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, and belongs to the field of metal inductors and manufacturing thereof, and a Fe-Ni series metal diaphragm which is high in slurry solid content (larger than 90%), compact in tape casting diaphragm and free of holes is prepared by adjusting the proportion of an organosiloxane polymer, a dispersing agent and two kinds of polyvinyl butyral. The thickness of the Fe-Ni series metal diaphragm is adjustable in the range of 15-80 microns, the diaphragm density is 5.3 g / cm < 3 >, the magnetic conductivity after sintering exceeds 40 (1MHz), and the Fe-Ni series metal diaphragm can be suitable for preparing the diaphragm of the low-loss 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-Ni 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 material is 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 under large current for DC output rectifier filter choke, has good constant permeability characteristics, and the Curie temperature of metal powder is high, the permeability changes little in the working range, the reliability is high, and the Fe50-Ni50 alloy has low loss. 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 and other high computing power application scenarios.

[0003] However, with the further requirement of miniaturization, the common one-piece metal inductor is restricted by equipment, process and other conditions 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, the formula of metal powder casting slurry needs to be developed first, so as to 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 there is no related report on the Fe-Ni casting slurry formula. SUMMARY

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

[0005] The Fe-Ni 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 15-80um, the density of the film is 5.3g / cm 3 , and the permeability of the film after sintering is more than 40 (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-Ni system powder, dispersing agent, organosiloxane polymer and solvent are prepared according to 100:1-4:1.5:35 (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 the solution is cooled to room temperature after complete dissolution; Step 4, the dissolved binder and plasticizer 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 ratio of Fe-Ni system powder, binder and plasticizer is 100:2-5:1.8.

[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 60-70℃. The laminated block is cut into magnetic rings, and hydrogen degassing is carried out at 290-310℃ (preferably 300℃) for 2 hours, and hydrogen sintering is carried out at 720-760℃ (preferably 750℃) for 30min, to obtain a metal powder matrix.

[0008] Further, the Fe-Ni system metal powder in step 1 is Fe50-Ni50, the dispersant is AKM-0531, and the organosiloxane polymer is DOWSIL™ OP-8550; Further, the solvent in steps 1 and 3 is anhydrous ethanol and toluene, with a ratio of 62:38; Further, the binder in step 3 is two kinds of polyvinyl butyral, with a low molecular weight of 40000-70000 and a high molecular weight of 170000-250000 in a ratio of 3:2, and the plasticizer is dioctyl phthalate.

[0009] The present application has the advantages that the slurry prepared by the present application can be used to prepare a dense, non-film-removing, appearance-free scratch and hole, and thin film with consistent thickness, and ensure that it has a high density and magnetic permeability. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 The left photo is an optical microscope photo of the cast film of Example 1 at 20 times magnification, and the right photo is a scanning electron microscope micrograph at 3000 times magnification. DETAILED DESCRIPTION

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

[0012] Example 1 Step 1, the Fe-Ni powder, dispersant, organosiloxane polymer, solvent are prepared according to 100:2:1.5:35 (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 10-12 hours at a speed of 60 rpm; Step 3, the binder and plasticizer are added to the solvent according to a ratio of 1:2-4, and then stirred and dissolved in a water bath, the water bath temperature is 50-80℃, and after complete dissolution, it is cooled to room temperature; Step 4, the dissolved binder and plasticizer in 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-Ni powder, binder and plasticizer is 100:3:1.8.

[0013] Step 5, the slurry after step 4 is filtered through a 400 mesh filter and vacuum defoaming is performed; Step 6, the slurry in step 5 is cast on a casting machine, the casting temperature is 65℃, the casting knife edge is controlled at 50um, and the casting belt speed is 0.8m / min; Step 7, the film in step 6 is laminated, the lamination pressure is 80T, and the lamination temperature is 60℃. The laminated block is cut into a magnetic ring, and the metal powder matrix is obtained after degassing at 300℃ for 2 hours and sintering at 750℃ for 30 minutes.

[0014] The Fe-Ni metal slurry obtained in Example 1 has a solid content of 92.3%, the cast film has no scratches and no holes, the density is 5.3g / cm3, and the magnetic permeability of the sintered magnetic ring is 42.7 (1MHz); as shown in the figure, the cast film has no scratches and no holes, and the micro-powder is uniformly and densely distributed. Figure 1

[0015] Example 2 A Fe-Ni-Cr metal powder casting film preparation method comprises: Step 1, the Fe-Ni powder, dispersant, organosiloxane polymer, solvent are prepared according to 100:1:1.5:35 (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 10-12 hours at a speed of 60 rpm; ​Step 3, the binder and plasticizer are added into the solvent in a ratio of 1:2-4, and stirred and dissolved in a water bath, the water bath temperature is 50-80℃, and after complete dissolution, it is cooled to room temperature; Step 4, the dissolved binder and plasticizer in step 3 are added to the ball mill tank completed in step 2, and ball milling is carried out again for 12 hours. The ratio of Fe-Ni powder, binder and plasticizer is 100:5:1.8.

[0016] Step 5, the slurry completed in step 4 is filtered through a 400 mesh filter, and vacuum defoaming is carried out; Step 6, the slurry in step 5 is cast on a casting machine, the casting temperature is 65℃, the casting knife edge is controlled at 50um, and the casting belt speed is 0.8m / min; Step 7, the film in step 6 is laminated, the lamination pressure is 80T, and the lamination temperature is 60℃. The laminated block is cut into magnetic rings, and degassing is carried out at 300℃ for 2 hours, and sintering is carried out at 750℃ for 30min to obtain a metal powder matrix.

[0017] Compared with example 1, the dispersant ratio is reduced to 1%, and the binder is increased to 5%, the obtained Fe-Ni metal slurry solid content is 91.4%, the appearance of the cast film is free of scratches and holes, the density is 5.2g / cm3, and the magnetic permeability of the magnetic ring after sintering is 40.3(1MHz); In summary, by adjusting the ratio of organosiloxane polymer, dispersant and two kinds of polyvinyl butyral, a Fe-Ni metal film with high slurry solid content, dense cast film and no holes is prepared, and the magnetic permeability after sintering is more than 40. The preparation method is simple and easy to mass produce.

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-Ni system powder, dispersant, organosiloxane polymer, solvent are prepared according to the mass ratio of 100:1-4:1.5:35; Step 2, the prepared ingredients in step 1 are loaded into a ball mill tank, and zirconium balls are used as grinding media, and the ball milling is carried out for 10-12 hours at a mass ratio of powder: zirconium ball = 1:2, 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 and dissolution are carried out, the water bath temperature is 50-80 DEG C, and after complete dissolution, it is cooled to room temperature; Step 4, the binder and plasticizer dissolved in step 3 are added to the ball mill tank after step 2, and ball milling is carried out again; wherein the ratio of Fe-Ni system powder, binder and plasticizer is 100:2-5:1.8; Step 5, the slurry after step 4 is filtered through a 400 mesh filter screen, and vacuum defoaming is carried out, to obtain the metal powder casting slurry.

2. The preparation method of the metal powder casting slurry according to claim 2, characterized in that, In step 1, the Fe-Ni system metal powder is Fe50-Ni50, the dispersant is AKM-0531, and the organosiloxane polymer is DOWSIL OP-8550; In steps 1 and 3, the solvent is anhydrous ethanol and toluene, and the mass ratio is 62 ：38； In step 3, the binder is two kinds of polyvinyl butyral, with a low molecular weight of 40000-70000 and a high molecular weight of 170000-250000, and the mass ratio of the two is 3:2, and the plasticizer is dioctyl phthalate.

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

4. Use of a metal powder tape casting slurry according to claim 3, characterized in that, The metal powder casting slurry is used for preparing a metal diaphragm substrate: Step 6, the slurry in step 5 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 lamination pressure is 80T, the lamination temperature is 60-70 DEG C, the cut block after lamination is cut into a magnetic ring, and the hydrogen degassing is carried out at 290-310 DEG C, and the hydrogen sintering is carried out at 720-760 DEG C, to obtain the metal diaphragm substrate.

Images