Metal powder tape casting slurry as well as preparation method and application thereof

Abstract

The invention discloses metal powder tape casting slurry and a preparation method and application thereof, belongs to the field of metal inductors and manufacturing thereof, and prepares a Fe-Si series metal diaphragm which is high in slurry solid content (greater than 90%), compact in tape casting diaphragm and free of holes by adding an organosiloxane polymer and adjusting the proportion of a dispersing agent to a binder. The thickness of the Fe-Si series metal diaphragm is adjustable within 20-100 microns, the diaphragm density is 4.9 g / cm < 3 >, the magnetic conductivity after sintering exceeds 50 (1MHz), and the Fe-Si series metal diaphragm can be suitable for diaphragm preparation of a metal powder inductor. The preparation method is simple and easy for mass production.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of metal inductors and manufacturing thereof, and proposes a Fe-Si system metal powder casting film preparation method. BACKGROUND

[0002] The mainstream inductors in the early stage mainly adopt ferrite materials, but with the development trend of small size, low voltage and large current of power modules, the ferrite materials are restricted by the low saturation magnetic flux density and other conditions, and it is difficult to meet the subsequent development needs. The basic characteristics of metal magnetic powder core are high Bs, and it is not easy to produce saturation in the production of DC output rectifier filter choke under large current, has good constant permeance characteristics, and the Curie temperature of metal powder is high, the permeability changes little in the working range, and the reliability is high. The chip inductor developed based on metal soft magnetic material has excellent advantages in inductance value, direct current resistance, frequency response and other aspects, and is more suitable for artificial intelligence, new energy vehicles, AI computing servers, communication power supplies, notebook computers, mining machines and other high computing power application scenarios.

[0003] However, with the further requirement of miniaturization, the common one-piece metal inductor is restricted by the conditions of equipment and process and cannot be prepared into smaller size such as 1005 (length: 1.0 mm, width: 0.5 mm, height 0.5 mm). The low-temperature co-fired ceramic (LTCC) lamination technology can better produce miniaturized inductors due to its compact structure. To realize the LTCC process of metal inductors, it is necessary to develop the formula of metal powder casting slurry, obtain a dense, non-film, appearance without scratches, holes, and uniform thickness of the metal film, and ensure that it has high density and permeability. However, the morphology, density and surface characteristics of metal powder and ceramic powder used in LTCC are very different, and the formula development is difficult, and so far no relevant reports have been found. SUMMARY

[0004] In view of the above problems, the application provides a Fe-Si system metal powder casting film preparation method.

[0005] The Fe-Si system metal powder slurry formula provided by the application has high solid content (> 90%), the thickness of the metal film is adjustable in the range of 20-100um, the density of the film is up to 4.9g / cm 3 , and the permeability of the film after sintering is more than 50 (1MHz), which can be applied to the preparation of metal powder inductors.

[0006] The preparation method is as follows, and the proportions mentioned below are mass ratios: Step 1, Fe-Si system powder, dispersing agent, organosiloxane polymer and solvent are prepared according to 100:0.5-3:1:40 (mass ratio); Step 2, the ingredients prepared in step 1 are loaded into a ball mill tank with zirconium oxide balls as grinding medium, and ball milling is carried out for 10-12 hours at a powder: zirconium ball ratio of 1:2 (mass ratio) and a ball mill speed of 50-70 rpm (preferably 60 rpm) ; Step 3, the binder and plasticizer are added to the solvent in a ratio of 1:2-4, and water bath stirring is carried out for dissolution, with a water bath temperature of 50-80℃, and after complete dissolution, cooling to room temperature is carried out; Step 4, the binder and plasticizer dissolved in step 3 are added to the ball mill tank after completion of step 2, and ball milling is carried out again for 12 hours. The Fe-Si system powder, binder and plasticizer are in a ratio of 100:3-8:2.

[0007] Step 5, the slurry after completion of step 4 is filtered through a 400 mesh filter screen, and vacuum defoaming is carried out; Step 6, the slurry in step 5 is cast on a casting machine, with a casting temperature of 50-80℃, a casting knife edge controlled at 20um-100um, and a casting belt speed of 0.5-1.5m / min; Step 7, the film in step 6 is laminated, with a lamination pressure of 80T and a lamination temperature of 65-75℃. The laminated bar is cut into magnetic rings, and hydrogen degassing is carried out at 390-410℃ (preferably 400℃) for 2 hours, and hydrogen sintering is carried out at 790-810℃ (preferably 800℃) for 30-60min, to obtain a metal powder matrix.

[0008] Further, the Fe-Si system metal powder in step 1 is Fe-Si-Al, Fe-Si-Cr, the dispersant is AD-3172M, and the organosiloxane polymer is DOWSIL™ OP-8550; Further, the solvents in step 1 and step 3 are anhydrous ethanol and acetone, respectively, with a ratio of 80:20; Further, the binder in step 3 is polyvinyl butyral with a molecular weight of 170000-250000, and the plasticizer is dioctyl phthalate.

[0009] The present application prepares a Fe-Si system metal film with high slurry solid content, dense and pore-free cast film, and a magnetic permeability of more than 50 after sintering, by increasing the organosiloxane polymer, adjusting the dispersant and binder ratio. The preparation method is simple and easy to mass produce. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 It is a 20 times optical microscope photograph (left) and a 1000 times scanning electron microscope micrograph (right) of the cast film of Example 2. DETAILED DESCRIPTION

[0011] The application will be further described in detail below with reference to the accompanying drawings and examples.

[0012] Example 1 A Fe-Si-Cr metal powder tape casting film preparation method comprises: Step 1, Fe-Si-Cr powder, dispersant, organosiloxane polymer, solvent are prepared according to 100:0.5:1:40 (mass ratio); Step 2, the prepared ingredients in step 1 are loaded into a ball mill tank, zirconia balls are used as grinding medium, and the powder: zirconia ball is 1:2 (mass ratio) for ball milling for 12 hours, and the ball mill speed is 60 rpm; Step 3, the binder and plasticizer are added to the solvent in a ratio of 1:2 for water bath stirring and dissolution, the water bath temperature is 70℃, and after complete dissolution, it is cooled to room temperature; Step 4, the dissolved binder and plasticizer in step 3 are added to the completed ball mill tank in step 2, and ball milling is carried out again for 12 hours. The proportion of Fe-Si-Cr powder, binder and plasticizer is 100:3:2.

[0013] Step 5, the slurry completed in step 4 is filtered through a 400 mesh filter screen, and vacuum defoaming is carried out; Step 6, the slurry in step 5 is tape cast on a casting machine, the casting temperature is 80℃, the casting knife edge is controlled at 30um, and the casting belt speed is 1.0m / min; Step 7, the film in step 6 is laminated, the lamination pressure is 80T, and the lamination temperature is 70℃. The laminated block is cut into magnetic rings, and hydrogen degassing is carried out at 400℃ for 2 hours, and hydrogen sintering is carried out at 800℃ for 30-60min to obtain a metal powder matrix.

[0014] The Fe-Si-Cr metal slurry obtained in example 1 has a solid content of 93.9%, the appearance of the tape casting film is free of scratches and holes, and the density is 4.7g / cm 3 , and the magnetic permeability of the sintered magnetic ring is 48.1 (1MHz); Example 2 A Fe-Si-Cr metal powder tape casting film preparation method comprises: Step 1, Fe-Si-Cr powder, dispersant, organosiloxane polymer, solvent are prepared according to 100:0.5:1:40 (mass ratio); Step 2, the prepared ingredients in step 1 are loaded into a ball mill tank, zirconia balls are used as grinding medium, and the powder: zirconia ball is 1:2 (mass ratio) for ball milling for 12 hours, and the ball mill speed is 60 rpm; Step 3, the binder and plasticizer are added to the solvent in a ratio of 1:2 for water bath stirring and dissolution, the water bath temperature is 70℃, and after complete dissolution, it is cooled to room temperature; Step 4, the binder and plasticizer after step 3 are added to the ball mill tank after step 2, and ball milling is performed again for 12 hours. The ratio of Fe-Si-Cr powder, binder and plasticizer is 100:5:2.

[0015] Step 5, the slurry after step 4 is filtered through a 400 mesh filter screen, and vacuum defoaming is performed; Step 6, the slurry in step 5 is cast on a casting machine, the casting temperature is 80℃, the casting knife edge is controlled at 33um, and the casting belt speed is 1.0m / min; Step 7, the film in step 6 is laminated, the lamination pressure is 80T, and the lamination temperature is 70℃. The laminated bar is cut into magnetic rings, and degassing is performed at 400℃ for 2 hours, and sintering is performed at 800℃ for 30-60min to obtain a metal powder matrix.

[0016] Example 2, compared with example 1, the powder type is unchanged, the dispersant ratio is increased to 1%, and the binder is increased to 5%, the obtained Fe-Si-Cr metal slurry solid content is 91.7%, and the density is 4.9g / cm 3 , the magnetic permeability of the magnetic ring after sintering is 50.2(1MHz); as shown in Figure 1 , the appearance of the cast film is free of scratches and holes, and the micro powder distribution is uniform and dense.

[0017] Example 3 A Fe-Si-Al metal powder casting film preparation method comprises: Step 1, Fe-Si-Al powder, dispersant, organosiloxane polymer and solvent are prepared according to a mass ratio of 100:1:1:40; Step 2, the prepared ingredients in step 1 are loaded into a ball mill tank, zirconium balls are used as grinding media, and ball milling is performed for 12 hours according to a mass ratio of powder: zirconium ball = 1:2, the speed of the ball mill is 60rpm; Step 3, the binder and plasticizer are added to the solvent according to a ratio of 1:2, and water bath stirring is performed for dissolution, the water bath temperature is 70℃, and after complete dissolution, cooling is performed to room temperature; Step 4, the binder and plasticizer after step 3 are added to the ball mill tank after step 2, and ball milling is performed again for 12 hours. The ratio of Fe-Si-Al powder, binder and plasticizer is 100:5:2.

[0018] Step 5, the slurry after step 4 is filtered through a 400 mesh filter screen, and vacuum defoaming is performed; Step 6, the slurry in step 5 is cast on a casting machine, the casting temperature is 80℃, the casting knife edge is controlled at 32um, and the casting belt speed is 1.0m / min; Step 7, the film in step 6 is laminated, laminating pressure 80T, laminating temperature 70℃. The laminated bar is cut into magnetic rings, and the hydrogen is discharged at 400℃ for 2 hours, and the hydrogen is sintered at 800℃ for 30-60min to obtain a metal powder matrix.

[0019] Example 3, compared with example 2, the powder type is changed to Fe-Si-Al, and the proportion of other organic matters is unchanged. The obtained Fe-Si-Al metal slurry has a solid content of 91.7%, and the cast film has no scratches and no holes, and the density is 4.6g / cm 3 , and the magnetic permeability of the magnetic ring after sintering is 46.8 (1MHz).

Claims

1. A method of preparing a metal powder tape casting slurry, characterized by, The preparation method comprises the following steps: Step 1, the Fe-Si system powder, dispersant, organosiloxane polymer, solvent are prepared according to the mass ratio of 100:0.5-3:1:40; Step 2, the prepared ingredients in step 1 are loaded into a ball mill tank, and the powder:zirconium ball is 1:2, and the ball mill is 10-12 hours, and the rotation speed of the ball mill is 50-70 rpm; Step 3, the binder and plasticizer are added to the solvent according to the ratio of 1:2-4, and the water bath stirring is dissolved, the water bath temperature is 50-80 DEG C, and the solution is cooled to room temperature after complete dissolution; Step 4, the binder and plasticizer dissolved in step 3 are added to the ball mill tank completed in step 2, and ball milling is carried out again for 12 hours; wherein the Fe-Si system powder, binder and plasticizer are 100:3-8:2; Step 5, the slurry completed in step 4 is filtered, and vacuum defoaming is carried out, to obtain the casting slurry.

2. A method of preparing a metal powder tape casting slurry as claimed in claim 1, wherein, The Fe-Si system metal powder in step 1 is Fe-Si-Al and / or Fe-Si-Cr, the dispersant is AD-3172M, and the organosiloxane polymer is DOWSILTMOP-8550; The solvent in step 1 and step 3 is anhydrous ethanol and acetone respectively; The binder in step 3 is polyvinyl butyral with a molecular weight of 170000-250000, and the plasticizer is dioctyl phthalate.

3. A metal powder tape casting slurry characterized by, The casting slurry is prepared by the preparation method of claim 1 or 2.

4. Use of a metal powder tape casting slurry according to claim 3, characterized in that, The casting slurry is used for making metal powder matrix: Step 6, the slurry in step 5 in claim 1 is cast on a casting machine, the casting temperature is 50-80 DEG C, the casting knife edge is controlled at 20um-100um, and the casting belt speed is 0.5-1.5 m / min; Step 7, the film in step 6 is laminated, the laminating pressure is 80T, the laminating temperature is 65-75 DEG C, the cut bar block is cut after lamination, and the hydrogen degassing is carried out at 390-410 DEG C for 2 hours, and the hydrogen sintering is carried out at 790-810 DEG C for 30-60 min, to obtain the metal powder matrix.

Images