CuNiSn Intermediate Layer for Sliding Bearing Diffusion Barrier
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Solution Overview
Problem
Previous plain bearing composite materials face challenges with nickel-based diffusion barrier layers, which are difficult to deposit and prone to galling, leading to thin intermediate layers and thick overlays, affecting manufacturability and wear resistance.
Innovation Solution
A plain bearing composite material with a copper-tin or copper-zinc alloy bearing metal layer, a CuNiSn intermediate layer formed by PVD, and a thicker AlSn overlay, where the intermediate layer acts as both a diffusion barrier and improves tribological properties, reducing galling and wear while enhancing adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nickel-based diffusion barrier layers are used, then tin diffusion is prevented, but deposition difficulty and galling tendency increase
Solution Approach 1:
The patent changes the material composition parameters of the intermediate layer from traditional nickel-based alloys to copper-nickel-tin alloys with specific compositional ranges (Cu: 70-95 wt%, Ni: 3-20 wt%, Sn: 3-10 wt%). This parameter change enables the layer to maintain diffusion barrier functionality while improving depositability through PVD processes and reducing galling tendency.
Solution Approach 2:
The patent creates a composite intermediate layer combining copper, nickel, and tin elements with a controlled gradient structure. The copper-nickel-tin composite material exhibits synergistic properties: copper provides base metal compatibility, nickel offers diffusion barrier characteristics, and tin enhances surface properties and reduces galling, while the composite structure improves overall manufacturability.
2Reliability
If nickel-based intermediate layers are used, then tin diffusion is blocked, but galling increases requiring thicker overlays
Solution Approach 1:
The patent modifies the compositional parameters of the intermediate layer by incorporating tin (3-10 wt%) alongside nickel (3-20 wt%) in a copper matrix. This parameter change fundamentally alters the tribological properties, reducing galling tendency while preserving the diffusion barrier function, thereby eliminating the need for excessive overlay thickness.
Solution Approach 2:
The patent converts the potential harm of nickel-based layers (galling tendency) into a benefit by adding tin to the composition. The tin content transforms the intermediate layer's surface properties, making it more compatible with the tin-containing overlay and reducing galling, while the nickel component continues to provide diffusion barrier protection.
3Productivity
If intermediate layer thickness is reduced to 1-1.5 μm, then deposition time is reduced, but galling and wear resistance worsen
Solution Approach 1:
The patent changes the material parameters of the intermediate layer to copper-nickel-tin alloys, which have improved depositability through PVD processes. This enables efficient deposition at thicknesses of 1-10 μm while simultaneously reducing galling tendency and improving wear resistance, thus resolving the contradiction between deposition speed and performance.
Solution Approach 2:
The patent converts the limitation of thin intermediate layers (poor wear resistance and galling) into an advantage by using copper-nickel-tin composition. The specific alloying elements and their ratios provide both rapid depositability and superior tribological properties, making thin layers effective where traditional nickel layers failed.
4Strength
If harder bearing metal layers are used, then wear resistance improves, but seizure tendency increases and adaptability decreases
Solution Approach 1:
The patent changes the hardness parameter of the bearing metal layer by using lower-alloy copper-tin or copper-zinc compositions instead of high-alloy hard materials. This parameter change reduces seizure tendency and improves adaptability while compensating for wear resistance through the optimized copper-nickel-tin intermediate layer and tin-containing overlay configuration.
Solution Approach 2:
The patent introduces the copper-nickel-tin intermediate layer as a mediator between the softer bearing metal layer and the tin-containing overlay. This intermediate layer with its specific composition (Cu: 70-95 wt%, Ni: 3-20 wt%, Sn: 3-10 wt%) provides the necessary wear resistance and surface properties, allowing the bearing metal layer to remain soft and adaptable while preventing direct contact between dissimilar materials.
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 improves manufacturability, adaptability, and wear resistance by using a softer CuNiSn intermediate layer that reduces seizure and wear, allowing for thicker deposition and better particle compatibility, while maintaining low costs and good emergency running behavior.
Implementation Method 1
the intermediate layer (8) formed by physical vapor deposition (PVD) of CuNi(3-20)Sn(3-10)...which forms a diffusion barrier for tin
Implementation Method 2
with a directly tin-containing overlay formed on the intermediate layer by physical vapor deposition (PVD)...the intermediate layer (8) formed by physical vapor deposition (PVD)
Data Source
AI summary
The invention relates to a sliding bearing composite (2) having a support layer (4), in particular of steel, having a bearing metal layer (6) which is applied thereto and is composed of a bearing material based on a copper-tin or copper-zinc alloy and has a thickness of at least 100 Mm, with an intermediate layer (8) and a tin-containing sliding layer (10) formed directly on top of the intermediate layer (8) by physical vapour deposition (PVD), where the bearing material is formed by a copper-tin or copper-zinc alloy containing not more than 6% by weight of tin or not more than 25% by weight of zinc and the intermediate layer (8) is formed by physical vapour deposition (PVD) of CuNi(3-20)Sn(3-10), optionally with further constituents, and has a thickness of 1-10 µm.