Immersion Corrosion Testing
Micom Laboratories provides immersion corrosion testing services to help you evaluate how metals, alloys, and coated parts perform when fully or intermittently submerged in liquid environments. As an ISO/IEC 17025 accredited lab, we test to recognized standards and deliver clear, decision-ready data you can trust. We support aerospace, automotive, electronics, medical device, and general manufacturing teams across North America.
What Is Immersion Corrosion Testing?
An immersion corrosion test exposes specimens to a controlled solution to measure material loss, surface change, or coating breakdown over time. Immersion can be:
- Static immersion, where the sample remains continuously submerged in a solution
- Alternating immersion, where the sample cycles between wet and dry conditions to accelerate crevice, pitting, and underfilm corrosion.
Unlike cabinet tests such as salt spray, an immersion test for corrosion isolates the role of a specific fluid or chemistry, and enables precise control of temperature, concentration, agitation, and exposure time. Results typically include mass loss, calculated corrosion rates, and visual observations such as rusting, pitting, blistering, or discoloration.
When to Use an Immersion Test for Corrosion
Choose immersion corrosion testing when you need to:
- Select materials or coatings for service in water, seawater, brines, coolants, process fluids, or cleaning solutions.
- Compare candidate alloys or surface treatments before design freeze.
- Validate chemical compatibility for tanks, piping, fasteners, and fixtures that touch liquids.
- Investigate failures by reproducing field conditions under controlled parameters.
- Establish baseline corrosion rates to support life-prediction models or quality control.
Not sure if immersion corrosion testing is the right test for your project?
Immersion Corrosion Test vs. Salt Spray
| Criterion | Immersion Corrosion Testing | Salt Spray Testing (ASTM B117) |
| Primary purpose | Quantify material loss and observe corrosion in a defined liquid. | Comparative screening of coatings/finishes in a salt fog environment. |
| Typical standards | ASTM G31 (static), ASTM G44 (alternating immersion) | ASTM B117 |
| Exposure environment | Fully submerged or alternating wet/dry in a specific solution. | Continuous salt fog (typically 5% NaCl) at elevated temperature. |
| Chemistry & temperature control | High control of solution recipe, concentration, pH, inhibitors, and temperature set points. | Fixed salt solution and cabinet conditions; limited chemistry variation. |
| Key outputs | Mass loss, calculated corrosion rate (mg/y or mm/y), and visual observations. | Visual ratings, time-to-first-defect, comparative rank among samples. |
| Best for | Material selection, chemical compatibility, baseline corrosion rates, and reproducing a liquid service. | Fast comparative coating screens, QC checks, process control. |
| Mechanisms emphasized | General corrosion, pitting/crevice, underfilm (esp. with G44 cycles). | Surface rusting, blistering, and underfilm for some coatings. |
| Typical duration | Days to weeks, defined by acceptance criteria. | Hours to days for screening, sometimes longer for ranking. |
| When to pick this | You need the corrosion rate in a specific fluid, or want to mimic intermittent wetting with control. | You need fast, standardized comparative results across many samples. |
Standards We Test To
Micom Laboratories performs immersion corrosion testing to the most requested standards and can align with your internal or OEM procedures.
- ASTM G31 – Laboratory Immersion Corrosion Testing of Metals: Guidance for static immersion setups, solution control, specimen geometry, mass-loss measurements, and corrosion-rate calculations.
- ASTM G44 – Exposure of Metals and Coatings by Alternating Immersion: Cycles specimens through wet/dry periods to accelerate underfilm, crevice, and pitting mechanisms.
Have an internal method or OEM corrosion spec? Send it to us. We’ll review it, map it to our equipment, and, upon request, qualify a custom immersion corrosion test.
Our Capabilities & Test Conditions
At Micom Laboratories, we follow a rigorous, standardized process, as described in ASTM D412 standard documentation, to evaluate the tensile properties of vulcanized thermoset rubbers and thermoplastic elastomers.
Solutions We Work With
- Deionized water, NaCl solutions, synthetic seawater, glycols/coolants, detergents/cleaners, plating baths, customer-supplied process fluids
- Custom chemistries prepared to your concentration, pH, and inhibitor package
Control & Monitoring
- Temperature control: typical set points, ambient to 95 °C (higher on request)
- Concentration & pH verification at defined intervals
- Agitation/aeration available; alternating-immersion apparatus with programmable dwell times
- Covered baths to limit evaporation and contamination; sample racks/fixtures to maintain orientation and spacing.
Throughput
- Multiple baths run in parallel; 2 to 3 replicates per condition for statistical confidence
- Typical durations: 24 hours to 30+ days, depending on your acceptance criteria
Data You Can Expect
- Time-stamped logs (temperature, pH, conductivity as applicable)
- If required, photos at agreed intervals and at completion
- Clear traceability of specimens, lots, and solution batches
Note: Specimen preparation, cleaning, and evaluation are performed per ASTM G1 unless your specification requires otherwise.
Why Work With Micom Laboratories?
As a trusted materials testing laboratory, we have provided valuable test results and OEM-compliant documentation to many leading manufacturers such as Airbus, Bombardier, De Havilland, and more.
- ISO/IEC 17025 accredited by A2LA
- 25+ years of experience in material testing
- Customized testing to your needs
- Test consulting with qualified engineers
- Fast, reliable results
- Clear communication
- North American services
Related Corrosion Services
Strengthen your testing program with the following complementary tests:
- Salt Spray – ASTM B117
- Cyclic Corrosion Testing – ASTM D5894, ISO 11997-1, OEM Cyclic Corrosion Testing
- Humidity Resistance – ASTM D2247
- Modified Salt Spray – ASTM G85
- CASS – ASTM B368
- Coating Adhesion – ASTM D3359, ASTM D4541
Frequently Asked Questions About Immersion Corrosion Testing
How do I choose between ASTM G31 and ASTM G44?
Use G31 for continuous (static) immersion and quantitative mass-loss rates. Choose G44 when alternating wet/dry cycles better represent your service or when you need to accelerate pitting/underfilm mechanisms.
What solutions and temperatures can you run?
Common setups include NaCl brines, synthetic seawater, deionized water, coolants, and customer process fluids, typically from ambient up to 95 °C (higher on request).
How many specimens or replicates do I need?
Two to three replicates per condition are typical for statistical confidence; we’ll recommend counts based on your variability and acceptance criteria.
What will the report include?
Micom Laboratories’ reports include: corrosion rates (mg/y or mm/y), mass-loss tables, photos (if required), observations, full traceability of conditions/instruments, and any approved deviations. Raw data and bilingual reports are available.
Can you follow my OEM or internal spec?
Yes. You can share your document with us, and we’ll map it to our equipment and qualify a compliant immersion corrosion test for your project.