2026 Technical Exchange Meeting Summary (pdf)
The second annual Atmospheric Corrosion Technical Exchange Meeting (TEM) brought together engineers and scientists from the naval, aerospace, and offshore wind industries for a half-day virtual session hosted by Pierre Morel of Acuity Corrosion Technology at Luna Labs. Presenters from the U.S. Navy, Northrop Grumman, and Sirris shared results from the field.
One message ran through every session: continuous, real-time monitoring reveals corrosion behavior that conventional inspection simply cannot detect. Long-standing rules of thumb used to plan maintenance often turn out to be wrong when checked against real data.
Here are five findings that stood out:
1. The 80% humidity rule doesn't hold at sea
Maintenance planners have long applied a “factor of two” when estimating how much more corrosive a shipboard environment is versus land. A multi-year NAWCAD effort set out to quantify that relationship for the first time, deploying Acuity LS sensors and coupons across two aircraft carrier classes and a guided missile cruiser for up to 14 months.
The results upended two assumptions at once. On land, the conventional 80% relative-humidity threshold for corrosion onset holds up. On ships, the majority of corrosion events occurred below that threshold in conditions traditional time-of-wetness models would call non-corrosive. Exterior ship locations scored roughly 4x more corrosive than the most aggressive U.S. land site studied, not the 2x planners had assumed.
For naval assets, that means risk models built on the 80% threshold are underestimating real exposure.
2. Every humid landing leaves a Mark
A Northrop Grumman team moved sensors from baseline hangar and coastal sites onto an operational flying aircraft – two in the wheel wells, two in the underside “canoe” compartment – and captured about ten months of flight data.
The pattern was striking in its clarity: every humid-environment landing produced a measurable corrosion event, and every arid landing produced none. At a humid touchdown, relative humidity spikes and stays elevated while galvanic corrosion current rises in parallel; at an arid landing, RH spikes but drops away with no corrosion response. Because the aircraft is hangared between flights, the landing itself is the primary corrosion driver. Continuous data now makes flight-by-flight corrosion accounting possible.
3. The Offshore splace zone is hard to protect
In the WILLOW project, an EU-funded offshore wind initiative, Sirris deployed instrumented frames across five zones of a monopile-like structure 500 meters off the Belgian North Sea coast. A clear takeaway from the first coupon retrieval: corrosion mechanism and rate differ dramatically by zone, so no single inspection or protection strategy fits the whole structure.
The splash zone, which has no cathodic protection, is the highest-risk area, dominated by pitting. It is also tough on sensors, with intermittent wetting and salt residue that defeat conventional time-of-wetness instruments. The Acuity LS surface-conductivity measurement was deployed there on a “let’s see if it survives” basis and ran for more than 12 months, including a field battery and lid change. The data also showed a humidity-only pitting model overestimated pit depth by roughly 3x pointing to conductivity as the missing variable.
4. It's the drying, not the wetting, that drives cracking
A NAWCAD program developed a modified accelerated test for stress corrosion cracking (SCC) in 7075-T6 aluminum, swapping standard six-hour salt-fog events, so severe that every coating failed immediately with no differentiation, for a repeatable, automatable 10-minute fog. The refined method cleanly separated coating performance and revealed that crack growth accelerated preferentially during the 60% RH drying hold, identifying the drying mechanism as the critical SCC driver.
Acuity research saw the same thing using the Insight SL and DL test systems for combined mechanical and corrosion loading. In SCC-susceptible 7075-T6, the drying transition itself produced sharp spikes in crack growth rate, an effect absent in SCC-resistant 7050-T7, confirming it as a genuine corrosion mechanism rather than a mechanical artifact. The work also showed aluminum-rich sacrificial primers significantly outperform non-chromate primers, and that a galvanic couple at a fastener dramatically accelerates cracking
5. Conditions-based maintenance is happening now
Across naval aviation, aerospace, and offshore infrastructure, the presentations made one thing clear: continuous monitoring is no longer a future ambition. It is delivering insights today such as counter-intuitive corrosion hotspots, flight-by-flight accounting, and zone-specific structural risk.
Acuity’s own roadmap reflects what these deployments are revealing, including a refined six-category environmental severity framework, the Insight SL and DL test systems, a hot-swappable battery pack for multi-sensor airframe deployments (validated on a C-130), and remote cellular telemetry now in final development.
Three Themes, one direction
If the day had a common thread, it was this:
- Assumptions must be tested. Fixed humidity thresholds, assumed severity multipliers, and visual inspection consistently fell short against real-world data.
- The drying transition is a critical driver of corrosion damage from ships and aircraft to offshore splash zones and laboratory SCC chambers.
- Condition-based maintenance is already operational, and continuous monitoring is what makes it possible.
The community plans to reconvene for a third meeting. If you work in atmospheric corrosion monitoring or mitigation, we’d value your input on timing, topics, and format — share your thoughts in this brief survey.
Contact our corrosion team with questions or to inquire about Acuity corrosion solutions.
