Gold-Cobalt Coating for Low-Friction Corrosion-Resistant Tool Elements
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Solution Overview
Problem
Existing machining and support elements for portable tools in agricultural, viticultural, and livestock farming applications face challenges with friction, corrosion, wear, and biocompatibility, particularly in tools like pruning shears and hoof shears, where known coatings do not adequately address these issues.
Innovation Solution
The use of a gold-cobalt alloy coating on at least a portion of the machining or support elements, providing improved tribological properties, reduced friction, enhanced corrosion resistance, and biocompatibility, with a composition ranging from 99% gold and 0.15%-1% cobalt, and a thickness of 0.1-20 µm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal coatings are used on machining elements, then corrosion resistance is provided, but friction and wear are not adequately reduced
Solution Approach 1:
The patent applies a composite coating system consisting of multiple layers: a nickel base layer, an intermediate gold layer, and an outer cobalt layer. This multi-layer composite structure combines the corrosion resistance of nickel with the low friction properties of gold and the wear resistance of cobalt, thereby simultaneously addressing all three issues of corrosion, friction, and wear that cannot be solved by a single material
Solution Approach 2:
The patent specifies precise parameter ranges for each coating layer to optimize performance: nickel layer thickness of 5-20 μm, gold layer of 0.5-5 μm, and cobalt layer of 0.1-2 μm. These controlled parameter variations allow the coating system to achieve the desired balance between corrosion resistance, friction reduction, and wear protection
2Duration of action of stationary object
If machining elements are made highly durable through metal coatings, then service life is extended, but cleaning and maintenance become more difficult
Solution Approach 1:
The gold intermediate layer in the coating system provides a distinctive yellow color that serves as a visual indicator for cleaning status. When the coating becomes contaminated with organic matter or sap, the color change is easily detectable, prompting timely cleaning. This visual signaling mechanism makes maintenance easier without compromising the durability provided by the multi-layer coating structure
3Object-generated harmful factors
If precious metal coatings like gold are applied to reduce friction, then tribological properties improve, but manufacturing cost increases
Solution Approach 1:
The gold layer is applied as a thin intermediate coating (0.5-5 μm) specifically at the contact interface between machining elements, where friction reduction is most critical. This localized application of precious material provides maximum tribological benefit while minimizing material cost, as the gold is concentrated only where it is most needed rather than coating entire components
Solution Approach 2:
The multi-layer composite structure allows the expensive gold layer to be sandwiched between cheaper nickel and cobalt layers. The nickel base provides corrosion resistance at lower cost, the thin gold intermediate layer provides friction reduction, and the outer cobalt layer provides wear resistance. This composite approach distributes costs across materials with different functions, making the overall system more cost-effective than using pure gold coatings
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 gold-cobalt alloy coating significantly reduces friction, enhances corrosion resistance, facilitates cleaning, and ensures biocompatibility, making the tools more suitable for agricultural and livestock applications.
Implementation Method 1
provides excellent tribological properties, including reduced friction
Implementation Method 2
good corrosion resistance
Data Source
Figure 1~3
AI summary
The invention relates to a machining element (4) or support element (2) for a handheld tool for agricultural, viticultural, arboricultural, or livestock farming applications, said element being made at least partially of metal and arranged to be movable for machining, wherein at least a portion of the machining element (4) or support element (2) comprises a gold-cobalt alloy coating. This type of coating provides good tribological properties, including reduced friction and good corrosion resistance. Furthermore, cleaning the machining or support elements for handheld tools according to the invention is facilitated. Finally, the machining or support elements are also biocompatible, making them particularly suitable for livestock applications, for example, for blades for sheep or goat hoof shears. The coating also has good wear resistance.