How to Prevent and Clean Corroded Circuit Boards?

Although the circuit board rests underneath many essential pieces of equipment, over time, water, dust, and grime can find their way into your device. These contaminants can corrode your circuit board over a long time and may cause the device to get damaged permanently.

If you are interested in how to prevent and clean corroded circuit boards, please check and read the content below for more.

What Is Corrosion?

When oxygen bonds with a metal surface a process of oxidation occurs, this can produce rust and contribute to flakes of the metal surface breaking away. Because PCB traces and pads are made from metal such as copper they will always be at risk of some kind of corrosion.

Not every metal corrodes at the same rate. Some metals will corrode as soon as they are exposed to oxygen but others may not appear to ever corrode at all.

Causes of Corrosion on Circuit Boards

Rust makes the board vulnerable against short circuits, and a large amount of corrosion will result in the permanent damage of your device. So before we dive deep into tips to clean corrosion off motherboard or circuit board, it is essential to know what factors will cause such corrosion. It will help you take preventive measures against the corrosion build-up.

In most circuit boards, aluminum and copper are the primary metals used for all the conductive parts. Unfortunately, both of these metals are fairly reactive and can get corroded by getting in touch with airborne contaminants. Apart from air based contaminants, liquids can also cause corrosion on circuit boards. Both of these can be prevented by keeping your circuit board clean and away from such contaminants.

Types of PCB Corrosion

One can classify types of corrosion depending on the cause of the deterioration of the metal, and these are:

● General Attack Corrosion
● Galvanic Corrosion
● Localized Corrosion
● Inter-granular Corrosion
● Electrolytic Dendrite Formation
● Fretting Corrosion
● Environmental Cracking
● De-Alloying Corrosion
● Flow-Accelerated Corrosion
● High-Temperature Corrosion

Of the above, metal on PCBs are more likely to face the first five types of corruption.

How to Clean a Circuit Board of Corrosion?

Clean Corroded Circuit Boards

Over time, your PCB can accumulate more than just corrosion. Dirt, dust, and all kinds of grime can easily find its way into your electronic devices. Cleaning them can help prevent corrosion. But, if you have detected that your PCB already has corrosion, you can learn how to clean corrosion and use the following methods to avoid permanent damage.

1. Compressed Air

Use Compressed Air to Clean Corroded Circuit Boards

Compressed air is a fairly common tool used in electronics cleaning. For simple repairs, compressed air provides an unobtrusive way to free up any dust resting on the electronics or inside the machines and blow it out. Use short bursts to spray the air inside the ventilation ports. If you’re not satisfied with the dust removed, open the device with a screwdriver and work your way around the components, carefully cleaning the circuitry with the air.

2. Baking Soda

Use Baking Soda to Clean Corroded Circuit Boards

You can use baking soda to clear corrosions from your PCB. Baking soda contains sodium bicarbonate, It works on the grime and dust collection of the PCBs to break down the dirt into small particles. The mildly abrasive nature of the soda removes the corrosions without causing any side effects.

3. Deionized Water

Use Deionized Water to Clean Corroded Circuit Boards

When you use water to clean a circuit board, you must make sure it has no contaminants. The ions in regular water have conductive properties that degrade electronics. Meanwhile, deionized water has no contaminants or ions that cause damage.

4. Distilled Water

Use Distilled Water to Clean Corroded Circuit Boards

Distilled water triumphs over any other form of liquid when mixing your cleaning solution due to the absence of ions conductive to electric devices. Distilled water is specially treated to remove harmful contaminants, so it will not damage the printed board.

It also can become contaminated quickly by dirt found on your hands or in the air, so seal your reserve of distilled water when not in use and to avoid contact with your bare hands.

5. Isopropyl Alcohol

Use Isopropyl Alcohol to Clean Corroded Circuit Boards

Speaking of chemical-based cleaning agents, isopropyl alcohol or rubbing alcohol can remove all kinds of dirt, debris, flux, and rust from your circuit boards. Isopropyl alcohol is a great PCB cleaner because it is inexpensive and evaporates quickly. Compared to other cleaners used for similar purposes, alcohol contains fewer chemicals. It is important that isopropyl alcohol used to clean your circuit board is 90% or better. High-percentage isopropyl alcohol can cause adverse effects in contact with the body, so be sure to handle it with care and use latex gloves and goggles.

6. Thin, Soft-Bristle Brush

Use Thin, Soft-Bristle Brush to Clean Corroded Circuit Boards

A brush can be a super helpful tool when you're cleaning your circuit boards, as it can help you get in between all of the tiny components. It's crucial that you choose a brush with soft bristles. Size also plays a factor, as you need to be able to reach all the smallest spaces.

Most people like to go with a toothbrush or a paintbrush. They are sturdy and gentle, and most people already own at least one of them. Lint-free microfiber cloths are also good tools to have on hand to rub down and dry off your circuit board after you clean it.

7. A Blow Dryer or Hairdryer

Use Blow Dryer to Clean Corroded Circuit Boards

Sometimes you may require drying the printed circuit board since the liquids won't get away totally from the board. In this case, we thoroughly recommend you use a heat source such as hair or blow dryer for the purpose. Alternatively, you can ardently use a desk lamp or a pre-heated oven foil.

How Do You Prevent Corrosion on a Circuit Board?

From the above, it is clear that corrosion is primarily due to the presence of moisture or electrolytic contaminants on the PCB. Extreme environments such as industrial and humid atmosphere are liable to make PCBs highly susceptible to different types of corrosion. Preventing corrosion is possible by:

● Keeping the PCB dry
● Preventing electrolytes from wetting the PCB
● Covering the PCB with a conformal coating
● Removing flux residues effectively from the PCB

Older flux materials were notorious for generating chlorine or other harmful halogens, which led to the formation of pitting corrosion in copper traces unless the flux material was removed after the soldering process. However, organic acids in newer fluxes do not contain halogens, and they decompose at higher temperatures such as during reflow soldering. However, boards undergoing wave soldering may not reach the decomposing temperature, and the leftover flux residue may have to be manually cleaned thoroughly to prevent crevice corrosion.

It is largely possible to win the war against corrosion by preventing moisture or other liquids from reaching the PCB. There are many ways to achieve this, such as by placing the PCB inside an enclosure with a suitable IP rating.

In situations where it is not possible to enclose the PCB in an enclosure, conformal coatings can help. Different forms of conformal coatings, such as a simple solder mask, aerosol spray coatings, or epoxy coatings are all effective deterrents against corrosion. However, for PCBs carrying components that generate heat, such conformal coatings may have to be applied judiciously so as not to hamper heat management.

How to Remove Solder Flux From PCB?

Soldering occurs when two metals fuse using a heated metal with a low melting point that binds the two pieces together like glue. Flux is necessary for soldering to protect joints from metal oxides that inhibit a proper solder job. It does so by converting the metal oxides into salt and water that become locked in the flux once it hardens.

Solder flux can accumulate with a tainted yellow crust on the pins of chips where soldering has occurred. This issue is most common when a circuit board was not properly handled but is also an easily fixable issue. What you will need:

● Soft bristled brush
● Lint-free towel/microfiber cloth
● 90%+ anhydrous/rubbing alcohol

Wet your brush with rubbing alcohol and scrub the circuit board gently with your brush until the solder flux begins to disappear. Once you're satisfied with the look of your circuit board, dab it with a small towel or microfiber cloth. If you can use anhydrous alcohol or a commercial cleaner for flux and grease removal, this can speed up the process. However, substituting these products for a high percentage rubbing alcohol is the more affordable solution.

How to Remove Corrosion from Electronics After Water Damage?

How to Remove Corrosion from Electronics After Water Damage

When it comes to cleaning up corroded electronics after water damage, you have to be very careful. Not only can you damage the device further if you don't know what you are doing, but you could also potentially injure yourself. Remember: devices and liquid generally don't mix, so any time you are applying some of these cleaning solutions to a device, you need to be cautious. The average consumer should never attempt to repair a device without professional assistance. The best rule to keep in mind: When in doubt, take it to a professional! With that being said, here are a few helpful tips to keep in mind when dealing with deterioration and devices with water damage:

● To clean a device post-water damage, always remove any batteries,  power connectors, or power supplies first. This not only prevents harm to you, but also prevents any short-circuiting to the device. By doing this, you will also be exposing extra connectors that may already have corroded, so exercise caution.

● Look for any white or green "crusty" areas on the device, especially on the battery connectors, charging ports, circuit boards, logic boards, SIM card connectors, or any other major metal connectors on the device.

● Use cotton swabs and a cleaning solution such as isopropyl alcohol, baking soda and water, or even vinegar to clean it. Gently apply the solution to the affected area and wipe back and forth until the corrosion is removed. If necessary, leave some of the solution on the corroded area and wipe it off later.

● Dry your electronic device with a soft cloth or a hair dryer on a cool setting – do not use heat to dry out your device. Make sure your device is dried extremely well before attempting to replace the battery and turn the device on. Any water left in the device could cause additional water damage.

Conclusion

Since corrosion can completely damage a circuit board, cleaning it properly is highly important. And up above in this guide, we have not only discussed all the important information regarding circuit board corrosion, but we have also given a proper guide on How to prevent and clean corroded circuit boards. In addition, predicting corrosion in PCBs takes experience, and often, it is not possible to accurately predict where corrosion will occur, until the PCB actually starts to corrode. Fortunately, failure from corrosion does not happen immediately, and usually, there is considerable time available to address the cause effectively.