Percolating Filter With PdNi Gradient Coating for Corrosion Resistance

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Solution Overview

Problem

Filtration filters used for trapping biological materials face issues with corrosion resistance due to defects in the noble metal coating, leading to exposure of the non-precious metal base material to electrolyte solutions, resulting in localized corrosion.

Innovation Solution

A filtration filter design featuring a surface layer composed mainly of Pd, a base material composed mainly of a PdNi alloy, and an intermediate layer composed mainly of a PdNi alloy with varying Pd:Ni ratios, which disperses the interface and reduces corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a surface layer of noble metal is plated on a non-precious metal base material, then the corrosion resistance is improved, but defects in the coating expose the base material to electrolyte solutions causing localized corrosion

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidlocalized corrosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An intermediate layer composed of PdNi alloy is introduced between the noble metal surface layer and the non-precious metal base material. This intermediate layer acts as a mediator that disperses the interface between dissimilar metals, preventing direct contact and reducing galvanic corrosion when coating defects are present.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The filtration filter employs a composite structure with three distinct layers: a noble metal surface layer, a PdNi alloy intermediate layer with specific composition ratios, and a non-precious metal base material. This composite structure combines the advantages of each material while mitigating their individual weaknesses through proper interface design.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If a simple two-layer structure (noble metal coating on non-precious metal base) is used, then the manufacturing process is simple, but the corrosion resistance is insufficient due to direct metal-metals interface exposure

Engineering Contradiction:
Improvecoating process simplicityVSAvoidcorrosion resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The coating structure is segmented into three functional layers instead of a simple two-layer structure. The intermediate PdNi alloy layer is specifically designed to disperse the interface between the noble metal and non-precious metal, creating a more robust corrosion-resistant system while maintaining manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

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 design significantly enhances corrosion resistance by preventing direct contact between the noble metal and non-precious metal, thereby reducing corrosion and improving the durability of the filtration process.

Implementation Method 1

defects in the noble metal coating, leading to exposure of the non-precious metal base material to electrolyte solutions, resulting in localized corrosion

Methodology Applied
Scientific EffectGalvanic corrosion:

Data Source

PatentEP3845288B1Percolating filter
Publication Date: 2025.10.29 MURATA MFG CO LTD
  • EP3845288B1 patent drawingFigure 1~2
  • EP3845288B1 patent drawingFigure 3~4D
  • EP3845288B1 patent drawingFigure 4E~5

AI summary

A filtration filter according to the present invention includes a surface layer, a base material formed inside the surface layer, and an intermediate layer formed between the surface layer and the base material, wherein the surface layer is composed mainly of Pd, the base material is composed mainly of a PdNi alloy, and the intermediate layer is composed mainly of a PdNi alloy in which a Pd:Ni ratio changes from a surface layer side toward a base material side. A filtration filter with such a structure can have improved corrosion resistance.