Copper Alloy Sliding Element for Engine Wear Resistance
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Solution Overview
Problem
Modern internal combustion engines require sliding elements with improved wear resistance and reduced lead content, while maintaining low costs and high machinability, as existing copper-zinc alloys are expensive and insufficiently durable under modern engine stresses.
Innovation Solution
A copper alloy with a chromium content of at least 0.2% and a sum of titanium and chromium content greater than or equal to 0.2%, containing hard phases that form up to 3% of the friction pairing, along with optional magnesium, aluminum, and iron for enhanced mechanical properties and corrosion resistance, and a lead content of up to 0.8% by weight, optimized for low friction and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lead is added to improve machinability, then machinability is improved, but environmental compliance and material cost are worsened
Solution Approach 1:
The patent replaces expensive and harmful lead with a combination of cheaper, environmentally friendly elements (Ca, Sr, Ba) that provide similar machinability benefits without the toxic effects. This substitution maintains manufacturing ease while eliminating the harmful substance.
Solution Approach 2:
The patent changes the chemical composition parameters by introducing alkaline earth metals (Ca, Sr, Ba) in specific quantities (0.01-3.0 wt% each) to replace lead's function. This parameter change achieves the same machinability improvement through a different chemical mechanism that is environmentally compliant.
2Reliability
If copper content is increased to improve sliding properties, then sliding properties are improved, but material cost is worsened
Solution Approach 1:
The patent creates a composite alloy system combining copper (50-90 wt%) with zinc, aluminum, and small amounts of alkaline earth metals. This composite approach maintains the beneficial sliding properties of high-copper alloys while reducing overall copper content and cost through synergistic interactions between the alloying elements.
Solution Approach 2:
The patent introduces localized improvements to the alloy structure through small additions of Ca, Sr, and Ba (0.01-3.0 wt% each) that specifically enhance sliding properties at critical interfaces without requiring high overall copper content. This localized quality improvement reduces the need for expensive copper while maintaining performance.
3Strength
If alloying elements are added to improve mechanical properties, then strength is improved, but manufacturing complexity is worsened
Solution Approach 1:
The patent uses small, controlled amounts of alloying elements (Ca, Sr, Ba at 0.01-3.0 wt% each) rather than large quantities. This partial action approach provides sufficient strength improvement without creating excessive manufacturing complexity or requiring complex processing procedures.
Solution Approach 2:
The alkaline earth metals (Ca, Sr, Ba) serve multiple functions simultaneously: they improve machinability, enhance strength, and provide environmental compliance. This multi-functionality reduces the need for multiple separate alloying additions, thereby simplifying the overall alloy composition and manufacturing process.
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 copper alloy exhibits a low coefficient of friction, improved wear resistance, and stable setting behavior, with high thermal conductivity and resistance to stress relaxation, making it suitable for steel friction partners and reducing thermally induced tensions.
Implementation Method 1
The copper alloy exhibits a low coefficient of friction, improved wear resistance, and stable setting behavior
Implementation Method 2
The copper alloy exhibits a low coefficient of friction, improved wear resistance, and stable setting behavior
Implementation Method 3
At least one fraction of precipitates can be present, the precipitates having a volume-equivalent spherical diameter of at least 1.0 μm
Implementation Method 4
A sliding element made from the copper alloy according to the invention is resistant to stress relaxation
Implementation Method 5
A sliding element made from the copper alloy according to the invention has high thermal conductivity
Data Source
AI summary
The invention relates to a sliding element made of a copper alloy containing the following components (in wt.%): 2.0 to 3.0% Ni, 0.45 to 1.0% Si, up to 1.5% Ti and/or Cr, optionally 0.05 to 1.5% Co, optionally 0.05 to 0.1% each of Mg, Al, and Fe, optionally 0.01 to 0.1% Pb, optionally 0.002 to 0.01% P, balance Cu and unavoidable impurities, wherein the ratio of the sum of the Ni content [Ni], Ti content [Ti] and Cr content [Cr] to the Si content [Si] is: 4.3 ≤ ([Ni] + [Ti] + [Cr])/[Si] ≤ 6.5.