Method for forming a cathodic protection coating on a turbomachine part
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Solution Overview
Problem
Existing methods for forming anti-corrosion coatings on turbomachine components, such as compressor or turbine shafts, face challenges in achieving uniform thickness and adequate corrosion protection, particularly with high-strength steels like Maraging 250 and 40CDV12, due to issues with electrophoretic deposition using aqueous electrolytes, which can lead to hydrogen embrittlement, pH variations, and insufficient thickness in a single step.
Innovation Solution
A method involving electrophoretic deposition using an organic electrolyte, followed by the formation of an inorganic matrix in the particle deposit's porosity, and mechanical compaction to achieve a controlled thickness of at least 40 µm in a single step, ensuring electrical conductivity and sacrificial protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrophoretic deposition using aqueous electrolyte is used, then deposition can be performed, but hydrogen embrittlement occurs and pH variations cause insufficient thickness
Solution Approach 1:
The patent changes the fundamental parameter of the electrolyte from aqueous to organic (alcoholic). This parameter change eliminates water electrolysis and hydrogen embrittlement while maintaining the electrophoretic deposition mechanism. The organic electrolyte allows controlled deposition without the harmful side effects of aqueous systems.
Solution Approach 2:
The patent converts the potential harm of using aqueous electrolytes (hydrogen embrittlement, pH variations) into benefit by using organic electrolytes. The organic electrolyte system avoids these harmful effects entirely while providing superior deposition control and thickness uniformity.
2Manufacturing precision
If electrophoretic deposition with aqueous electrolyte is used, then deposition can be performed, but significant local pH variations occur leading to resin precipitation
Solution Approach 1:
The patent changes the electrolyte from aqueous to organic, fundamentally altering the chemical environment. This eliminates water-based pH variations and resin precipitation issues, providing stable deposition conditions throughout the coating process.
3Quantity of substance
If electrophoretic deposition is used to achieve thick deposit, then multiple deposition steps are required, but this lengthens and complicates the process
Solution Approach 1:
The patent changes the electrolyte composition to organic, which enables achieving thick deposits (20 µm or greater) in a single deposition step. This single-step process eliminates the need for multiple deposition cycles required by aqueous electrolyte systems.
Solution Approach 2:
The organic electrolyte system allows continuous deposition of thick coatings in one uninterrupted step, maintaining useful deposition action throughout the entire process without interruption for intermediate steps.
4Manufacturing precision
If electrophoretic deposition with aqueous electrolyte is used, then deposition can be performed, but water electrolysis causes bubbling phenomenon affecting deposit homogeneity
Solution Approach 1:
The patent changes the electrolyte from aqueous to organic, eliminating water electrolysis and the associated bubbling phenomenon. This parameter change ensures homogeneous deposit formation without interruptions from gas evolution.
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 method provides a homogeneous, thick, and electrically conductive coating that effectively combats corrosion, eliminating the need for multiple deposition steps and avoiding substrate damage, with improved environmental compatibility and simplified process.
Implementation Method 1
the deposition on the substrate of cathodic protection particles of the substrate, this deposition being carried out by electrophoresis from an organic electrolyte comprising at least said particles
Implementation Method 2
a heat treatment of drying of the deposit impregnated by the impregnation composition
Implementation Method 3
a densification by mechanical compaction of the deposit, after the heat treatment of drying, in order to make said deposit electrically conductive
Data Source
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AI summary
The invention relates to a method for forming a cathodic protection coating on a substrate (1) forming a turbomachine part, comprising at least: - the deposition, on the substrate, of particles (11) for the cathodic protection of the substrate, this deposition being effected by electrophoresis from an organic electrolyte (10) comprising at least said particles, and - the formation of an inorganic matrix in a porous area of the particle deposit thus produced, comprising at least: • impregnating said deposit with an impregnating composition, • thermally drying the deposit impregnated with the impregnating composition, and • densifying the deposit by mechanical compaction, after the thermal drying treatment, so as to make said deposit electrically conductive.