Although the circuit board is located beneath many critical pieces of equipment, water, dust, and grime can find their way into your device over time. Prolonged exposure to these contaminants can corrode your circuit board and potentially render your device useless.
If you want to learn more about how to prevent and clean corroded circuit boards, please see and read the content below.
What Is Corrosion?
When oxygen bonds with a metal surface, an oxidation process occurs, which can result in rust and the separation of metal surface flakes. Because PCB traces and pads are made of metals such as copper, they are always susceptible to corrosion.
Every metal corrodes at a different rate. Some metals corrode as soon as they come into contact with oxygen, while others do not appear to corrode at all.
Causes of Corrosion on Circuit Boards
Rust makes the board vulnerable to short circuits, and excessive corrosion will cause permanent damage to your device. So, before we get into how to clean corrosion off a motherboard or circuit board, it’s important to understand what causes such corrosion. It will assist you in taking preventative measures against corrosion buildup.
Aluminum and copper are the primary metals used in most circuit boards for all conductive parts. Unfortunately, both of these metals are fairly reactive and can corrode when exposed to airborne contaminants. In addition to airborne contaminants, liquids can corrode circuit boards. Both of these can be avoided if your circuit board is kept clean and free of contaminants.
Types of PCB Corrosion
Types of corrosion can be classified based on the cause of metal deterioration, and these are as follows:
● General Corrosion Attack
● Galvanic Corrosion
● Corrosion on a Localized Scale
● Intergranular Corrosion
● Formation of Electrolytic Dendrites
● Corrosion of Fretting
● Environmental Cracking
● De-Alloying Corrosion
● Flow-Induced Corrosion
● Corrosion at High Temperatures
Metal on PCBs is more likely to experience the first five types of corruption.
How To Clean a Circuit Board of Corrosion?
Your PCB can accumulate more than just corrosion over time. Dirt, dust, and other debris can easily get into your electronic devices. Cleaning them can aid in corrosion prevention. However, if you’ve already noticed corrosion on your PCB, you can use the following techniques to clean it up and prevent further damage.
1. Compressed Air
Compressed air is a fairly common tool for cleaning electronics. For simple repairs, compressed air provides an unobtrusive way to blow out any dust that has accumulated on the electronics or inside the machines. Spray the air inside the ventilation ports in short bursts. If the dust hasn’t been removed completely, open the device with a screwdriver and work your way around the components, carefully cleaning the circuitry with air.
2. Baking Soda
Baking soda can be used to remove corrosion from your PCB. Baking soda contains sodium bicarbonate, which works on PCB grime and dust collection to break the dirt down into small particles. The soda’s mild abrasiveness gets rid of the rust without causing any other problems.
3. Deionized Water
When cleaning a circuit board with water, make sure it is free of contaminants. Regular water ions have conductive properties that degrade electronics. Meanwhile, deionized water contains no harmful contaminants or ions.
4. Distilled Water
Due to the absence of ions that are conductive to electric devices, distilled water triumphs over any other type of liquid when mixing your cleaning solution. Distilled water has been specially treated to remove harmful contaminants, ensuring that it will not damage the printed board.
It can also be quickly contaminated by dirt on your hands or in the air, so keep your reserve of distilled water sealed when not in use and avoid contact with your bare hands.
5. Isopropyl Alcohol
Isopropyl alcohol or rubbing alcohol, for example, can remove all types of dirt, debris, flux, and rust from your circuit boards. Isopropyl alcohol is an excellent PCB cleaner because it is inexpensive and quickly evaporates. Alcohol contains fewer chemicals than other cleaners used for similar purposes. It is critical that the isopropyl alcohol used to clean your circuit board be at least 90% pure. When high-percentage isopropyl alcohol comes into contact with the body, it can have negative effects, so handle it with caution and wear latex gloves and goggles.
6. Thin, Soft-Bristle Brush
A brush can be a very useful tool when cleaning your circuit boards because it allows you to get in between all of the tiny components. It’s critical to use a brush with soft bristles. Size is also important because you must be able to reach all of the smallest spaces.
The majority of individuals prefer using a toothbrush or paintbrush. They are durable and gentle, and the majority of individuals already possess at least one. Lint-free microfiber cloths are also useful for rubbing down and drying your circuit board after cleaning it.
7. A Blow Dryer or Hairdryer
Because liquids do not always evaporate completely from the printed circuit board, you may need to dry it. In this case, we strongly advise you to use a heat source, such as a hair or blow dryer. Alternatively, a desk lamp or pre-heated oven foil can be used.
How Do You Prevent Corrosion on a Circuit Board?
It is clear from the foregoing that corrosion is caused primarily by the presence of moisture or electrolytic contaminants on the PCB. Extreme environments, such as industrial and humid environments, are known to make PCBs highly susceptible to various types of corrosion. Corrosion can be avoided by doing the following:
● Keeping the PCB dry
● Preventing electrolytes from wetting the PCB
● Applying a conformal coating to the PCB
● Effectively removing flux residues from PCBs
Unless the flux material was removed after the soldering process, older flux materials were notorious for generating chlorine or other harmful halogens, resulting in pitting corrosion in copper traces. Organic acids in newer fluxes, on the other hand, do not contain halogens and decompose at higher temperatures, such as during reflow soldering. However, wave-soldered boards may not reach the decomposing temperature, and the leftover flux residue may need to be manually cleaned thoroughly to prevent crevice corrosion.
By preventing moisture or other liquids from reaching the PCB, it is possible to win the war against corrosion. There are numerous methods for accomplishing this, such as placing the PCB inside an IP-rated enclosure.
Conformal coatings can be useful when it is not possible to enclose the PCB in an enclosure. Conformal coatings of various types, such as simple solder masks, aerosol spray coatings, or epoxy coatings, are all effective corrosion deterrents. However, for PCBs carrying heat-generating components, such conformal coatings may need to be applied with caution so as not to interfere with heat management.
How To Remove Solder Flux From PCB?
When two metals are soldered, a heated metal with a low melting point binds the two pieces together like glue. Flux is required for soldering to protect joints from metal oxides that obstruct proper soldering. It does this by turning the metal oxides into salt and water, which are then locked in the flux when it hardens.
Solder flux can form a tainted yellow crust on chip pins where soldering has occurred. This problem is most common when a circuit board is not handled properly, but it is also a simple fix. You will require the following items:
● Soft bristled brush
● lint-free towel or microfiber cloth
● 90%+ anhydrous/rubbing alcohol
Wet your brush with rubbing alcohol and gently scrub the circuit board until the solder flux disappears. When you’re happy with the appearance of your circuit board, dab it with a small towel or microfiber cloth. If you can remove flux and grease with anhydrous alcohol or a commercial cleaner, you can speed up the process. However, substituting these products for a high percentage of rubbing alcohol is a less expensive option.
How To Remove Corrosion From Electronics After Water Damage?
When cleaning corroded electronics following water damage, extreme caution is required. If you don’t know what you’re doing, you could not only further damage the device, but you could also injure yourself. Remember that devices and liquids do not mix, so be cautious when applying some of these cleaning solutions to a device. The average consumer should never attempt to repair a device without the assistance of a professional. The best rule to remember is: If in doubt, consult a professional! That being said, here are a few helpful hints to remember when dealing with deterioration and water-damaged devices:
● Always remove any batteries, power connectors, or power supplies before cleaning a device that has been exposed to water. This not only keeps you safe, but it also keeps the device from short-circuiting. You will also be exposing extra connectors that may already be corroded if you do this, so proceed with caution.
● Examine the device for any white or green “crusty” areas, particularly on the battery connectors, charging ports, circuit boards, logic boards, SIM card connectors, or any other major metal connectors.
● To clean it, use cotton swabs and a cleaning solution like isopropyl alcohol, baking soda and water, or even vinegar. Apply the solution to the affected area gently and wipe it back and forth until the corrosion is gone. If necessary, apply some of the solutions to the corroded area and then wipe it away.
● Use a soft cloth or a hair dryer on a cool setting to dry out your electronic device; never use heat. Make sure your device is completely dry before attempting to replace the battery and turn it on. Any remaining water in the device may cause additional water damage.
Because corrosion can completely destroy a circuit board, proper cleaning is critical. And, in this guide, we have not only discussed all of the important information about circuit board corrosion, but we have also provided a thorough guide on how to prevent and clean corroded circuit boards. Furthermore, predicting corrosion in PCBs requires experience, and it is often impossible to accurately predict where corrosion will occur until the PCB begins to corrode. Fortunately, corrosion failure does not occur immediately, and there is usually enough time to address the cause effectively.