Anodized Aluminum Propeller Coating Abrasion Resistance
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Solution Overview
Problem
Conventional aluminum propellers for small-sized boats face issues with abrasion and deformation due to collisions with floating objects and abrasive environments, leading to reduced propulsion power and potential corrosion, with existing hard anodized treatments providing insufficient abrasion and deformation resistance.
Innovation Solution
A propeller made from an aluminum alloy with a Vickers hardness of 60-95 Hv, coated with an anodic oxide layer of 20-100 μm thickness and 300-450 Hv hardness, produced using die casting and anodic oxidation, providing enhanced abrasion and deformation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a painted film is provided on the propeller surface for corrosion protection, then corrosion resistance is improved, but the propeller edge becomes dull and water dissipation deteriorates
Solution Approach 1:
The patent changes the physical and chemical parameters of the protective coating by using anodized aluminum oxide instead of organic paint. The anodized layer provides both corrosion protection and maintains edge sharpness, resolving the contradiction between protection and performance.
Solution Approach 2:
The patent creates a composite structure with the aluminum propeller body and an anodized aluminum oxide coating layer. This composite provides both the mechanical properties of aluminum and the protective properties of aluminum oxide, eliminating the need for separate paint applications.
2Shape
If a thick hard anodized aluminum layer is formed to prevent edge dulling, then edge sharpness is improved, but the layer becomes too thick and may cause other issues
Solution Approach 1:
The patent optimizes the anodization parameters to achieve a coating thickness of 5-20 μm, which is sufficient to maintain edge sharpness and provide protection without being excessively thick. This parameter optimization resolves the contradiction between edge sharpness and coating thickness.
3Weight of moving object
If the propeller is made of aluminum alloy for light weight and low cost, then weight and manufacturing cost are reduced, but abrasion resistance and deformation resistance are insufficient
Solution Approach 1:
The patent creates a composite structure where the aluminum alloy base provides light weight and the anodized aluminum oxide layer provides abrasion and deformation resistance. This composite approach resolves the contradiction between weight and strength.
Solution Approach 2:
The patent applies the hard anodized coating specifically to the surface of the propeller where abrasion and deformation occur, while the bulk aluminum alloy maintains its light weight properties. This local quality enhancement resolves the contradiction between overall weight and surface strength.
4Shape
If conventional hard anodized treatment is applied with thin layer (about 15 μm), then edge sharpness is maintained, but abrasion resistance and deformation resistance are insufficient
Solution Approach 1:
The patent changes the anodization parameters including electrolyte composition, temperature, and treatment time to achieve a coating thickness of 5-20 μm with enhanced hardness and structural properties, providing both edge sharpness and sufficient abrasion/deformation resistance.
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 prevents chipping and plastic deformation of propeller blades, maintains propulsion power, and offers excellent durability against abrasive environments, including sandy waters, while ensuring corrosion protection.
Implementation Method 1
an anodic oxide coating of the aluminum alloy provided so as to cover a surface of the propeller body
Data Source
AI summary
A propeller for watercraft having excellent abrasion resistance and deformation resistance includes a propeller body having a blade and a hub portion, the propeller body being composed of an aluminum alloy and having a Vickers hardness of no less than about 60 Hv and no more than about 95 Hv; and an anodic oxide coating of the aluminum alloy provided so as to cover a surface of the propeller body. The anodic oxide coating has a thickness of no less than about 20 μm and no more than about 100 μm. Preferably, the anodic oxide coating has a hardness of no less than about 300 Hv and no more than about 450 Hv.