Sliding Member Clear Topcoat for Glossy Corrosion Resistance

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Solution Overview

Problem

Zinc alloy-plated films used for high-design sliding members are costly and lack versatility, as they require specialized production lines and can't be manufactured with conventional zinc-plating processes, while they also suffer from interference colors that affect glossiness.

Innovation Solution

A sliding member with a surface-treated layer comprising a zinc-plated layer, a chemical conversion-treated layer with chromium and oxygen, and a clear topcoat layer made from materials like silica compounds or resins, which enhances glossiness, reduces interference colors, and improves corrosion resistance without modifying conventional zinc-plating production lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical conversion treatment is applied to zinc plating to prevent white rust, then corrosion resistance is improved, but interference colors appear on the surface causing color irregularity

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidsurface color uniformity

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

A clear topcoat layer is applied as an intermediary over the chemical conversion-treated zinc-plated surface. This topcoat layer masks the interference colors and color irregularities produced by the chemical conversion treatment, while allowing the underlying corrosion protection to remain effective. The topcoat acts as a visual barrier that eliminates the unwanted appearance effects without compromising the corrosion resistance function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Shape

If nickel-containing zinc alloy plating is used to achieve high-design appearance, then glossiness and design quality are improved, but manufacturing cost increases and production line complexity increases

Engineering Contradiction:

ImproveglossinessVSAvoidmanufacturing cost

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

Instead of using expensive nickel-containing zinc alloy plating, the invention employs a simple clear topcoat layer applied over conventional zinc plating. This clear coating provides the necessary glossiness and high-design appearance at minimal cost, replacing the need for costly alloy formulations. The clear topcoat is a cost-effective solution that achieves the desired aesthetic without the high material costs of nickel-based alloys.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention creates a composite structure consisting of a zinc-plated layer combined with a clear topcoat layer. This composite system achieves the glossiness and design quality previously obtainable only through expensive nickel-containing alloys. The combination of conventional zinc plating with a clear protective coating produces a cost-effective alternative that maintains aesthetic requirements while eliminating the need for specialized alloy compositions.

Inventive Principle:

Principle #40Composite materials

3Shape

If nickel-containing zinc alloy plating is used for high-design appearance, then glossiness is improved, but the production line must be specially modified reducing versatility

Engineering Contradiction:

ImproveglossinessVSAvoidproduction line versatility

Core Design Contradiction:

ShapeVSAdaptability or versatility

Solution Approach 1:

The clear topcoat layer serves multiple functions: it provides glossiness for high-design appearance, protects the underlying zinc plating, and can be applied using conventional coating equipment. This single clear coating step can be integrated into existing zinc-plating production lines without requiring specialized alloy plating equipment, making the process universally applicable to standard production facilities while achieving the desired aesthetic results.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 a high-gloss, cost-effective sliding member with improved corrosion resistance and sliding performance, maintaining a silver-colored appearance while avoiding interference colors, and can be manufactured using standard zinc-plating equipment.

Implementation Method 1

chemical conversion treatment using chromic acid to prevent white rust described above, and prevents both a cause of white rust and dissolution of zinc due to the synergistic effects of the zinc plating and the chemical conversion-treated layer

Methodology Applied

Scientific EffectChemical conversion treatment:

Implementation Method 2

Zinc dissolves itself so as to prevent corrosion of the metal substrate

Methodology Applied

Scientific EffectSacrificial corrosion:

Data Source

PatentUS11788191B2High-design sliding member

Publication Date: 2023.10.17 NISSAN MOTOR CO LTD

AI summary

A sliding member includes, on a surface of a metal substrate, a surface-treated layer including a zinc-electroplated layer, a chemical conversion-treated layer, and a topcoat layer sequentially stacked on the metal substrate. The chemical conversion-treated layer includes chromium and oxygen. The topcoat layer includes at least one material selected from the group consisting of a silica compound, acrylic resin, polyurethane resin, epoxy resin, phenol resin, and melamine resin. A method of manufacturing the sliding member includes a step of forming, on a surface of the chemical conversion-treated layer, the topcoat layer including at least one material selected from the group consisting of a silica compound, acrylic resin, polyurethane resin, epoxy resin, phenol resin, and melamine resin.