Ceramic Conductor Marine Cathodic Protection
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Solution Overview
Problem
Existing corrosion protection systems for marine propulsion devices using non-sacrificial anodes are vulnerable to damage due to their exposure in underwater environments, particularly when made of expensive materials like platinum, which are prone to contact with debris and impact.
Innovation Solution
A corrosion protection system utilizing a ceramic conductor made of iridium, tantalum, and titanium compounds attached to an electrically insulative support member, positioned close to the submergible portion of the marine propulsion device, providing a robust and durable alternative to traditional anodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional non-sacrificial anodes made of expensive materials like platinum are used, then corrosion protection effectiveness is improved, but vulnerability to damage from debris and impact increases
Solution Approach 1:
The patent applies composite materials by combining ceramic conductor materials (such as tungsten, molybdenum, or their alloys) with mounting structures designed to withstand impact. The ceramic conductor provides the necessary electrical conductivity and corrosion protection effectiveness, while the composite construction and mounting approach enhance resistance to damage from debris and impact.
2Reliability
If sacrificial anodes are used, then corrosion protection is provided, but frequent replacement is required
Solution Approach 1:
The patent employs a non-sacrificial anode system where the ceramic conductor material does not consume itself to provide protection. Instead, the system uses external power sources or galvanic coupling with more active metals to provide protective current, allowing the anode structure to remain intact and functional for extended periods without replacement, thereby eliminating the frequent replacement requirement of sacrificial anodes.
3Strength
If ceramic conductor is used, then durability and resistance to damage are improved, but cost of materials increases
Solution Approach 1:
The patent applies local quality by using ceramic conductor materials specifically at critical locations where durability and resistance to damage are most needed, such as at the anode surface exposed to water and debris. The ceramic coating or conductor is applied locally to the metal substrate rather than requiring bulk ceramic construction, thereby achieving the desired durability while minimizing the quantity and cost of expensive ceramic materials required.
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 ceramic conductor effectively inhibits galvanic corrosion by resisting damage and maintaining operational effectiveness over time, even in harsh underwater conditions, without the need for frequent replacement.
Implementation Method 1
a ceramic conductor used as an electrode in a marine cathodic protection system used to inhibit the formation of a galvanic circuit
Implementation Method 2
the combination of a stainless steel propeller with an aluminum housing of a marine propulsion device can result in the disintegration of the aluminum housing
Data Source
AI summary
A ceramic conductor is supported by an electrically insulative support member for attachment directly to a marine propulsion drive and for use as either an anode or electrode in a corrosion prevention system. The ceramic conductor is received within a depression formed in a surface of the electrically insulative support member and the exposed surface of the ceramic conductor can be offset from or coplanar with an exposed surface of the electrically insulative support member. The ceramic conductor can comprise oxides of iridium, tantalum and titanium that are formed as a coating on a titanium substrate.