Ti-Zr-X Alloy Capacitor Element Suppressing Leakage Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid electrolytic capacitors using titanium as the valve action metal face issues with high leakage current, while those using Ti-Zr alloys achieve low leakage current but at the cost of reduced relative permittivity, limiting their electrostatic capacitance.
Innovation Solution
A solid electrolytic capacitor element is developed with a porous body made from a sintered Ti-alloy-containing grain having a Ti-Zr-X multicomponent alloy on its surface, where X is selected from Si, Hf, Y, Al, Mo, W, Ta, Nb, and V, optimizing the composition to balance high electrostatic capacitance with suppressed leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If titanium is used as the valve action metal to increase relative permittivity, then electrostatic capacitance is improved, but leakage current becomes large
Solution Approach 1:
The invention uses a composite alloy structure consisting of a Ti-Zr base alloy with surface-coated third elements (Ta, Nb, W, Mo, or Hf). This composite material approach combines the high relative permittivity of titanium-based materials with the low leakage current characteristics of refractory metal coatings, resolving the contradiction between capacitance and leakage current
Solution Approach 2:
The invention applies different material properties to different locations: the bulk Ti-Zr alloy provides high relative permittivity for capacitance, while the surface coating of refractory metals (Ta, Nb, W, Mo, or Hf) provides low leakage current characteristics. This local differentiation of material quality allows simultaneous optimization of both parameters
2Object-generated harmful factors
If Ti-Zr alloy is used to reduce leakage current, then leakage current is suppressed, but relative permittivity decreases greatly
Solution Approach 1:
The invention creates a composite alloy system where Ti and Zr form the base providing low leakage current, while surface-coated refractory metals (Ta, Nb, W, Mo, or Hf) contribute high relative permittivity. This composite structure reverses the traditional approach by placing the high-permittivity material as a surface layer rather than the bulk material
3Ease of manufacture
If aluminum is used as the valve action metal to maintain low cost and good capacitance, then manufacturing ease is improved, but leakage current becomes larger compared to Ti-Zr alloys
Solution Approach 1:
The invention changes the compositional parameters of the alloy system by introducing specific ratios of Ti (5-40 mass%), Zr (5-40 mass%), and refractory metal elements (Ta, Nb, W, Mo, or Hf at 1-20 mass%). This parameter optimization allows achieving low leakage current characteristics similar to Ti-Zr alloys while maintaining manufacturing feasibility and cost-effectiveness
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 enables a solid electrolytic capacitor with enhanced electrostatic capacitance while maintaining low leakage current, achieving stable operation with improved relative permittivity and reduced internal resistance.
Implementation Method 1
forming a dielectric oxide film layer by chemical conversion treatment on the surface of an electrode body made from a valve action metal and having been subjected to surface roughing treatment by etching
Implementation Method 2
a porous body made from a sintered body of Ti-alloy-containing grains
Implementation Method 3
forming a solid electrolyte layer made from a conductive polymer on the cathode portion
Data Source
AI summary
A solid electrolytic capacitor element that includes a porous body, a dielectric layer on a surface of the porous body, and a solid electrolyte layer on a surface of the dielectric layer. The porous body is made from a sintered body of a Ti-alloy-containing grain having a Ti—Zr—X multicomponent alloy on a surface thereof, where X is at least one valve metal element selected from Si, Hf, Y, Al, Mo, W, Ta, Nb, and V, and a composition of the Ti—Zr—X multicomponent alloy is Ti: 50 atm % to 80 atm %, Zr: 8 atm % to 32 atm %, and X: 1 atm % to 20 atm %.