Cu-Ni Sintered Sliding Material With Grain-Boundary Wear Control
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Solution Overview
Problem
Existing Cu-based sintered sliding materials face issues with high wear and dimensional changes under high rotation rates and surface pressures, as well as high material costs due to excessive Ni content.
Innovation Solution
A Cu-based sintered sliding material composition with 7-35% Ni, 1-10% Sn, 0.9-3% P, and 0.5-5% C, featuring alloy grains with Cu-Ni as the main component, grain boundary phases with Ni and P, and dispersed pores, produced through a method involving powder mixing, press-molding, sintering at 760-900°C, and sizing to achieve a porosity of 13-28%, which enhances strength and wear resistance while minimizing dimensional changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If P is added to promote sintering and improve wear resistance, then wear resistance is improved, but dimensional change and variation during sintering become large
Solution Approach 1:
The patent optimizes the content of P to 0.01-3 mass% and C to 0.1-5 mass%, creating a balanced compositional parameter range that simultaneously achieves wear resistance improvement and dimensional stability during sintering
Solution Approach 2:
The patent creates a composite microstructure consisting of Cu-Ni-Sn alloy grains, Ni-P grain boundary phases, and free graphite, where each component contributes to either wear resistance or dimensional stability, resolving the contradiction through material composition design
2Strength
If spinodal decomposition treatment is used to strengthen the alloy, then hardness is improved, but the material does not fit with mating shaft from initial stage and wear progresses
Solution Approach 1:
The patent creates local quality differentiation by forming Ni-P phases specifically at grain boundaries while maintaining a softer Cu-Ni-Sn matrix in the grain interiors, providing both strength and wear compatibility in different locations
Solution Approach 2:
The patent controls the Sn content at 1-10 mass% and uses conventional sintering instead of spinodal decomposition, changing the microstructural parameters to achieve a balance between hardness and initial wear compatibility
3Strength
If Ni content is increased to improve strength and wear resistance, then mechanical properties are improved, but material cost increases
Solution Approach 1:
The patent optimizes Ni content to 7-35 mass% and combines it with Sn and P additions, creating a cost-effective compositional parameter range that achieves required mechanical properties without excessive Ni content
Solution Approach 2:
The patent creates a multi-element composite system (Cu-Ni-Sn-P-C) where Sn and P contribute to strengthening and wear resistance, allowing reduced Ni content while maintaining mechanical performance and lowering material cost
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 exhibits improved wear resistance and strength, reduced dimensional changes, and increased productivity, making it suitable for high rotation rate and surface pressure applications with controlled material costs.
Implementation Method 1
a sintering step of sintering the green compact to obtain a sintered body
Data Source
AI summary
The Cu-based sintered sliding material 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%.