Will the PCB circuit boards "rust" after long-term use?

Will the PCB circuit boards "rust" after long-term use?

I am the editor of ONESEINE. Every day, I receive various soul-searching questions from engineers in the background. Today, I specially selected this high-frequency question to answer-"Editor, the circuit board in our equipment has been used for more than a year. Recently, I found that the solder pads have turned black. Is this board rusted? Can it be rescued?"

1. The truth about the "rust" of the circuit board

The copper foil on the circuit board is like the "blood vessels" of the human body. Once oxidation corrosion occurs, the signal will be distorted at the least, and the whole machine will be paralyzed at the worst! Three common killers:

Humidity during the rainy season (when humidity is greater than 60%, copper foil begins to oxidize in 72 hours)

Salt in sweat (leaving fingerprints during assembly is like a "chronic poison")

Sulfide attack (sulfur released by rubber foot pads/seals)

2. ONESEINE anti-rust black technology

We provide protection solutions for more than 3,000 customers, with a combination of core processes:

1. Double insurance for surface treatment

Immersion gold process: 2 micron nickel layer + 0.05 micron gold layer, creating a "golden bell"

Selective OSP: in the plug-in part

2. Three-proof coating black technology

Using polyurethane coating, through three processes of spray gun/pen coating/dip coating, it can achieve:

Coating thickness 0.1-0.3mm precise control

Resistant to extreme temperature changes of -40℃~125℃

Salt spray test>48 hours

3. Full protection of storage and transportation

Vacuum aluminum foil packaging (including desiccant + humidity indicator card)

Constant temperature and humidity warehouse (temperature 23±2℃, humidity 45%±5%)

III. Emergency rescue guide

If the circuit board is found to have signs of oxidation, handle it according to the severity:

Symptoms First aid plan

Slightly darkening Isopropyl alcohol wiping + partial re-coating of three-proof paint

Local greening Return to the factory for deplating + chemical silver precipitation treatment

Large area corrosion It is recommended to replace and check environmental problems

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