How to Prevent Oxidation on Flexible PCBs
Date: 2025-09-27
Flexible PCBs are those bendy circuit boards you’ll find in smartwatches, car sensors, even wireless earbuds—super useful for fitting into tight spots. But here’s the catch: their copper parts hate moisture and air, and they’ll “rust” (we call that oxidation) if you don’t protect them. Oxidation makes the board glitch, slows down signals, or even kills it for good. The good news? Stopping it doesn’t need fancy tools—just a few simple steps.
First, coat the copper right. This is the easiest way to block oxidation. If you’re making something that needs to last (like a medical monitor or car safety part), go with ENIG—a coating with nickel and gold. It’s tough, works even if you bend the board a lot, and stays good for up to 2 years. For cheaper stuff, like a DIY IoT gadget, OSP works too—it’s cheap and thin, but don’t touch it with bare hands! Fingerprints break down the coating fast, so wear nitrile gloves. And if the board might get scratched (like in a tool), add solder mask—the green film you see on most PCBs; it keeps dust and moisture out.
Second, store them smart. You can’t just toss flexible PCBs in a drawer. Put them in vacuum-sealed bags—this sucks out the air that causes oxidation. Toss a silica gel packet inside too (the little white bags from shoe boxes) to soak up any moisture. Keep the bags in a cool, dry spot: 15-25°C (that’s 59-77°F) and 30-50% humidity. No hot attics or damp garages—those will ruin the coating fast. Also, use the oldest PCBs first: ENIG lasts 2 years, OSP only 3-6 months, so don’t let them sit around.
Third, handle with care when building. If you’re making the PCBs yourself, don’t leave the copper exposed for long. After etching the copper (the step where you make the circuit lines), coat it within 30 minutes—air is the enemy here. Wear nitrile gloves (latex leaves oil) to keep fingerprints off, and work in a clean space. Even a small dust particle can scratch the coating and let oxidation in.
That’s it—no rocket science. Do these three things, and your flexible PCBs won’t oxidize easily.
English
Wechat
+86 13670210335
+86 13670210335
E-mail