View Latest Blog Entries
Testing & Assessment Certification Standard & Regulation Aging Wires & Systems Maintenance & Sustainment Protection & Prevention Management Conference & Report Research Miscellaneous Arcing
Popular Tags
Visual Inspection High Voltage AS50881 MIL-HDBK MIL-HDBK-525 FAR Electromagnetic Interference (EMI) AS4373 Maintenance FAR 25.1707 Wire System Arcing Damage
All Tags in Alphabetical Order
2021 25.1701 25.1703 abrasion AC 33.4-3 AC 43 Accelerated Aging accessibility ADMT Aging Systems AIR6808 AIR7502 Aircraft Power System aircraft safety Aircraft Service Life Extension Program (SLEP) altitude arc damage Arc Damage Modeling Tool Arc Fault (AF) Arc Fault Circuit Breaker (AFCB) Arc Track Resistance Arcing Arcing Damage AS22759 AS22759/87 AS23053 AS29606 AS4373 AS4373 Method 704 AS50881 AS5692 AS6019 AS6324 AS81824 AS83519 AS85049 AS85485 AS85485 Wire Standard ASTM B355 ASTM B470 ASTM D150 ASTM D2671 ASTM D8355 ASTM D876 ASTM F2639 ASTM F2696 ASTM F2799 ASTM F3230 ASTM F3309 ATSRAC Attenuation Automated Wire Testing System (AWTS) Automotive Avionics backshell batteries bend radius Bent Pin Analysis Best of Lectromec Best Practice bonding Cable Cable Bend cable testing Carbon Nanotube (CNT) Certification cfr 25.1717 Chafing Chemical Testing Circuit Breaker circuit design Circuit Protection cleaning clearance Coaxial cable cold bend collision comparative analysis Compliance Component Selection Condition Based Maintenance Conductor Conductor Testing conductors conduit Connector connector installation Connector rating connector selection connector testing connectors contacts Corona Corrosion Corrosion Preventing Compound (CPC) corrosion prevention Cracking creepage D-sub data analysis data cables degradat Degradation Delamination Derating design safety development diagnostic Dielectric breakdown dielectric constant Dimensional Life disinfectant Distributed Power System DO-160 dry arc dynamic cut through E-CFR electric aircraft Electrical Aircraft Electrical Component Electrical Power Electrical Testing Electrified Vehicles Electromagnetic Interference (EMI) Electromagnetic Vulnerability (EMV) Electrostatic Discharge EMC EMF EMI EN2235 EN3197 EN3475 EN6059 End of Service Life End of Year Energy Storage engines Environmental Environmental Cycling environmental stress ethernet eVTOL EWIS certification EWIS Component EWIS Design EWIS Failure EWIS sustainment EWIS Thermal Management EZAP FAA FAA AC 25.27 FAA AC 25.981-1C FAA Meeting failure conditions Failure Database Failure Modes and Effects Analysis (FMEA) FAQs FAR FAR 25.1703 FAR 25.1707 FAR 25.1709 Fault fault tree Filter Line Cable Fixturing Flammability fleet reliability Flex Testing fluid exposure Fluid Immersion Forced Hydrolysis fuel system fuel tank ignition Functional Hazard Assessment functional testing Fundamental Articles Fuse Future Tech galvanic corrosion Glycol Gold Gold plating Green Taxiing Grounding hand sanitizer handbook Harness Design harness protection hazard Hazard Analysis health monitoring heat shrink heat shrink tubing high current high Frequency high speed data cable High Voltage High Voltage Degradation HIRF History Hot Stamping Humidity Variation HV connector HV system ICAs IEC 60851 IEC60172 IEEE immersion insertion loss Inspection installation installation safety Instructions for Continued Airworthiness insulating material insulating tape Insulation insulation breakdown insulation resistance insulation testing interchangeability IPC-D-620 ISO 17025 Certified Lab ISO 9000 J1673 Kapton Laser Marking life limit life limited parts Life prediction life projection Lightning lightning protection liquid nitrogen lithium battery lunar Magnet wire maintainability Maintenance Maintenance costs Mandrel mean free path measurement mechanical stress Mechanical Testing MECSIP MIL-C-38999 MIL-C-85485 MIL-DTL-17 MIL-DTL-23053E MIL-DTL-3885G MIL-DTL-38999 MIL-E-25499 MIL-HDBK MIL-HDBK-1646 MIL-HDBK-217 MIL-HDBK-454 MIL-HDBK-516 MIL-HDBK-522 MIL-HDBK-525 MIL-HDBK-683 MIL-STD-1353 MIL-STD-1560 MIL-STD-1798 MIL-STD-464 MIL-T-7928 MIL-T-7928/5 MIL-T-81490 MIL-W-22759/87 MIL-W-5088 MIL–STD–5088 Military 5088 modeling moon MS3320 NASA NEMA27500 Nickel nickel plating No Fault Found OEM off gassing Outgassing Over current Overheating of Wire Harness Parallel Arcing part selection Partial Discharge partial discharge at altitude Performance physical hazard assessment Physical Testing polyamide polyimdie Polyimide-PTFE Power over Ethernet power system Power systems predictive maintenance Presentation Preventative Maintenance Program Probability of Failure Product Quality PTFE pull through Radiation Red Plague Corrosion Reduction of Hazardous Substances (RoHS) regulations relays Reliability Research Resistance Revision C Rewiring Project Risk Assessment S&T Meeting SAE SAE Committee Sanitizing Fluids Secondary Harness Protection separation separation distance Separation Requirements Series Arcing Service Life Extension Severe Wind and Moisture-Prone (SWAMP) Severity of Failure shelf life Shield Shielding Shrinkage signal signal cable Silver silver plated wire silver-plating skin depth skin effect Small aircraft smoke Solid State Circuit Breaker Space Certified Wires Splice standards Storage stored energy superconductor supportability Sustainment System Voltage Temperature Rating Temperature Variation Test methods Test Pricing Testing testing standard Thermal Circuit Breaker Thermal Endurance Thermal Index Thermal Runaway Thermal Shock Thermal Testing tin Tin plated conductors tin plating tin solder tin whiskering tin whiskers top 5 Transient Troubleshooting TWA800 UAVs UL94 USAF validation verification video Visual Inspection voltage voltage differential Voltage Tolerance volume resistivity vw-1 wet arc white paper whitelisting Winding wire Wire Ampacity Wire Bend Wire Certification Wire Comparison wire damage wire failure wire performance wire properties Wire System wire testing Wire Verification wiring components work unit code

New Means to Assess Corrosion Susceptibility

Testing & Assessment

Key Takeaways
  • Outgassing can impact conductor plating. There are several means to assess wire corrosion susceptibility.
  • The latest version of AS4373 (Rev F) provides three new ways to assess corrosion.
  • These include more rapid means to quantitatively and qualitatively assessment techniques.

Low outgassing materials are critical for space applications. As one might imagine, a small, enclosed space with outgassing materials is not an ideal environment.

To that end, space system developers have always sought insulation constructions with low outgassing properties. In past articles, Lectromec has covered the developments of the methods and materials used to reduce outgassing. Here, we examine the latest testing techniques for these materials.


Red Plague is a particular degradation mechanism that impacts silver-plated copper materials and was first documented decades ago. Rather than repeat what has been covered in other articles, you can find that information here:

In aerospace applications, silver-plated conductors are commonplace, as are the fluorinated polymers that insulate them. Those wires/cables at the highest risk of red plague are those with ETFE based insulations/jackets.

Low Fluoride

The first method to limit the impact of Red Plague was to quantify and set a maximum threshold on the amount of fluoride that can be extracted through a test method. This method, AS4373 Method 608, has become a foundational test for those wires with the moniker “low fluoride”. In this test, the insulation is stripped from the conductor and submerged in Type I water at 70oC for a week. The solution is then measured to determine the amount of extracted fluoride.

For the current constructions that use this method to determine fluoride evolution, the threshold is set to 40ppm. At this level, the likelihood of red plague development is very low.

Method 610

In the latest revision of the AS4373, there are three new methods for the assessment of conductor corrosion and red plague susceptibility outgassing. These new methods provide good alternatives to the fluoride evolution method in 608. The benefit of these methods is that they provide a quicker means of achieving a measurement than the week necessary to perform 608.

The first method is method 610 – “Wire Corrosion Potential, Red Plague”. In this method, 10g of completed wire (conductor and insulation) are placed into a beaker and submerged in water. Two electrodes, one silver and one copper are attached to the beaker cap such that they will make contact with the solution in the beaker and extend through the cap to allow for connection to an external measurement device. The beaker is then capped, and the electrodes are connected to a 10k Ohm resistor to complete the circuit.

Visual Representation of the Setup for Method 610
The development of the new assessment methods came after several years of research funded by the United States Air Force Research Lab (AFRL). This figure shows the physical setup of wire corrosion potential test (Method 610).

During the next three days, the voltage across the resistor is measured. Those samples with fluoride evolution will show a progressive voltage potential increase between the silver and copper electrodes showing greater ionization of the fluid. Those samples less likely to show red plague will have a lower voltage measurement across the resistor.

This method is not as exact as method 608, but it does provide a quicker alternative that can be used for screening or quality control once baseline values have been established.

Method 611

The next method for wire assessment is the “Wire Corrosion Potential – Corrosion Sensitivity” test. There is a fair bit of overlap between this method and the 608 test method described above. In this test, the insulation is separated from the conductor and submerged in Type 1 water for 48 hours at 90oC. After this exposure, several measurements are performed including:

  • Extracted fluoride (same as 608).
  • Conductivity of solution (to determine the extractable conductive species from the insulation).
  • Contaminant Anions (e.g., acetates, bromides, chlorides, nitrates, sulfates, etc.) are present in the solution.

For those interested in understanding all of the elements that can be extracted from an insulation when exposed to high temperatures, this is one method for that evaluation.

Method 612

The last method discussed here is the “Wire Corrosion Potential – Vapor Phase Corrosion”. In comparison to the other methods discussed here, this test method provides a “qualitative assessment of a material’s propensity to release volatile, corrosive species at elevated temperatures, especially in low pressure and vacuum applications.” In this test, a short length of insulated wire/cable (not separated from the conductor) is wrapped with a tin conductor, and placed into a sealed vacuum tube (at 200 torr).

The sealed sample is then placed into a 200oC oven and visually examined every 24 hours. The qualitative review is a quick means to rank the stability/volatile fluoride content of insulated wires.

Wrap Up

These methods have been developed to ascertain the red plague susceptibility of the silver-plated conductor and the outgassing of fluoride. Each of these has a particular application. Where specificity and measurable values are required, then methods 608 and 611 should be used, otherwise, method 610 and 612 can be employed. How these methods will be employed in the industry (whether as part of product specifications or employed as part of batch quality assessments) remains uncertain, but they create viable options to quickly obtain results.

As always, if you are looking for a lab to perform these tests, contact Lectromec. Our ISO 17025:2017 accredited lab is ready to help.

Michael Traskos

Michael Traskos

President, Lectromec

Michael has been involved in wire degradation and failure assessments for more than a decade. He has worked on dozens of projects assessing the reliability and qualification of EWIS components. Michael is an FAA DER with a delegated authority covering EWIS certification and the chairman of the SAE AE-8A EWIS installation committee.