TWI636032B - Method for manufacturing gyromagnetic element - Google Patents

Abstract

The invention provides a method for manufacturing a rotating magnet, comprising the steps of: providing a gyromagnetic material; performing a first ball milling step on the gyromagnetic material to obtain a gyromagnetic powder; after the first ball milling step, the gyromagnetic material The powder is subjected to a calcining step; after the calcining step, a second ball milling step is performed on the gyromagnetic powder; after the second ball milling step, the diamagnetic powder is subjected to an annealing step; after the annealing step, Performing a third ball milling step on the gyromagnetic powder; after the third ball milling step, performing a cold press forming step on the gyromagnetic powder to press the gyromagnetic powder into a blank; and at 1350 to 1450 The blank is subjected to a sintering step at a temperature of ° C and oxygen to form a rotating magnet.

Description

 Spinning magnet manufacturing method  

The present invention relates to a method for manufacturing a rotating magnet, and more particularly to a method for manufacturing a yttrium iron garnet (YIG)-based rotating magnet suitable for the 2 to 4 GHz frequency band.

In recent years, the demand for radar, satellite and other technologies has made the development of gyromagnetic materials and components in the microwave field more and more important. Yttrium garnet (YIG) gyromagnetic material is widely used because of its wide variation range of saturation magnetization at room temperature, high angular ratio, low coercive force, high Curie temperature and good temperature stability. In the microwave components such as the latching phase shifter and the circulator. These garnet-based (Garnet) microwave components are mainly used in wireless communication fields such as Minsheng mobile phone base stations and military radars.

The gyromagnetic materials currently used in microwave components used in the 2~4GHz frequency band generally have the following problems: (1) the saturation magnetization (4π M _s ) is not easily adjusted to the appropriate value of the phase shifter; (2) it is not easy to achieve at the same time. The saturation magnetization, the angular ratio, and the coercive force required by the phase shifter tend to be lost. There have been some studies, such as U.S. Patent Nos. 3,132,105 and 5,055,214, which suggest that ruthenium (Gd) can be doped in Garnet's gyromagnetic material to achieve the desired magnetic properties simultaneously, but the ruthenium element will make the overall cost of the phase shifter A substantial increase.

Therefore, it is necessary to provide a method of manufacturing a rotating magnet to solve the problems of the conventional technology.

The main object of the present invention is to provide a method for manufacturing a rotating magnet. The yttrium iron garnet containing a specific proportion of manganese aluminum is firstly homogenized by a ball milling step after simmering, and then an annealing step is performed to make the material powder. The smaller grains in the body can be grown to a larger size, and then the ball milling step is performed again to refine the grains grown after annealing. After the above treatment, the yttrium iron garnet-based gyromagnetic material can obtain the magnetic characteristics required for the microwave component suitable for the 2 to 4 GHz frequency band with low cost and simple steps.

In order to achieve the above object, an embodiment of the present invention provides a method for manufacturing a rotating magnet, comprising the steps of: providing a gyromagnetic material; performing a first ball milling step on the gyromagnetic material to obtain a gyromagnetic powder; After the first ball milling step, the skeletal magnetic powder is subjected to a calcining step; after the sintering step, the spheroidal magnetic powder is subjected to a second ball milling step; after the second ball milling step, the gyromagnetic powder is subjected to An annealing step; after the annealing step, performing a third ball milling step on the gyromagnetic powder; after the third ball milling step, performing a cold press forming step on the gyromagnetic powder to press the spheroidal powder a blank member; and subjecting the blank to a sintering step at a temperature of 1350 to 1450 ° C and oxygen to form a rotating magnet.

In an embodiment of the invention, the gyromagnetic material comprises Y _3+z (Mn _x Al _yx Fe _1-y ) _5-z O ₁₂ in a molar number, wherein x=0.018~0.046, y=0.1~ 0.2, z = -0.04 to 0.04.

In one embodiment of the invention, the first ball milling step is ball milling using zirconia beads for 1-3 hours.

In one embodiment of the invention, the temperature of the calcining step is from 1150 to 1250 ° C for 1 to 3 hours.

In one embodiment of the invention, the second ball milling step is ball milling using zirconia beads for 1-3 hours.

In an embodiment of the invention, the annealing step is performed in the air at 800 to 900 ° C for 0.5 to 1 hour.

In one embodiment of the invention, the third ball milling step is ball milling using zirconia beads for 0.5 to 1 hour.

In one embodiment of the invention, the cold press forming step does not use an organic binder.

In an embodiment of the invention, the sintering step is carried out for a period of 5 to 7 hours.

In one embodiment of the invention, the rotating magnet has a saturation magnetization of 700 ± 5% Gauss, a coercive force of less than 0.4 Oe, and an angular ratio of greater than 0.85.

1A to 1D are graphs showing the tendency of crystal grains observed by the metallographic microscope of the experimental groups 6, 7, 10 and 12 according to an embodiment of the present invention.

The above and other objects, features, and advantages of the present invention will become more apparent from In addition, the singular forms "a," "," For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof; "%" as referred to in the present specification means "percent by weight (wt%)" unless otherwise specified; For example, 10% to 11% of A) include upper and lower limits (ie, 10% ≦A ≦ 11%) unless otherwise specified; if the value range does not define a lower limit (such as less than 0.2% of B, or 0.2) B) below B) means that the lower limit may be 0 (ie 0% ≦ B ≦ 0.2%); the proportional relationship of the "weight percentage" of each component may also be replaced by the proportional relationship of "parts by weight". The above terms are used to illustrate and understand the present invention and are not intended to limit the invention.

An embodiment of the invention provides a method for manufacturing a rotating magnet, comprising the steps of: (S1) providing a gyromagnetic material; (S2) performing a first ball milling step on the diamagnetic material to obtain a gyromagnetic powder; (S3) a sintering step of the gyromagnetic powder; (S4) performing a second ball milling step on the gyromagnetic powder; (S5) performing an annealing step on the diamagnetic powder; (S6) performing a annealing step on the diamagnetic powder a third ball milling step; (S7) after the third ball milling step, performing a cold press forming step on the gyromagnetic powder to press the gyromagnetic powder into a blank; and (S8) at 1350 to 1450 ° C The preform is subjected to a sintering step in a temperature and oxygen to form a rotating magnet.

Preferably, in the step (S1), the gyromagnetic material comprises Y _3+z (Mn _x Al _yx Fe _1-y ) _5-z O ₁₂ in a molar number, wherein x=0.018~0.046, y =0.1~0.2, z=-0.04~0.04. Further, the gyromagnetic material belongs to the yttrium iron garnet, and is formed by substituting a part of iron element with aluminum (Al) and manganese (Mn).

In this step (S2), the first ball milling step is ball milling using zirconia beads for 1 to 3 hours, which may be, for example, 1, 1.5, 2, 2.5 or 3 hours, but is not limited thereto.

In this step (S3), the temperature of the calcination step is 1150 to 1250 ° C, which may be, for example, 1150, 1200 or 1250 ° C, but is not limited thereto. The calcination step is carried out for 1 to 3 hours, and may be, for example, 1, 1.5, 2, 2.5 or 3 hours.

In this step (S4), the second ball milling step is ball milling using zirconia beads for 1 to 3 hours, which may be, for example, 1, 1.5, 2, 2.5 or 3 hours, but is not limited thereto.

In this step (S5), the annealing step is carried out in the air at 800 to 900 ° C for 0.5 to 1 hour.

In this step (S6), the third ball milling step is ball milling using zirconia beads for 0.5 to 1 hour.

In this step (S7), the cold press forming step does not additionally use an organic binder (i.e., excludes any use of any organic binder), and/or does not use the remaining additives.

In this step (S8), the sintering step is carried out for 5 to 7 hours, and may be, for example, 5, 5.5, 6, 6.5 or 7 hours, but is not limited thereto. Preferably, the rotating magnet has a saturation magnetization of 700 ± 5% Gauss, a coercive force of less than 0.4 Oe, and an angular ratio of more than 0.85.

In order to verify that the method for manufacturing a rotating magnet of the present invention can effectively improve the magnetic properties of the rotating magnet, various conditions are tested. The material composition and experimental conditions of the experimental group are shown in Table 1 below.

The manufacturing process of each group of rotating magnets in Table 1 is as follows:

(1) Spinning material:

The molecular formula is Y _3+z (Mn _x Al _yx Fe _1-y ) _5-z O ₁₂ , where z is the adjustment term of the iron-depleted (lower iron element) of the material, and the higher the z, the less the iron element; x, y, z The values are the values for each group shown in Table 1 above; the number of anionic charges (provided by O) is -24, and the number of cationic charges (provided by Y, Mn, Al, Fe) is +24.

(2) First ball milling step:

The material in (1) was ball milled in a ball mill for 1 to 3 hours using zirconia beads. This step is to allow the various materials to be sufficiently uniformly dispersed.

(3) Simmering:

The powder obtained in (2) was calcined in air at 1200 ° C for 1 to 3 hours at a rate of 5 ° C per minute.

(4) Second ball milling step:

The calcined material obtained in (3) is ball-milled in a vibrating mill using zirconia beads for 1 to 3 hours, so that the calcined powder has a desired particle size range, and may be, for example, 1 μm to 1.5 μm.

(5) Annealing:

The powder obtained in (4) is annealed in air at 800 to 900 ° C for 0.5 to 1 hour, so that the fine powder can be grown again to avoid generation of giant crystals in the subsequent sintering process.

(6) Third ball grinding step:

The annealed material obtained in (5) is ball-milled in a vibrating mill using zirconia beads for 0.5 to 1 hour, so that the particle size of the larger crystal grains excessively grown during the annealing process is reduced, so that the overall powder particle size is reduced. narrow range distribution segment is formed, the grain growth during the sintering process to improve the chance of desired dimensions, thereby enabling tissue formation material microstructure fine grains can be reduced ferromagnetic resonance linewidth gyromagnetic material (△ H) and Dielectric loss (tan δ _e ).

(7) Forming:

The powder obtained in (6) was pressed into a blank by a "cold isostatic pressing" (CIP) without adding any organic binder.

(8) Sintering step:

The blank obtained in (7) is placed in a sintering furnace and densely sintered at T ° C for 5-7 hours in an oxygen atmosphere at a temperature rising rate of 4 ° C per minute; the cooling temperature is lowered from the highest temperature to 1250 ° C, and the cooling rate is per Minute 3 ° C; from 1250 ° C to 200 ° C, the cooling rate is 5 ° C per minute, to 200 ° C below the natural cooling.

(9) Magnetic property measurement:

The magnetic rod obtained in (6) is ground to a desired diameter by a centerless grinding machine to facilitate subsequent processing into various magnetic material samples for measuring saturation magnetization (4π M _s ), residual magnetization ( B _r ), and correction. Coercivity ( H _c ), squareness ratio ( B _r /4π M _s ), ferromagnetic resonance linewidth (Δ H ), dielectric constant (ε), dielectric loss (tan δ _e ), sintered density ( d ) and Curie temperature ( T _c ). The above saturation magnetization (4π M _s ), residual magnetization ( B _r ), coercive force ( H _c ), and angular ratio ( B _r /4π M _s ) are Japanese Yokogawa SK-130B-H tracer analyzer It is measured; the Curie temperature ( T _c ) is measured by TH2828 and muffle furnace; the ferromagnetic resonance line width (Δ H ), dielectric constant (□), and dielectric loss (tan δ _e ) are based on “IEC60556”. The measurement method was measured; the sintered density was measured by the drainage method.

It can be seen from Table 2 that by adjusting the ratio of Mn, Al, and Fe elements in the gyromagnetic material (experimental groups 1 to 5), the magnetic properties of the gyromagnetic material can be affected, and the magnetic properties obtained by the experimental group 2 are the closest. Requirements for microwave components in the 2~4GHz band; by different sintering temperatures (experimental groups 6~7), it is found that the magnetic properties required for microwave components in the near 2~4GHz band can be obtained at 1450 °C; by adjusting Y and Fe The content ratio (experimental group 8~11, changing the value of z), can be found that when z is 0.02 (experimental group 10) has the magnetic characteristics required by the microwave components in the frequency band of 2~4 GHz; in the experimental group 12, it is verified. Taking the third ball milling step and annealing, the highest angular ratio (about 0.90), the lowest coercive force (0.32Oe), the lowest dielectric loss (11.6×10 ^-5 ), the lowest ferromagnetic resonance line width (31Oe) and saturation can be obtained. The magnetization is about 702 Oe.

Next, please refer to Figures 1A to 1D, which show the trends of grain changes observed by metallographic microscopes in experimental groups 6, 7, 10, and 12, respectively. From the comparison of the 1A and 1B graphs, it can be found that the experimental groups 6 and 7 have different grain sizes due to different sintering temperatures. When the sintering temperature is increased from 1350 °C to 1450 °C, the grains have a significant growth tendency. It can also be seen from the comparison of Figures 1B and 1C that the iron-deficient formula of the experimental group 10 did not have a significant effect on the grain size. Furthermore, it can be seen from the 1DD that after the annealing and the third ball milling step of the experimental group 12, the grain distribution can be uniformized after sintering, and the magnetic properties of the rotating magnet can be further optimized to meet the frequency of 2 to 4 GHz. The range of microwave components required.

The present invention has been disclosed in its preferred embodiments, and is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

Claims (9)

A method for manufacturing a rotating magnet, comprising the steps of: providing a gyromagnetic material, wherein the gyromagnetic material comprises Y _3+z (Mn _x Al _yx Fe _1-y ) _5-z O ₁₂ in a molar ratio, wherein x=0.018~0.046, y=0.1~0.2, z=-0.04~0.04; performing a first ball milling step on the gyromagnetic material to obtain a gyromagnetic powder; after the first ball milling step, the gyromagnetic powder Performing a calcining step; after the calcining step, performing a second ball milling step on the gyromagnetic powder; after the second ball milling step, performing an annealing step on the gyromagnetic powder; and after the annealing step, Performing a third ball milling step on the gyromagnetic powder; after the third ball milling step, performing a cold press forming step on the gyromagnetic powder to press the gyromagnetic powder into a blank; and at 1350 to 1450 The blank is subjected to a sintering step at a temperature of ° C and oxygen to form a rotating magnet. The method for producing a rotating magnet according to claim 1, wherein the first ball milling step is ball milling using zirconia beads for 1 to 3 hours. The method for producing a rotating magnet according to claim 1, wherein the temperature of the calcining step is 1150 to 1250 ° C for 1 to 3 hours. The method for producing a rotating magnet according to claim 1, wherein the second ball milling step is ball milling using zirconia beads for 1 to 3 hours. The method for producing a rotating magnet according to claim 1, wherein the annealing step is performed in the air at 800 to 900 ° C for 0.5 to 1 hour. The method for manufacturing a rotating magnet according to claim 1, wherein the method The third ball milling step is ball milling using zirconia beads for 0.5 to 1 hour. The method for producing a rotating magnet according to claim 1, wherein the cold press forming step does not use an organic binder. The method for producing a rotating magnet according to claim 1, wherein the sintering step is performed for 5 to 7 hours. The method of manufacturing a rotating magnet according to claim 1, wherein the rotating magnet has a saturation magnetization of 700 ± 5% Gauss, a coercive force of less than 0.4 Oe, and an angular ratio of more than 0.85.