Casting slurry for metal soft magnetic powder-based laminated chip inductor and preparation method of casting slurry

Abstract

The invention discloses tape casting slurry for a metal soft magnetic powder-based laminated chip inductor and a preparation method of the tape casting slurry, and belongs to the field of passive electronic components. Magnetic powder is dispersed in a ball milling mode, a layer of dispersing agent is uniformly bonded on the surface of the magnetic powder in a chemical or physical mode, the dispersity of the magnetic powder in a solution system is further improved, and the flowability of tape casting slurry and the strength of a film after tape casting are adjusted by adjusting the types and proportions of adhesives and auxiliaries; the preparation method has the beneficial effects that 1, the dispersity of the magnetic powder in a solution system is further improved; and 2, the flowability of the tape casting slurry and the strength of the film after tape casting are improved, and the risk of damage of the film in punching printing and tabletting can be reduced.

Description

Technical Field

[0001] This invention relates to a casting paste and its preparation method for a metal soft magnetic powder-based multilayer chip inductor, belonging to the field of casting pastes and passive electronic components. Background Technology

[0002] With the rapid development of the integrated circuit industry, miniaturization and thinning of electronic products have become inevitable trends. Inductors, as a type of passive electronic component, are evolving towards chip-type, composite, multifunctional, and high-frequency designs. Currently, micro-inductors manufactured using monolithic molding methods suffer from difficulties in coil winding and low inductance accuracy. Tape casting technology is the mainstream technology for manufacturing chip components. Chip component production involves processes such as paste preparation, tape casting, screen printing of internal electrodes, lamination, sintering, firing of terminal electrodes, and performance testing. The characteristics of currently used soft magnetic powders differ significantly from ceramic and ferrite powders, meaning their paste formulation schemes may not be universally applicable. Therefore, how to formulate a metal soft magnetic powder-based tape casting paste is the main challenge in manufacturing metal soft magnetic powder-based multilayer chip inductors via tape casting. Summary of the Invention

[0003] This invention disperses magnetic powder by ball milling and uniformly bonds a layer of dispersant to the surface of the magnetic powder by chemical or physical means, thereby further improving the dispersibility of the magnetic powder in the solution system. By adjusting the type and ratio of binder and additives, the fluidity of the casting slurry and the strength of the film after casting can be adjusted. Specifically, it includes the following steps: S1. Add magnetic powder and grinding balls to a ball mill jar for later use. The magnetic powder particle size is 0.5μm~50μm, and the grinding balls account for 50wt.%~500wt.% of the magnetic powder by mass. The magnetic powder is any one or a combination of two or more of FeSiCr, FeSiAl, FeNi, and FeSi magnetic powders.

[0004] S2. Add the dispersant to organic solvent 1, heat and stir until a clear and transparent solution is obtained, to obtain mixed solvent 1, and add mixed solvent 1 to the magnetic powder in step S1 to obtain mixed component 1; wherein the dispersant accounts for 0.05wt.% to 5wt.% of the magnetic powder by mass, the organic solvent 1 accounts for 5wt.% to 15wt.% of the magnetic powder by mass, the stirring temperature is 25℃ to 80℃, and the stirring time is 0.5 to 10h; The organic solvent 1 is any one or a combination of two or more of the following: ethanol, propanol, acetone, butanone, pentanone, ethylene glycol butyl ether, ethyl lactate, ethylene glycol methyl ether, cyclohexanone, butyl acetate, n-propyl acetate, methyl isobutyl methanol, etc. The dispersant is any one or a combination of two or more of the following: hexadecyltrimethylammonium bromide, polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, silane coupling agent, sodium oleate, tetradecyl alcohol, etc. S3. Disperse the mixture 1 by ball milling using a ball mill, wherein the ball mill speed is 100~300 rpm and the ball milling time is 1~5h; S4. Add the binder and additives to organic solvent 2, heat and stir until a clear and transparent solution is obtained to obtain mixed solvent 2; wherein the binder accounts for 1 wt.% to 10 wt.% of the magnetic powder by mass, the additives account for 1 wt.% to 10 wt.% of the magnetic powder by mass, the organic solvent 2 accounts for 5 wt.% to 15 wt.% of the magnetic powder by mass, the stirring temperature is 25 to 80 ℃, and the stirring time is 0.5 to 10 h; The adhesive is any one or a combination of two or more of the following: thermoplastic resins (polyvinyl butyral, acrylic resin, acrylic maleic acid copolymer, poly(methyl methacrylate), polystyrene butadiene copolymer), thermosetting resins (bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin). adhesive The additives are any one or a combination of two or more of the following: glyceryl triacetate, diethyl adipate, polyethylene glycol, tributyl phosphate, triethylene glycol diacetate, dibutyl sebacate, diisopropyl adipate, butyl benzyl phthalate, diallyl phthalate, dicyclohexyl phthalate, diethyl phthalate, diisobutyl phthalate, tricresyl phosphate, and bis(2-ethylhexyl) adipate. Additives S5. Add mixed solvent 2 to mixed component 1 to obtain mixed component 2, and disperse it by ball milling using a ball mill, wherein the ball mill speed is 100~300 rpm and the ball milling time is 1 h~5 h; S6. Use a filter screen to filter out the grinding balls in the mixed component 2 to obtain a casting slurry for metal soft magnetic powder-based multilayer chip inductors, wherein the mesh size of the filter screen is 60~300 mesh; The filter screen is made of PP filter screen, stainless steel filter screen, copper filter screen, etc. The beneficial effects of this invention patent are as follows: 1. Magnetic powder is dispersed by ball milling, and a dispersant layer is uniformly bonded to the surface of the magnetic powder by chemical or physical means to further improve the dispersibility of the magnetic powder in the solution system; 2. This method can adjust the type and ratio of binders and additives, improve the fluidity of the casting paste and the strength of the film after casting, and reduce the risk of film breakage during punching, printing and pressing. Detailed Implementation

[0005] The present invention will be described in detail with reference to the embodiments.

[0006] Example 1 FeSiCr magnetic powder and grinding balls were added to a ball mill jar for later use. The magnetic powder had a particle size of 5 μm, and the mass ratio of grinding balls to magnetic powder was 300 wt.%. 1 wt.% of coupling agent dispersant was added to 10 wt.% organic solvent 1 (butyl acetate), and the mixture was heated and stirred until a clear and transparent solution was obtained (stirring temperature: 25 ℃, stirring time: 0.5 h) to obtain mixed solvent 1. Mixed solvent 1 was then added to the magnetic powder to obtain mixed component 1. Mixed component 1 was dispersed by ball milling at 100 rpm for 4 h. 3 wt.% thermoplastic resin binder and 1.5 wt.% additive (glyceryl triacetate) were added to 10 wt.% organic solvent 2 (butyl acetate), and the mixture was heated and stirred until a clear and transparent solution was obtained (stirring temperature: 50 ℃, stirring time: 10 h) to obtain mixed component 1. h), to obtain mixed solvent 2; add mixed solvent 2 to mixed component 1 to obtain mixed component 2, and disperse it by ball milling using a ball mill, wherein the ball mill speed is 100 rpm and the ball milling time is 4 h; filter out the grinding balls in mixed component 2 using a filter screen to obtain a casting slurry for metal soft magnetic powder based multilayer chip inductor, wherein the filter screen mesh number is 60 mesh.

[0007] Example 2 FeSiCr magnetic powder and grinding balls were added to a ball mill jar for later use. The magnetic powder had a particle size of 5 μm, and the mass ratio of grinding balls to magnetic powder was 300 wt.%. 1 wt.% of coupling agent dispersant was added to 10 wt.% organic solvent 1 (butyl acetate), and the mixture was heated and stirred until a clear and transparent solution was obtained (stirring temperature: 25 ℃, stirring time: 0.5 h) to obtain mixed solvent 1. Mixed solvent 1 was then added to the magnetic powder to obtain mixed component 1. Mixed component 1 was dispersed by ball milling at 100 rpm for 8 h. 5 wt.% thermoplastic resin binder and 1 wt.% additive (glyceryl triacetate) were added to 10 wt.% organic solvent 2 (butyl acetate), and the mixture was heated and stirred until a clear and transparent solution was obtained (stirring temperature: 80 ℃, stirring time: 10 h) to obtain mixed component 1. h), to obtain mixed solvent 2; add mixed solvent 2 to mixed component 1 to obtain mixed component 2, and disperse it by ball milling using a ball mill, wherein the ball mill speed is 100 rpm and the ball milling time is 8 h; filter out the grinding balls in mixed component 2 using a filter screen to obtain a casting slurry for metal soft magnetic powder based multilayer chip inductor, wherein the filter screen mesh number is 60 mesh.

[0008] Example 3 FeSiCr magnetic powder and grinding balls were added to a ball mill jar for later use. The magnetic powder had a particle size of 5 μm, and the mass ratio of grinding balls to magnetic powder was 300 wt.%. 0.1 wt.% of a coupling agent-type dispersant was added to 10 wt.% of organic solvent 1 (butyl acetate), and the mixture was heated and stirred until a clear and transparent solution was obtained (stirring temperature: 25 ℃, stirring time: 0.5 h), resulting in mixed solvent 1. Mixed solvent 1 was then added to the magnetic powder to obtain mixed component 1. Mixed component 1 was dispersed by ball milling at 120 rpm for 10 h. 2 wt.% of a thermoplastic resin-type binder and 1 wt.% of an additive (glyceryl triacetate) were added to 10 wt.% of organic solvent 2 (butyl acetate), and the mixture was heated and stirred until a clear and transparent solution was obtained (stirring temperature: 70 ℃, stirring time: 10 h). h), to obtain mixed solvent 2; add mixed solvent 2 to mixed component 1 to obtain mixed component 2, and disperse it by ball milling using a ball mill, wherein the ball mill speed is 120 rpm and the ball milling time is 10 h; filter out the grinding balls in mixed component 2 using a filter screen to obtain a casting slurry for metal soft magnetic powder based multilayer chip inductor, wherein the filter screen mesh number is 60 mesh.

[0009] Table 1. Comparison of slurry flowability, membrane strength, and stack height reduction rate in the examples. Example 1 Example 2 Example 3 Liquidity(s) 60 139 68 Density (g / cm3) 4.78 4.38 4.75 Diaphragm strength (MPa) 154 217 102 Diaphragm height reduction rate during stacking (%) -12.33% -11.73% -14.14%

Claims

1. A method for preparing a casting paste for multilayer chip inductors based on metal soft magnetic powder, characterized in that, The preparation method includes the following steps: S1. Add magnetic powder and grinding balls to a ball mill jar for later use. The magnetic powder particle size is 0.5μm~50μm, and the grinding balls account for 50wt.%~500wt.% of the magnetic powder by mass. S2. Add the dispersant to organic solvent 1, heat and stir until a clear and transparent solution is obtained, to obtain mixed solvent 1, and add mixed solvent 1 to the magnetic powder in step S1 to obtain mixed component 1; the mass ratio of dispersant to magnetic powder is 0.05wt.% to 5wt.%, the mass ratio of organic solvent 1 to magnetic powder is 5wt.% to 15wt.%, the stirring temperature is 25℃ to 80℃, and the stirring time is 0.5 to 10h; S3. Disperse the mixture 1 by ball milling using a ball mill, wherein the ball mill speed is 100~300 rpm and the ball milling time is 1~5h; S4. Add the binder and additives to organic solvent 2, heat and stir until a clear and transparent solution is obtained to obtain mixed solvent 2; wherein the binder accounts for 1 wt.% to 10 wt.% of the magnetic powder by mass, the additives account for 1 wt.% to 10 wt.% of the magnetic powder by mass, the organic solvent 2 accounts for 5 wt.% to 15 wt.% of the magnetic powder by mass, the stirring temperature is 25 to 80 ℃, and the stirring time is 0.5 to 10 h; S5. Add mixed solvent 2 to mixed component 1 to obtain mixed component 2, and disperse it by ball milling using a ball mill, wherein the ball mill speed is 100~300 rpm and the ball milling time is 1 h~5 h; S6. Use a filter screen to filter out the grinding balls in the mixed component 2 to obtain a casting slurry for metal soft magnetic powder-based multilayer chip inductors, wherein the filter screen mesh number is 60~300 mesh.

2. The method for preparing the casting paste for multilayer chip inductors based on metal soft magnetic powder as described in claim 1, characterized in that, The magnetic powder mentioned in step S1 is one or more of FeSiCr, FeSiAl, FeNi, and FeSi magnetic powder.

3. The method for preparing the casting paste for multilayer chip inductors based on metal soft magnetic powder as described in claim 1, characterized in that, In step S2, organic solvent 1 is one or more of ethanol, propanol, acetone, butanone, pentanone, ethylene glycol butyl ether, ethyl lactate, ethylene glycol methyl ether, cyclohexanone, butyl acetate, n-propyl acetate, and methyl isobutyl methanol.

4. The method for preparing the casting paste for multilayer chip inductors based on metal soft magnetic powder as described in claim 1, characterized in that, In step S2, the dispersant is one or more of the following: hexadecyltrimethylammonium bromide, polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, silane coupling agent, sodium oleate, and tetradecyl alcohol.

5. The method for preparing the casting paste for multilayer chip inductors based on metal soft magnetic powder as described in claim 1, characterized in that, In step S4, the adhesive is one or more of the following: polyvinyl butyral, acrylic resin, acrylic maleic acid copolymer, poly(methyl methacrylate), polystyrene butadiene copolymer, bisphenol A epoxy resin, bisphenol F epoxy resin, and phenolic epoxy resin.

6. The method for preparing the casting paste for multilayer chip inductors based on metal soft magnetic powder as described in claim 1, characterized in that, In step S4, the auxiliary agent is any one or more of the following: glyceryl triacetate, diethyl adipate, polyethylene glycol, tributyl phosphate, triethylene glycol diacetate, dibutyl sebacate, diisopropyl adipate, butyl benzyl phthalate, diallyl phthalate, dicyclohexyl phthalate, diethyl phthalate, diisobutyl phthalate, tricresyl phosphate, and bis(2-ethylhexyl) adipate.

7. The method for preparing the casting paste for multilayer chip inductors based on metal soft magnetic powder as described in claim 1, characterized in that, In step S6, the filter screen is a PP filter screen, a stainless steel filter screen, or a copper filter screen.

8. A casting paste for multilayer chip inductors based on soft magnetic powder, characterized in that, The casting slurry is prepared by the method described in any one of claims 1-7.

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