Layered Friction Material Coating for Corrosion and Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional friction materials sintered with copper plating have inferior corrosion resistance due to pinholes, leading to rust and reduced bonding strength, and thick copper plating is costly and dimensionally inconsistent.
Innovation Solution
A friction material with a specific coating layer structure comprising a first layer of Cu, Ni, and Fe, and a second layer of Cu and Ni, where Cu content increases and Ni content decreases across the layer, improving corrosion resistance and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper plating of not less than 30 μm in coating thickness is used to fill pinholes and improve corrosion resistance, then corrosion resistance is improved, but coating thickness variation increases, production time increases, and costs increase
Solution Approach 1:
The coating layer is divided into multiple layers with different compositions and functions. The first layer (1-6 μm) contains Cu, Ni, and Fe to provide base corrosion protection and fill pinholes. The second layer (9.5-24.0 μm) contains Cu and Ni with controlled gradients to provide enhanced corrosion resistance. This segmentation allows each layer to be optimized for its specific function, achieving adequate corrosion protection with reduced total thickness and better uniformity control
Solution Approach 2:
The second coating layer incorporates a compositional gradient where Cu content increases and Ni content decreases from the first coating layer interface toward the outer surface. This local variation in composition allows the inner portion to provide corrosion resistance while the outer portion provides oxidation resistance and adhesion, achieving superior overall performance without requiring excessive total thickness
2Reliability
If copper plating of not less than 30 μm in coating thickness is used to improve corrosion resistance, then corrosion resistance is improved, but plating time increases and costs increase
Solution Approach 1:
The coating is segmented into functional layers that can be applied efficiently. The first layer is applied to a controlled thickness of 1-6 μm to fill pinholes, then the second layer is applied to 9.5-24.0 μm for enhanced protection. This segmented approach allows for better process control and reduced total plating time compared to applying a single 30 μm layer
Solution Approach 2:
The invention changes the compositional parameters of the coating layers, specifically controlling Cu content at 1-60 atom% and Ni content at 10-95 atom% in the first layer, and Cu content at 5-60 atom% and Ni content at 40-95 atom% in the second layer. These parameter optimizations enable achieving superior corrosion resistance with reduced thickness and shorter plating time
3Reliability
If excessively thick plating is applied, then corrosion resistance is improved, but peeling of the plating occurs
Solution Approach 1:
The second coating layer features a compositional gradient where Cu content increases and Ni content decreases from the interface with the first layer toward the outer surface. This gradient structure prevents abrupt compositional changes that cause stress concentration, thereby preventing peeling while maintaining adequate thickness for corrosion resistance (9.5-24.0 μm)
Solution Approach 2:
The coating system uses a composite structure with two distinct layers having different compositions. The first layer (Cu, Ni, Fe) provides base adhesion and corrosion protection, while the second layer (Cu, Ni gradient) provides enhanced corrosion resistance with controlled stress distribution. This composite approach prevents peeling by distributing mechanical stresses across layers with gradually changing properties
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 material achieves superior corrosion resistance and adhesion, reducing rust and peeling issues while maintaining dimensional accuracy and reducing production costs.
Implementation Method 1
a sintered material superior in rust-prevention, made by diffusion bonding of a metallic lining material to an iron back plate via copper coating through sintering
Implementation Method 2
the friction material superior in corrosion resistance... bonding a back plate and a friction part in a friction material via a specific coating layer
Data Source
AI summary
A friction material comprises an Fe part which contains Fe as a main component, a coating layer formed on a surface of the Fe part, and a friction part formed on a surface of at least a part of the coating layer, and the coating layer comprises a first coating layer and a second coating layer which have a specific average thickness and a specific component in order from Fe part side, and in the second coating layer, in order of positions at which the thickness is 20%, 40%, 60% and 80% of the second coating layer from the side of the first coating layer to the side opposite thereto, a Cu content increases and a Ni content decreases.