Solutions

Galvanic Couples & Metal Corrosion Chart

Explore the 26-metal galvanic compatibility chart (ASTM G82), calculate galvanic corrosion risks, and discover Filame's manufacturing expertise in springs, stampings, and multi-metal assemblies.

Galvanic corrosion (also termed bimetallic corrosion) is defined as the accelerated degradation resulting from physical contact between two dissimilar metals or alloys in the presence of an electrically conductive electrolyte.

In any conductive solution, an electrochemical galvanic series ranks metals according to their dissolution potential. When coupled directly, an electric current flows between them, accelerating the dissolution of the less noble alloy (the anode) while cathodically protecting the more noble metal (the cathode).

The potential differential (|ΔV|) indicates the direction of attack, but not its absolute magnitude. Electrolyte conductivity, operating temperature, assembly geometry, and particularly the relative surface area ratio between components are decisive factors.

Compatibility Matrix Risk Calculator Filame’s Expertise Industrial Applications Technical FAQ

Essential Conditions for Galvanic Corrosion

For galvanic corrosion to occur, three cumulative conditions must be met:

Dissimilar metals: An electrochemical potential differential creating an electromotive force.
Conductive electrolyte: Moisture, salt fog, condensation, or operating fluids acting as an ionic path.
Electrical continuity: Direct metallic contact allowing electronic charge transfer.

The Area Effect: Small Anode vs Large Cathode

For a given galvanic current between two metals, current density and dissolution rate on the less noble component increase dramatically when that anode has a small surface area:

Unfavorable case: A small anode (screw, rivet, spring) attached to a large cathode (stainless steel or copper plate) undergoes severe, accelerated perforation.
Favorable case: A large anode surrounding a small cathode (e.g., zinc-plated sheet with small stainless fastener) distributes dissolution across a broad area, remaining virtually harmless.

Galvanic Compatibility Matrix

Galvanic Couples Matrix Table (26 Metals & Alloys)

Electrochemical potential differences calculated in millivolts (|ΔV|) in an electrolyte of water + 2% NaCl vs Saturated Calomel Electrode (SCE). Click any cell to sync the CAD calculator and size your components.

Reference conditions: static water + 2% NaCl at ~20°C vs SCE (interpreted using ASTM G82 methodology)

Practically indifferent contact (|ΔV| ≤ 100 mV)

Metal B (row) is the corroded ANODE

Metal A (column) is the corroded ANODE

Metal B (Row) ↓ Metal A (Column) →	Platinum	Gold	Z6CN18-09 Passivated 18-10 Stainless	Silver	Mercury	N Nickel	UZ23N22 Arcap (CuNiZn)	U Pure Copper	UA10 Aluminum Bronze	UZ39Pb Free-cutting Brass	UE12 Tin Bronze	E Pure Tin	Pb Lead	AU4G Duralumin (2017A)	XC8 à 10 Mild Structural Steel	AS10G Cast Aluminum (AS10G)	A5 Pure Aluminum 99.5%	XC80 à 120 High-Carbon Spring Steel	AG4.5MC Duralinox (AlMg 5083)	Cd Cadmium Plating	Fe Pure ARMCO Iron	ASG Almasilium (6060 Al)	C Hard Chromium (active)	EZ25 Tin-Zinc Solder (75/25)	Z Zinc & Galvanized Steel	G Magnesium (AZ31)
Platinum	0	130	250	350	350	430	450	570	600	650	770	800	840	940	1000	1065	1090	1095	1100	1100	1105	1105	1200	1360	1400	1950
Gold	130	0	120	220	220	300	320	440	470	520	640	670	710	810	870	935	960	965	970	970	975	975	1070	1230	1270	1820
Passivated 18-10 Stainless Z6CN18-09	250	120	0	100	100	180	200	320	350	400	520	550	590	690	750	815	840	845	850	850	855	855	950	1110	1150	1700
Silver	350	220	100	0	0	80	100	220	250	300	420	450	490	590	650	715	740	745	750	750	755	755	850	1010	1050	1600
Mercury	350	220	100	0	0	80	100	220	250	300	420	450	490	590	650	715	740	745	750	750	755	755	850	1010	1050	1600
Nickel N	430	300	180	80	80	0	20	140	170	220	340	370	410	510	570	635	660	665	670	670	675	675	770	930	970	1520
Arcap (CuNiZn) UZ23N22	450	320	200	100	100	20	0	120	150	200	320	350	390	490	550	615	640	645	650	650	655	655	750	910	950	1500
Pure Copper U	570	440	320	220	220	140	120	0	30	80	200	230	270	370	430	495	520	525	530	530	535	535	630	790	830	1380
Aluminum Bronze UA10	600	470	350	250	250	170	150	30	0	50	170	200	240	340	400	465	490	495	500	500	505	505	600	760	800	1350
Free-cutting Brass UZ39Pb	650	520	400	300	300	220	200	80	50	0	120	150	190	290	350	415	440	445	450	450	455	455	550	710	750	1300
Tin Bronze UE12	770	640	520	420	420	340	320	200	170	120	0	30	70	170	230	295	320	325	330	330	335	335	430	590	630	1180
Pure Tin E	800	670	550	450	450	370	350	230	200	150	30	0	40	140	200	265	290	295	300	300	305	305	400	560	600	1150
Lead Pb	840	710	590	490	490	410	390	270	240	190	70	40	0	100	160	225	250	255	260	260	265	265	360	520	560	1110
Duralumin (2017A) AU4G	940	810	690	590	590	510	490	370	340	290	170	140	100	0	60	125	150	155	160	160	165	165	260	420	460	1010
Mild Structural Steel XC8 à 10	1000	870	750	650	650	570	550	430	400	350	230	200	160	60	0	65	90	95	100	100	105	105	200	360	400	950
Cast Aluminum (AS10G) AS10G	1065	935	815	715	715	635	615	495	465	415	295	265	225	125	65	0	25	30	35	35	40	40	135	295	335	885
Pure Aluminum 99.5% A5	1090	960	840	740	740	660	640	520	490	440	320	290	250	150	90	25	0	5	10	10	15	15	110	270	310	860
High-Carbon Spring Steel XC80 à 120	1095	965	845	745	745	665	645	525	495	445	325	295	255	155	95	30	5	0	5	5	10	10	105	265	305	855
Duralinox (AlMg 5083) AG4.5MC	1100	970	850	750	750	670	650	530	500	450	330	300	260	160	100	35	10	5	0	0	5	5	100	260	300	850
Cadmium Plating Cd	1100	970	850	750	750	670	650	530	500	450	330	300	260	160	100	35	10	5	0	0	5	5	100	260	300	850
Pure ARMCO Iron Fe	1105	975	855	755	755	675	655	535	505	455	335	305	265	165	105	40	15	10	5	5	0	0	95	255	295	845
Almasilium (6060 Al) ASG	1105	975	855	755	755	675	655	535	505	455	335	305	265	165	105	40	15	10	5	5	0	0	95	255	295	845
Hard Chromium (active) C	1200	1070	950	850	850	770	750	630	600	550	430	400	360	260	200	135	110	105	100	100	95	95	0	160	200	750
Tin-Zinc Solder (75/25) EZ25	1360	1230	1110	1010	1010	930	910	790	760	710	590	560	520	420	360	295	270	265	260	260	255	255	160	0	40	590
Zinc & Galvanized Steel Z	1400	1270	1150	1050	1050	970	950	830	800	750	630	600	560	460	400	335	310	305	300	300	295	295	200	40	0	550
Magnesium (AZ31) G	1950	1820	1700	1600	1600	1520	1500	1380	1350	1300	1180	1150	1110	1010	950	885	860	855	850	850	845	845	750	590	550	0

Platine vs Or |ΔV|: 130 mV

Click any cell to inspect this galvanic pair.

Galvanic Screening Calculator

Galvanic Compatibility & Corrosion Risk Calculator

Evaluate potential differential (|ΔV|), identify the sacrificial anode, and estimate galvanic driving force under reference conditions and geometric area ratios (Ac / Aa).

Preliminary Engineering Screening Note (ASTM G82 / ISO 8044 / DIN 50919:2022-02) : Preliminary screening based on open-circuit potential data in water + 2% NaCl vs SCE. Potential difference (ΔV) thresholds (≤150 mV marine, ≤250 mV industrial, ≤500 mV controlled) are legacy engineering screening heuristics and do not constitute MIL-STD-889D acceptance criteria. Actual galvanic corrosion depends on polarization kinetics, electrolyte conductivity, surface condition, and geometry. This screening does not substitute for environmental testing (ISO 9227) or application qualification.

1. Bimetallic Assembly Configuration

ASTM G82 / ISO 8044

1. Component A (Fastener, Spring, Clip)

Stainless steels (passivated / spring)

Titanium & superalloys (Inconel, Elgiloy)

Copper, brass & bronze alloys

Carbon & tempered spring steels

Aluminum alloys

Surface treatments & platings

2. Component B (Housing, Bracket, Chassis)

Stainless steels (passivated / spring)

Titanium & superalloys (Inconel, Elgiloy)

Copper, brass & bronze alloys

Carbon & tempered spring steels

Aluminum alloys

Surface treatments & platings

3. Operating Environment (Legacy ΔV Screen)

4. Geometric Area Ratio (Ac / Aa)

Cathodic to anodic area ratio (Ac / Aa): 1.0x

2. Electrochemical Diagnostic & Prescriptions

Potential Differential (|ΔV|)

Status Diagnostic

Low ΔV — Low galvanic driving force (preliminary screening)

Potential Differential (|ΔV|) 40 mV

Screening margin

-110 mV ≤ 150 mV (OK)

ANODE (Less Noble / Dissolution) +80 mV

Spring Stainless Steel 1.4310 / AISI 301 (Passivated)

1.4310 / AISI 301 (EN 10270-3)

Oxidation: M → Mᶻ⁺ + z e⁻ (Dissolution)

CATHODE (More Noble / Protected) +120 mV

Marine Stainless 1.4404 / 316L (Passivated)

1.4404 / AISI 316L (EN 10088-3)

Reduction: O₂ + 2H₂O + 4e⁻ → 4OH⁻ (Protected)

Area ratio factor (Ac / Aa) : 1.0x 1 : 1

Under cathodic diffusion control, anodic current density scales approximately with the Ac / Aa area ratio. Polarization effects, electrolyte resistance, and localized corrosion (ASTM G102) can alter actual local damage.

Technical recommendations

Low potential separation (|ΔV| within legacy screening threshold). Application-specific evaluation recommended.

ISO 9001 • FABRICANT EUROPÉEN

Get a quote for your multi-metal assembly specifications

Submit your 2D / 3D STEP drawings and material requirements for technical feasibility review and quotation.

Get a quote →

Filame Engineering

Filame's Expertise

How Filame integrates galvanic corrosion risk mitigation into tooling design, alloy selection, and serial manufacturing of springs and multi-metal stampings.

01 • Material Selection

Metallurgical Harmonization & Noble Alloys

Minimizing potential differences (|ΔV| ≤ 150 mV) through engineered material substitution.

Certified stamping and wire forming of stainless spring steels (1.4310 / 301, 1.4404 / 316L, 1.4568 / 17-7 PH) and nickel superalloys (Inconel 718, Inconel X-750) with complete EN 10204 3.1 mill traceability.

02 • Coatings & Treatments

High-Performance Barriers & De-Embrittlement

Neutralizing the galvanic cell via barrier coatings engineered for aggressive saline environments.

Zinc-Nickel plating (12–15% Ni per DIN 50979 / AMS 2417, up to >1,000h salt spray resistance), non-electrolytic zinc flake (Geomet / Dacromet per ISO 10683), and specification-compliant post-plating baking (ISO 24251-1 / AMS 2759/9) for high-tensile spring steel.

03 • Tooling Design

Dielectric Isolation & Multi-Metal Assembly

Eliminating electrical continuity between dissimilar metals within the mechanical joint.

Progressive die design integrating non-conductive washers/sleeves (PTFE, POM, PA66) and automated bi-metal joining on Bihler multi-slide machines and robotic riveting cells.

04 • Corrosion Kinetics

Geometric Surface Area Ratio Optimization

Systematic prevention of the high-risk 'small anode / large cathode' configuration.

Technical feasibility audit of client 3D STEP files and 2D blueprints by Filame's engineering office to optimize contact geometry, surface ratios, and electrolyte drainage.

Industrial Applications

Key Industries & Critical Bimetallic Couplings

Aerospace & Defense

Critical coupling: Carbon / Titanium / Aluminum

Carbon-fiber reinforced polymers (CFRP) and titanium fasteners form aggressive cathodic couples against 7075/2024 aluminum airframes. Filame manufactures certified precision springs and clips complying with EN 9100 quality demands.

Discover our expertise in this sector →

Automotive & E-Mobility

Critical coupling: Battery Packs & Steel / Aluminum Joints

Fastening aluminum battery housings with high-strength steel brackets under road-salt spray requires Zinc-Nickel (DIN 50979) or Geomet barrier coatings backed by systematic post-plating hydrogen de-embrittlement baking.

Discover our expertise in this sector →

Railway & Electrical Infrastructure

Critical coupling: Copper Catenaries & Steel / Brass Mounts

Copper/bronze electrical contact clips mounted onto galvanized steel bogies or carriages endure severe cyclic fatigue in wet outdoor air. Filame provides precision multi-slide stampings and selective-plated spring contacts.

Discover our expertise in this sector →

Energy, Marine & Offshore

Critical coupling: Saline Immersion & Stainless / Bronze Joints

In marine electrolytes (2–3.5% NaCl), the strict |ΔV| ≤ 150 mV design limit governs alloy selection. Filame forms high-grade corrosion-resistant metals including 316L stainless, Duplex 1.4462, and Inconel 718.

Discover our expertise in this sector →

Industrial Seals & Fluid Handling

Critical coupling: Inconel / Hastelloy Springs vs Steel Flanges & Graphite

Graphite gaskets and spring-energized PTFE seals trap conductive electrolytes within tight crevices. Filame manufactures continuous-length springs in noble superalloys (Inconel 718, Hastelloy C276, Elgiloy) to eliminate galvanic cells and maintain seal loading.

Discover our expertise in this sector →

Medical Devices & Surgical Instruments

Critical coupling: Titanium vs 1.4441 Stainless & Physiological Fluid

In physiological saline (0.9% NaCl at 37°C) and during autoclave steam cycles (134°C), galvanic couples are strictly prohibited to prevent toxic ion release (metallosis). Filame produces cleanroom-packaged springs in implant-grade 1.4441, 316LVM, and Elgiloy.

Discover our expertise in this sector →

Production capacities

Discover our manufacturing capabilities for springs and multi-metal stampings:

Questions & Answers

01 How does Filame's engineering team prevent galvanic corrosion in multi-metal assemblies ?

During the co-engineering phase with your 3D STEP files or 2D technical drawings, our metallurgical engineers evaluate the electrochemical potential difference (ΔV) between mating metals. We prescribe compatible alloy substitutions (such as Inconel or 316L stainless steel), high-performance barrier surface platings (Zinc-Nickel, chemical passivation EN 2516, Geomet), or dielectric isolation.

02 What is the risk of coupling a stainless steel spring or clip onto an aluminum chassis ?

Stainless steel possesses a noble cathodic potential (-50 mV) whereas structural aluminum is strongly anodic (-820 mV). In humid or saline environments, the potential delta exceeding 700 mV triggers severe localized pitting of the aluminum. If a small spring clip is mounted onto a large aluminum plate, the current density is diluted; conversely, a small aluminum part coupled to massive stainless steel suffers rapid structural perforation. Filame eliminates this risk with Zinc-Nickel or dielectric isolation.

03 What surface treatments does Filame provide for harsh salt spray environments ?

To safeguard stamped components and precision springs, Filame offers high-performance coatings: Zinc-Nickel (12-15% Ni, capable of achieving up to >1,000 hours in neutral salt spray testing per ISO 9227 depending on thickness and passivation), non-embrittling zinc flake coatings (Geomet/Dacromet per ISO 10683), pure electrolytic tinning for electrical contacts, and chemical passivation for stainless steels.

04 Can Filame manufacture production series meeting aerospace or automotive standards ?

Yes. Filame operates under ISO 9001 quality management and aligns with IATF 16949 and EN 9100 customer requirements. We manufacture medium to high volume runs on automatic high-speed presses up to 320 tonnes and Bihler multi-slide machines, providing EN 10204 3.1 material certificates, automated optical inspection (AOI) reports, and PPAP Level 3 documentation.

05 How can we submit 3D STEP drawings for engineering validation and an industrial quote ?

You can upload your CAD/STEP files or 2D technical drawings directly via our quote request form. Our engineering team reviews geometric tolerances, galvanic corrosion risks, and provides a clear manufacturing proposal.

Have another question ?

Ask our AI agent which has access to all of the information on the website.

→

Discover Filame

Galvanic Couples & Metal Corrosion Chart

Essential Conditions for Galvanic Corrosion

The Area Effect: Small Anode vs Large Cathode

Galvanic Couples Matrix Table (26 Metals & Alloys)

Galvanic Compatibility & Corrosion Risk Calculator

Get a quote for your multi-metal assembly specifications

Filame's Expertise

Metallurgical Harmonization & Noble Alloys

High-Performance Barriers & De-Embrittlement

Dielectric Isolation & Multi-Metal Assembly

Geometric Surface Area Ratio Optimization