Iridium Alloy Electrode with Anodized Oxide Coating

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Solution Overview

Problem

Implantable medical electrodes made of platinum and palladium alloys are expensive and prone to polarization, which reduces their effectiveness, and existing methods for forming iridium oxide coatings are costly and inefficient.

Innovation Solution

An electrode with an alloy of iridium, cobalt, and iron, coated with a conductive oxide layer formed by anodization in an electrolytic solution, which reduces polarization and provides corrosion protection without the need for expensive sputter deposition processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If platinum and palladium alloys are used for electrodes, then corrosion resistance and biocompatibility are improved, but manufacturing cost increases significantly

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The electrode uses a composite structure combining a platinum or palladium alloy core with an iridium oxide coating layer. This composite approach provides the corrosion resistance of precious metals while reducing the amount of expensive material needed, thereby lowering manufacturing costs.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention replaces expensive platinum or palladium alloy electrodes with a more cost-effective iridium-containing alloy electrode coated with iridium oxide. This substitution uses less expensive materials to achieve comparable or superior performance, significantly reducing manufacturing costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If platinum and palladium alloys are used for electrodes, then radiopacity is improved for verification during implantation, but electrode polarization increases reducing effectiveness

Engineering Contradiction:
ImproveradiopacityVSAvoidelectrode polarization
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The electrode combines a radiopaque core material (platinum or palladium alloy, or iridium-containing alloy) with a conductive iridium oxide coating. The core provides radiopacity for imaging verification, while the oxide coating reduces electrode polarization, creating a composite structure that eliminates both issues simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the surface properties of the electrode by coating it with iridium oxide, which has different electrochemical properties than the underlying metal alloy. This parameter change in surface composition reduces electrode polarization while maintaining the radiopacity of the core material.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If sputter deposition is used to form iridium oxide coating, then conductive oxide layer is formed, but manufacturing cost increases and deposition efficiency decreases

Engineering Contradiction:
Improveconductive oxide layer formationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention replaces the expensive sputter deposition process with an electrochemical anodization method. This substitution uses electricity and electrolytic solutions to form the iridium oxide coating, eliminating the need for expensive sputter deposition equipment and reducing manufacturing costs while maintaining coating quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The anodization process allows the iridium-containing alloy electrode to form its own protective oxide coating through electrochemical reactions in an electrolytic solution. This self-service approach eliminates the need for external deposition of iridium material and complex sputter deposition systems.

Inventive Principle:
Principle #25Self-service

4Object-generated harmful factors

If sputter deposition is used to form iridium oxide coating, then electrode polarization is reduced, but material waste increases due to deposition on non-target surfaces

Engineering Contradiction:
Improveelectrode polarizationVSAvoidiridium material waste
Core Design Contradiction:
Object-generated harmful factorsVSLoss of substance

Solution Approach 1:

The invention replaces sputter deposition with electrochemical anodization, which forms the oxide coating in situ on the electrode surface through controlled electrochemical reactions. This eliminates material waste on non-target surfaces since the oxide forms only where the electrode is immersed in the electrolytic solution, significantly reducing iridium material waste.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 significantly reduces electrode polarization, enhances corrosion resistance, and lowers production costs by forming the oxide layer directly from the alloy, ensuring effective and cost-efficient medical device performance.

Implementation Method 1

An anodized iridium oxide film may be formed by depositing a layer of iridium on an electrode surface, and then anodizing the iridium layer in an electrolytic solution to form the iridium oxide film

Methodology Applied
Scientific EffectAnodization: Anodising

Implementation Method 2

anodizing the iridium layer in an electrolytic solution to form the iridium oxide film

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 3

The layer of iridium may be deposited by sputter deposition

Methodology Applied
Scientific EffectSputter deposition: Sputtering

Implementation Method 4

A thermal iridium oxide film may be formed by the thermal decomposition of an iridium salt

Methodology Applied
Scientific EffectThermal decomposition: Thermolysis

Implementation Method 5

A sputtered iridium oxide film is formed by direct sputter deposition of iridium oxide onto the surface by sputtering iridium in an oxygen plasma environment

Methodology Applied
Scientific EffectSputter deposition in plasma: Sputtering

Data Source

PatentEP3256205B1Implantable electrode
Publication Date: 2021.03.24 CARDIAC PACEMAKERS INC
  • EP3256205B1 patent drawingFigure 1
  • EP3256205B1 patent drawingFigure 2

AI summary

An electrode for use with an implantable medical device includes an alloy and a conductive oxide layer on a surface of the alloy. The alloy includes iridium and at least one of cobalt and iron. The conductive oxide layer includes iridium oxide. The conductive oxide layer has a thickness greater than about 5 nanometers.