Laminated Inductor with Ti-Ni-Cu-Mn-Zr-Ag Dielectric Layer
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Solution Overview
Problem
Laminated power choke coils in DC/DC converters face issues with temperature characteristics variability, magnetic saturation, and delamination due to diffusion of components during sintering, leading to poor performance and stability.
Innovation Solution
A laminated inductor design featuring Ni—Zn—Cu ferrite magnetic layers and a Ti—Ni—Cu—Mn—Zr—Ag dielectric nonmagnetic layer, with Ag2O addition to promote inter-diffusion and reduce stress, forming a bonded interface and preventing delamination, while maintaining favorable DC superimposition characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nonmagnetic layer made of Zn—Cu ferrite is used to suppress magnetic saturation, then superimposition characteristics are improved, but component diffusion occurs during sintering causing Ni concentration slope and poor temperature characteristics
Solution Approach 1:
The invention changes the material composition parameters by replacing Zn—Cu ferrite with TiO2-based dielectric ceramic containing specific amounts of NiO, CuO, Mn3O4, and other oxides. This compositional change eliminates component diffusion during sintering while maintaining the nonmagnetic properties needed for suppressing magnetic saturation, thereby resolving the contradiction between improved superimposition characteristics and stable temperature characteristics.
Solution Approach 2:
The invention uses a composite dielectric ceramic material comprising TiO2 as the base with multiple metal oxides (NiO, CuO, Mn3O4, etc.) added in specific proportions. This composite structure provides both the nonmagnetic properties for magnetic saturation suppression and compositional stability during sintering, preventing the Ni concentration slope issue while maintaining reliable superimposition characteristics.
2Reliability
If nonmagnetic layers with low affinity to magnetic material layers are used, then magnetic saturation is suppressed, but delamination occurs easily due to latent stress relief
Solution Approach 1:
The invention modifies the chemical composition parameters of the nonmagnetic layer by incorporating metal oxides such as NiO, CuO, and Mn3O4 in specific proportions. These compositional changes create favorable chemical affinity between the nonmagnetic layer and magnetic material layers, enabling strong bonding that prevents delamination while maintaining the ability to suppress magnetic saturation.
3Reliability
If glass materials are used as nonmagnetic materials, then magnetic saturation is suppressed, but delamination occurs at the bonded interface due to different coefficients of linear expansion
Solution Approach 1:
The invention replaces glass materials with a composite dielectric ceramic system based on TiO2 combined with metal oxides. This composite ceramic material has a coefficient of linear expansion that can be matched to ferrite magnetic materials, eliminating the dimensional mismatch problem that causes delamination, while maintaining the nonmagnetic properties for magnetic saturation suppression.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides stable temperature characteristics, suppresses delamination, and enhances production stability, ensuring favorable DC superimposition characteristics and inductance retention across temperature ranges.
Implementation Method 1
Ag2O addition to promote inter-diffusion and reduce stress, forming a bonded interface and preventing delamination
Implementation Method 2
simultaneous sintering with a magnetic layer
Implementation Method 3
form a nonmagnetic layer in a location where magnetic fluxes are concentrated, by means of simultaneous sintering with a magnetic layer, to suppress magnetic saturation and thereby improve superimposition characteristics
Data Source
AI summary
Disclosed is a laminated inductor that has good direct current superimposition characteristics, does not cause a variation in temperature characteristics, suppresses the occurrence of delamination, and can be stably manufactured. Also disclosed are a method for manufacturing the laminated inductor and a laminated choke coil. A laminated inductor (10) for use as a choke coil in a power supply circuit includes a rectangular parallelepiped-shaped laminated chip (1) and at least one pair of external electrodes (8) that are provided at the end of the laminated chip (1) and are conductively connected to the end of a coil. The laminated chip (1) includes a plurality of magnetic material layers (3) formed of an Ni—Zn—Cu ferrite, a plurality of conductive layers (2), which are laminated through the magnetic material layers (3) to constitute a coil, and at least one nonmagnetic layer (4) formed of a Ti—Ni—Cu—Mn—Zr—Ag-base dielectric material and formed in contact with a plurality of the magnetic material layers (3).