Metal-Plated Stainless Steel Surface Modification

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Solution Overview

Problem

Metal-plated stainless materials face issues with nonuniform metal plating layer thickness, leading to reduced corrosion resistance, electrical conductivity, and smoothness due to variations in the oxide film thickness on stainless steel surfaces, which affects interfacial adhesion and coverage.

Innovation Solution

A method involving acid treatment and etching steps to uniformly modify the oxide film on stainless steel surfaces, followed by a metal plating process, ensuring a thin and uniform metal plating layer is formed, regardless of initial oxide film thickness variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the metal plating layer thickness is reduced to lower cost, then cost decreases, but coverage and corrosion resistance deteriorate

Engineering Contradiction:
Improvemetal plating layer thicknessVSAvoidcorrosion resistance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies preliminary oxide film formation treatment before metal plating to create a uniform base layer. This preliminary action ensures that even when metal plating thickness is reduced, the plating layer maintains uniform coverage and adhesion, preventing corrosion resistance deterioration. The oxide film acts as a preparatory foundation that enables thin plating to achieve adequate protection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the surface parameters of the stainless steel substrate by controlling oxide film thickness and composition through oxidation treatment. By adjusting oxidation conditions (time, temperature, atmosphere), the surface properties are optimized to enhance metal plating adhesion and coverage, allowing reduced plating thickness while maintaining corrosion resistance.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If metal plating is performed directly on stainless steel without underlying nickel plating, then process complexity and cost decrease, but interfacial adhesion property deteriorates

Engineering Contradiction:
Improveplating process complexityVSAvoidinterfacial adhesion property
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent extracts and removes the underlying nickel plating layer from the conventional structure, eliminating this intermediate layer entirely. Instead, it directly forms an oxide film on the stainless steel surface through oxidation treatment, which serves as the bonding interface for the metal plating layer, thereby simplifying the process while maintaining adhesion.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the surface chemistry of the stainless steel by creating a controlled oxide film with specific composition and thickness. This parameter change in surface properties (oxidation state, surface energy) enables direct metal plating to achieve adequate interfacial adhesion without requiring nickel plating, thus reducing process complexity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If cathodic electrolysis treatment is used to form oxide film, then anticorrosion property improves, but uniformity of oxide film thickness deteriorates due to complex shape or high electrical resistance

Engineering Contradiction:
Improveanticorrosion propertyVSAvoidoxide film thickness uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the cathodic electrolysis method (electrical field-based) with direct oxidation treatment (chemical/thermal field-based). This substitution eliminates the dependency on electrical conductivity and current distribution, allowing uniform oxide film formation on complex-shaped or high-resistance stainless steel components without the nonuniformity problems inherent in electrolytic methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the treatment methodology from electrochemical to thermochemical oxidation. By controlling temperature, oxygen partial pressure, and treatment time, uniform oxide films are formed regardless of component geometry or electrical properties, achieving both anticorrosion protection and thickness uniformity that electrolysis cannot provide for complex shapes.

Inventive Principle:
Principle #35Parameter changes

4Stability of the object's composition

If oxide film thickness varies on stainless steel surface, then natural oxidation occurs, but metal plating uniformity and coverage deteriorate

Engineering Contradiction:
Improveoxide film formationVSAvoidmetal plating layer uniformity
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies a preliminary controlled oxidation treatment to standardize the oxide film thickness and composition before metal plating. This preliminary action eliminates the natural variation in oxide film that occurs during storage or handling, creating a uniform baseline surface that ensures consistent metal plating deposition and coverage across all parts.

Inventive Principle:
Principle #10Preliminary action

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 method achieves improved interfacial adhesion, corrosion resistance, and electrical conductivity by ensuring a uniform metal plating layer, effectively addressing the issues of nonuniformity and enhancing the properties of metal-plated stainless materials for applications like connectors and fuel cell separators.

Implementation Method 1

a film growth step of growing the oxide film (11) using an oxidation treatment agent

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

an etching step of treating the stainless steel material after the acid treatment step with an etching treatment agent

Methodology Applied
Scientific EffectEtching:

Data Source

PatentEP3231893B1Method for producing metal-plated stainless steel material
Publication Date: 2021.03.31 TOYO KOHAN CO LTD
  • EP3231893B1 patent drawingFigure 1
  • EP3231893B1 patent drawingFigure 2
  • EP3231893B1 patent drawingFigure 3

AI summary

There is provided a method for producing a metal-plated stainless material (1), the method comprising: performing an acid treatment of treating a stainless steel material (10) with an acidic solution; performing an etching of treating the stainless steel material (10) after the acid treatment with an etching treatment agent; and a modifying the surface of the stainless steel material (10) after the etching into a state suitable for a metal plating process.