on the permanent ferrite sintered powder to obtain the permanent ferrite sintered powder An analysis of the saturation magnetization of the magnetic body, wherein the analysis step includes: mixing 0.05 to 0.1 parts by weight of an adhesive, 0.08 to 0.12 parts by weight of a solvent, and 99.78 to 99.87 parts by weight of the permanent ferrite to burn the powder to Forming an analysis test piece; and analyzing the analysis test piece by a magnetic measurement instrument to obtain the analysis saturation magnetization; and according to a saturation magnetization standard value ratio in a database to the analysis saturation magnetization, wherein: When the analytical saturation magnetization is greater than or equal to the standard value of the saturation magnetization, it is judged that a magnetic property of a permanent ferrite magnet obtained by the permanent ferrite sintered powder system meets the standard; or when the analytical saturation magnetization If the intensity is less than the standard value of saturation magnetization, it is judged that the magnetic properties of the permanent ferrite magnet obtained by sintering the permanent ferrite powder does not meet the standard. The magnetic evaluation method of a permanent ferrite magnet according to claim 1, wherein there is a positive correlation between the analytical saturation magnetization of the permanent ferrite sintered powder and the magnetic properties of the permanent ferrite magnet relationship. The magnetic evaluation method of a permanent ferrite magnet according to claim 1, wherein the magnetic properties of the permanent ferrite magnet include remanence (Br), coercivity ( _b H _c ), and intrinsic coercivity ( _i At least one of H _c ) and maximum magnetic energy product ((BH) _m ). The magnetic evaluation method of a permanent ferrite magnet according to claim 1, wherein the adhesive includes an epoxy resin and the solvent includes acetone. The magnetic evaluation method of a permanent ferrite magnet according to claim 1, wherein the step of providing the sintered powder of the permanent ferrite includes the step of providing a mixture, wherein the mixture includes iron oxide powder and a strontium compound; Carry out a calcination step, hold the mixture at a temperature between 1220 to 1300°C for 50 to 70 minutes to form a pre-treatment product; and perform a coarse crushing step on the pre-treatment product to make the pre-treatment The average particle size of the material is between 2 and 5 microns to form the permanent ferrite sintered powder. The magnetic evaluation method of a permanent ferrite magnet according to claim 5, wherein the mixture further contains at least one of a cobalt compound and a lanthanide compound. The magnetic evaluation method of a permanent ferrite magnet according to claim 5, wherein the step of providing the mixture further includes the step of: providing an additive, wherein the additive includes calcium carbonate, silicon oxide, phosphorus pentoxide, and oxide At least one of boron. The magnetic evaluation method of a permanent ferrite magnet according to claim 5, wherein after the step of judging that the analytical saturation magnetization is greater than or equal to the saturation magnetization standard value, the method further includes the step of: performing a fine pulverization step, wherein the The fine pulverization step is to pulverize the sintered permanent ferrite powder so that an average particle size of the sintered permanent ferrite powder is between 0.65 and 0.75 microns. The method for evaluating the magnetic properties of a permanent ferrite magnet according to claim 8, wherein after the fine pulverization step, the method further includes the step of: performing a magnetic field alignment forming step on the permanent ferrite sintered powder to form a The embryo body, wherein an alignment magnetic field intensity of the magnetic field alignment forming step is between 1.3 to 1.7 Tesla, and a forming The pressure is between 3 to 4 tons/cm², and a molding time is between 90 and 110 seconds; and a sintering step is performed, and the green body is maintained at a temperature between 1220 and 1240°C Sintering takes between 50 to 70 minutes to obtain the permanent ferrite magnet.

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