The Corrosion-Resistant PCB is designed to withstand exposure to corrosive substances—such as saltwater (marine use), industrial chemicals (acids, alkalis), and humidity—preventing degradation of traces, components, and solder joints. Corrosion (e.g., rust on copper traces or tin whisker growth) disrupts electrical conductivity, leading to PCB failure. This specialized PCB is critical for marine electronics, chemical processing equipment, wastewater sensors, and coastal infrastructure, where standard PCBs degrade within months.

Its corrosion resistance stems from advanced plating and substrate materials. Copper traces are plated with corrosion-resistant metals: ENIG (Electroless Nickel Immersion Gold) is most common—nickel (5-10 μm) acts as a barrier, while gold (0.1-0.5 μm) provides a conductive, corrosion-proof surface. For extreme environments (e.g., saltwater), thicker gold plating (1-3 μm) or palladium-nickel (Pd-Ni) alloy is used, as Pd-Ni resists saltwater and sulfur compounds. The PCB substrate uses FR-4 with a hydrophobic coating or specialty materials like ceramic (alumina) or PTFE, which do not absorb corrosive liquids.

Solder masks and finishes further enhance protection. The solder mask is a thick (25-50 μm) epoxy or polyimide layer with low water absorption (<0.1% after 24 hours in water), covering all traces except component pads. Some designs add a secondary overcoat of PTFE or silicone, creating a chemical barrier. Component selection is also critical—using corrosion-resistant components (e.g., stainless steel connectors, hermetically sealed ICs) that match the PCB’s durability.

Testing involves rigorous exposure to corrosive environments. The PCB is subjected to ASTM B117 salt spray tests (5% NaCl mist at 35°C for 1000+ hours) or chemical immersion (e.g., 10% sulfuric acid for 24 hours). After testing, traces are inspected for corrosion (no visible pitting), and electrical resistance is measured—must remain stable (<10% change from initial values). Solder joint integrity is checked via X-ray or thermal cycling (-40°C to 125°C for 1000 cycles) to ensure no cracking.

For applications like offshore wind turbine sensors or chemical plant control systems, the Corrosion-Resistant PCB ensures long-term reliability—withstanding corrosive elements that would destroy standard PCBs.