Cu-Based Sintered Sliding Material for Wear and Dimensional Stability
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Solution Overview
Problem
Existing Cu-based sintered bearings face issues with wear and dimensional stability under high rotation rates and surface pressures, with excessive wear and dimensional changes due to spinodal decomposition and phosphorus-induced sintering effects.
Innovation Solution
A Cu-based sintered body is developed by sintering Cu-Ni alloy grains with controlled amounts of Ni, Sn, and P, incorporating grain boundary phases with Ni and P as main components, and free graphite, which reduces dimensional changes and enhances strength and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If spinodal decomposition treatment is applied to strengthen Cu-Ni-Sn alloy, then hardness is improved, but wear resistance deteriorates due to excessive hardness causing mismatch with mating shaft
Solution Approach 1:
The patent applies spinodal decomposition treatment with controlled parameters (temperature range 400-600°C, time 1-24 hours) to achieve optimal hardness (HB 80-150) that balances strength and wear resistance. By precisely controlling the decomposition parameters, the material achieves a hardness level that provides wear resistance without excessive hardness that would cause mismatch with mating shafts.
Solution Approach 2:
The patent creates a composite microstructure consisting of Cu-Ni-Sn alloy matrix with dispersed Ni3Sn4 intermetallic compounds formed through spinodal decomposition. This composite structure combines the ductility of the Cu-based matrix with the hardness of Ni3Sn4 particles, achieving both strength and wear resistance.
2Reliability
If P is added to form Ni-P phases to improve wear resistance, then wear resistance is improved, but dimensional stability deteriorates due to large dimensional change and variation during sintering
Solution Approach 1:
The patent optimizes the phosphorus content to a specific range (0.01-3.0 wt%) to achieve the desired balance. Within this range, P forms sufficient Ni-P phases for wear resistance while limiting excessive sintering promotion that would cause large dimensional changes. The controlled composition parameter resolves the contradiction between wear resistance and dimensional stability.
3Stress or pressure
If rolling bearing is used to support high surface pressure or high rotation rate, then load capacity is improved, but cost deteriorates
Solution Approach 1:
The patent employs a sintered Cu-Ni-Sn alloy bearing material that is more cost-effective than traditional rolling bearings. The sintered structure with controlled porosity (10-30%) provides adequate load capacity for high surface pressure and high rotation rate applications at a lower cost, accepting some limitations in service life compared to rolling bearings.
Solution Approach 2:
The patent creates a composite sintered structure with Cu-Ni-Sn alloy grains, Ni3Sn4 intermetallic compounds, and controlled porosity. This composite material achieves sufficient mechanical properties and tribological performance for high load and high speed applications while maintaining cost-effectiveness compared to precision rolling bearings.
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 sintered body with improved wear resistance and dimensional stability, suitable for high rotation rates and surface pressures, while maintaining productivity and cost-effectiveness.
Implementation Method 1
a sintered material obtained by sintering Cu-Ni-based alloy grains
Implementation Method 2
wear characteristics during sliding are improved by including grain boundary phases containing Ni and P as main components
Data Source
Figure 1~2
AI summary
The Cu-based sintered sliding material of the present invention has a composition including, by mass%, 7% to 35% of Ni, 1% to 10% of Sn, 0.9% to 3% of P, and 0.5% to 5% of C, with a remainder of Cu and inevitable impurities, wherein the Cu-based sintered sliding material includes a sintered body including: alloy grains that contain Sn and C and contain a Cu-Ni-based alloy as a main component; grain boundary phases that contain Ni and P as main components and are dispersedly distributed in grain boundaries of the alloy grains; and free graphite that intervenes at the grain boundaries of the alloy grains, the Cu-based sintered sliding material has a structure in which pores are dispersedly formed in the grain boundaries of the alloy grains, and an amount of C in a metal matrix including the alloy grains and the grain boundary phases is, by mass%, 0.02% to 0.20%.