You would like to carry out a galvanic corrosion study in the laboratory
What is galvanic corrosion?
Galvanic corrosion (or electrochemical corrosion) is a phenomenon that occurs when two or more dissimilar metals are brought into contact in the presence of an electrolyte (such as water containing salts, acids or bases). This creates an electrochemical cell, in which one metal acts as the anode (it corrodes) and the other as the cathode (it is protected).
Galvanic corrosion requires three conditions to occur. Firstly, two different metals must be present, such as aluminium and steel. Secondly, the two metals must be in direct electrical contact. Thirdly, there must be an electrolytic medium, such as salt water, humidity or any conductive solution.
In this context, it is the less noble metal, i.e. the most electrochemically reactive, that will degrade first: it is this metal that suffers galvanic corrosion.
The FILAB laboratory can help you study the galvanic corrosion of your materials
Why choose FILAB for galvanic corrosion studies?
FILAB, a laboratory made up of experts in metallurgy and steelmaking analysis, provides its knowledge and expertise to carry out galvanic corrosion study and electrochemical characterization of your metal parts.
To support you in the best conditions, the FILAB laboratory is approved Research Tax Credit (CIR) and accredited COFRAC ISO 17025.
ANALYTICAL RESSOURCES
The electrochemical techniques used to study galvanic corrosion include :
- measurement of the corrosion potential (Ecorr), which is used to determine which metal plays the role of anode or cathode in a galvanic couple. The lower the potential measured, the more likely the material is to corrode. This method is particularly useful for analysing multi-material assemblies.
- Galvanic current measurements involve bringing two metals into contact in an electrochemical cell and measuring the current generated naturally between them. This enables the intensity of galvanic corrosion to be quantified directly.
- the linear polarisation technique, also known as Tafel or potentiodynamics, which involves applying a controlled variation in potential around the equilibrium point, while measuring the current in response. This approach makes it possible to estimate the corrosion rate and the anodic and cathodic reactions involved.
- Electrochemical impedance spectroscopy (EIS), a non-destructive method that measures a system's resistance to an alternating current. It provides detailed information on the presence and effectiveness of protective barriers, such as passive films or coatings applied to materials.
Why carry out a galvanic corrosion study?
Evaluate the corrosion resistance of a metal or an alloy
Test the effectiveness of an anticorrosive coating or a paint
Characterize passive films on metal surfaces
Control the degradation of electrolytes, batteries or sensors
Study diffusive, capacitive or resistive behaviors in a system
Optimising performance and reducing costs
Encouraging innovation and compliance
Further information
our electrochemical analysis services
Measurement of the free potential (OCV) to evaluate the spontaneous electrochemical behavior of a metal in a given medium (water)
Study of galvanic coupling in order to analyze the interactions between two metallic materials to identify differential corrosion risks (ex: Zinc vs Steel)
Characterization of protective properties: barrier properties, porosity, water permeability, delamination, filamentary corrosion... ,
Impedance measurement to analyse the properties of the interfaces between a material and its electrochemical environment
Determination of the corrosion rate (LSV) in order to know the corrosion rate (mm/year) in various environments (salt water, pure water, inhibitor presence)
Measurement of corrosion potential (polarization curves) Potensiostat
Development of specific electrochemical tests (cathodic delamination, ACET, corrosion at the edges ...)
FAQ
The study enables us to anticipate the risks of premature degradation of metal assemblies, to optimise the choice of materials or coatings, and to validate metal pairs in demanding environments. It is essential in sectors such as aeronautics, space, medical and energy.
A range of complementary techniques are generally used, including :
- SEM-EDX to visualise the morphology of corroded areas and map the elements.
- XPS to study the oxidation state of surfaces.
- ICP-OES to quantify the elements dissolved in the electrolytes.
- And above all, electrochemical tests to measure corrosion potentials, currents and speeds.
The study can be carried out in different contexts:
- Failure in the field (localised corrosion, leakage, breakage, etc.)
- Validation of materials or assemblies before industrialisation
- Comparative study of coatings or surface treatments
- R&D project to simulate accelerated ageing
At FILAB, we offer tailor-made support:
- Advanced surface analysis (SEM-EDX, XPS, FTIR, etc.)
- Electrochemical testing (in collaboration with our R&D team)
- Interpretation of results and material/process recommendations
- Possibility of developing specific protocols according to your constraints
