Bi Overlay Electroplating Backing Steel Protection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The deposition of a Bi-based overlay layer on a plain bearing during electroplating leads to substitution and precipitation on the backing steel sheet, causing brittleness and surface roughening, which can result in fatigue destruction due to the electrochemical nobility of Bi ions and the resulting corrosion.

Innovation Solution

A protecting layer consisting of an electrochemically more noble metal, a base metal capable of forming a passivation state, or resin is formed on the back surface of the backing steel sheet to prevent Bi substitution and precipitation, ensuring the Bi-based overlay deposits only on the plain bearing alloy layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a Bi-based overlay layer is deposited by electroplating on a backing steel sheet, then the overlay layer can be successfully formed, but Bi ions substitute for Fe and precipitate on the back surface of the backing steel sheet causing corrosion and surface roughening

Engineering Contradiction:

Improveoverlay layer depositionVSAvoidcorrosion and surface roughening of backing steel sheet

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A protecting layer is introduced as an intermediary between the backing steel sheet and the Bi-based overlay layer. This protecting layer prevents direct contact and electrochemical interaction between Bi ions and the backing steel sheet, thereby eliminating the substitution and precipitation of Bi on the back surface while still allowing the overlay layer to be deposited on the plain bearing alloy layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The structure is segmented into distinct layers: the backing steel sheet, the protecting layer, the plain bearing alloy layer, and the Bi-based overlay layer. The protecting layer acts as a separate functional barrier that isolates the backing steel sheet from harmful electrochemical effects while maintaining the integrity of the overall structure.

Inventive Principle:

Principle #1Segmentation

2Productivity

If the backing steel sheet is immersed in plating liquor during electroplating, then the Bi-based overlay layer can be deposited, but the back surface of the backing steel sheet undergoes total corrosion and surface roughening

Engineering Contradiction:

Improveelectroplating processVSAvoiddurability of backing steel sheet

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The protecting layer is formed on the back surface of the backing steel sheet before the electroplating process. This preliminary protective measure ensures that when the backing steel sheet is immersed in the plating liquor, the back surface is already protected from corrosion and surface roughening, maintaining reliability throughout the production process.

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If Bi ions are used in the plating liquor instead of Pb ions, then environmental pollution is reduced, but Bi ions are electrochemically noble and cause substitution and precipitation on the backing steel sheet

Engineering Contradiction:

Improveenvironmental pollutionVSAvoidbrittleness and corrosion from Bi substitution

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The protecting layer serves as a mediator that allows the use of environmentally friendly Bi ions in the plating liquor while preventing the harmful effects of Bi substitution and precipitation on the backing steel sheet. This enables the adoption of Bi-based overlays without the detrimental side effects.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This method prevents corrosion and surface roughening of the backing steel sheet, thereby enhancing the durability and preventing fatigue failure during sliding contact.

Implementation Method 1

a Bi-based overlay layer is then deposited on the plain bearing alloy layer by electroplating

Methodology Applied

Scientific EffectElectroplating: Electroplating

Implementation Method 2

a base metal capable of forming a passivation state on a surface thereof

Methodology Applied

Scientific EffectPassivation:

Implementation Method 3

Bi ions in the plating liquor, which are electrochemically noble as compared to Fe, substitute for Fe of a backing steel sheet and precipitate on its back surface exposed in the plating liquor

Methodology Applied

Scientific EffectElectrochemical substitution and precipitation: Precipitation

Implementation Method 4

a plain bearing alloy layer is bonded to a surface of a backing steel sheet

Methodology Applied

Scientific EffectMetallurgical bonding: Welding

Data Source

PatentUS9683603B2Method for producing sliding member, sliding member, and substrate material of sliding member

Publication Date: 2017.06.20 TAIHO KOGYO CO LTD

AI summary

In a method, in which a plain bearing alloy layer is bonded to a surface of a backing steel sheet, and, a Bi-based overlay layer is then deposited on the plain bearing alloy layer by electroplating, replacement of Bi with the backing steel sheet and deposition of Bi on the backing steel sheet are prevented. Prior to the step of electroplating of the Bi-based overlay layer, the following metals and the like are formed on at least the back surface of the backing steel sheet. An electrochemically more noble metal than Bi, an electrochemically more base metal than Bi and capable of forming a passivation state, or resin.