Inert Anode Coating Composition for Molten Salt Corrosion Resistance

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Solution Overview

Problem

Metal inert anodes in aluminum electrolysis suffer from poor resistance to high-temperature molten salt corrosion, leading to a shortened service life and contamination of the aluminum product due to oxide layer formation and dissolution.

Innovation Solution

A coating composition for metal electrodes comprising NiFe2O4 (65%-75%) and a metal component (25%-35%, including Ni, Fe, and Y) is applied to the anode surface, enhancing corrosion resistance and conductivity, forming a protective film that extends the anode's service life to 35-45 weeks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal alloy anodes are used in aluminum electrolysis, then conductivity and mechanical properties are improved, but resistance to high-temperature molten salt corrosion deteriorates

Engineering Contradiction:

Improveconductivity and mechanical propertiesVSAvoidcorrosion resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies composite materials by combining metal alloy substrate with ceramic coating layers. The coating contains ceramic particles (such as Al2O3, SiO2, TiO2) embedded in a ceramic matrix, creating a composite structure that integrates the high conductivity of metal with the corrosion resistance of ceramics. This composite structure resolves the contradiction by providing both electrical conductivity and resistance to high-temperature molten salt corrosion.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent uses a ceramic coating layer as a protective thin film on the metal alloy anode surface. This coating acts as a barrier between the metal substrate and the corrosive molten salt electrolyte, preventing direct contact and corrosion while allowing electrical conductivity to pass through. The coating thickness and composition are optimized to maintain both protection and conductivity.

Inventive Principle:

Principle #30Flexible shells and thin films

2Object-affected harmful factors

If oxide ceramic anodes are used in aluminum electrolysis, then corrosion resistance is improved, but conductivity and mechanical properties deteriorate

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidconductivity and mechanical properties

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent creates a composite anode structure combining metal alloy substrate with ceramic coating. The metal substrate provides high conductivity and mechanical strength, while the ceramic coating provides corrosion resistance. This composite approach allows the anode to achieve both electrical conductivity and corrosion resistance, overcoming the limitations of pure oxide ceramic anodes.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies different material properties to different parts of the anode structure. The metal substrate provides conductivity and mechanical properties, while the ceramic coating layer provides corrosion resistance. This local differentiation of material functions allows the anode to simultaneously achieve both electrical performance and chemical resistance.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If pre-oxidation or surface spraying is applied to form protective oxide film, then corrosion resistance is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses a ceramic coating composition that can be applied through conventional coating processes. The coating contains ceramic particles and binding agents that form a protective layer when applied and cured. This approach provides corrosion resistance through a standardized coating process rather than complex pre-oxidation or surface spraying techniques.

Inventive Principle:

Principle #40Composite 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 coating significantly prolongs the anode's service life to 35-45 weeks and reduces metal impurities in primary aluminum to below 0.7%, addressing the issues of corrosion and contamination.

Implementation Method 1

A metal on a working surface of the metal anode is highly prone to an oxidation reaction with a newly generated oxygen in an electrolysis reaction

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

metal inert anodes have excellent conductivity and mechanical properties

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20260002277A1Metal electrode for aluminum electrolysis, coating composition thereof, and preparation method therefor

Publication Date: 2026.01.01 ZHENGZHOU NON FERROUS METALS RES INST CO LTD OF CHALCO

AI summary

A metal electrode for aluminum electrolysis, a coating composition of the metal electrode for aluminum electrolysis, and a method for preparing the metal electrode for aluminum electrolysis. The coating composition, by mass fraction, includes: NiFe2O4: 65%-75% and a metal component: 25%-35%. The chemical constituents of the metal component include: Ni, Fe, and Y.