PCB Corrosion: Causes and Prevention Methods

 

PCB corrosion is caused by many different factors, such as Atmospheric Corrosion, Localized Corrosion, Electric Corrosion, Electrolytic Corrosion, Electrolytic Dendrite Formation, Fretting Corrosion and Intergranular Corrosion.

 

Corrosion can be extremely harmful to PCBs. Although there are many reasons that can cause PCB corrosion, there are several ways to clean it with traditional household products such as baking soda and compressed air. We can also take preventive measures to ensure that PCB corrosion will not occur in the future.

 

What Causes PCB Corrosion?

 

Corrosion of the circuit board can completely destroy the PCB, rendering it useless. There are many reasons for this corrosion, which is the oxidation process that occurs when oxygen combines with metal to produce rust and peeling.

 

Atmospheric Corrosion

 

Atmospheric corrosion is the most common type of PCB corrosion. The metal on the PCB is exposed to moisture, which in turn exposes it to oxygen. The combination of these elements results in a reaction where metal ions bond with oxygen atoms to form oxides. Atmospheric corrosion mainly occurs on copper components. Although copper retains its mechanical properties even if it is corroded, it does not retain its electrical conductivity.

 

Localized Corrosion

 

Localized corrosion is similar to any type of general corrosion. The difference is that it mainly affects a limited area or a smaller area. Such corrosion can include filiform corrosion, crevice corrosion and pitting corrosion.

 

Electric Corrosion

 

This type of corrosion occurs at the location of various metals and electrolytes where the corrosion-resistant metal corrodes faster than the base metal it contacts.

 

Electrolytic Corrosion

 

Electrolytic corrosion occurs when the contact marks cause dendrites to grow. This growth occurs when contaminated ionic moisture enters the voltage between the two traces. The result is that the metal strip causes a short circuit.

 

Electrolytic Dendrite Formation

 

When there is ion contamination in the water, electrolytic dendrite formation occurs. This deformation will cause any adjacent copper traces with different voltages to grow metal strips, which will eventually cause a short circuit between the traces.

 

Fretting Corrosion

 

The fretting is the result of continuously closing the tinned switch. This movement produces a wiping action, which finally removes the surface oxide layer. When this happens, the underlying layer will oxidize and form excessive rust, which hinders the operation of the switch.

 

How to Remove Corrosion on PCB?

 

With the passage of time, after your PCB is corroded, dirt, dust and all kinds of dirt can easily enter your electronic equipment. If you detect that the PCB has been corroded, you can learn how to remove the corrosion and use the following methods to avoid permanent damage.

 

Use Compressed Air

 

Compressed air is a fairly common tool for electronic cleaning. You can use compressed air by releasing short pulses into the inside of the vent. It is recommended to use this cleaning method for routine electronic care.

 

Use Baking Soda

 

Baking soda is an effective ingredient for removing PCB corrosion. Since baking soda is moderately abrasive, you can use it to scrub away corrosion and residue that will not be released by compressed air.

 

Use Household Cleaners

 

Any household cleaner is a good way to solve PCB corrosion, but the premise is that it must be phosphate-free. There are also special PCB corrosion cleaners on the market.

 

Use Brush

 

When you clean the circuit board, the brush can be a super useful tool because it can help you get in between all the tiny components. It is important to choose a brush with soft bristles. Size is also important because you need to be able to reach all the smallest spaces. Most people like to use a toothbrush or paint brush. They are strong and gentle, most people already have at least one of them. A lint-free microfiber cloth is also a good tool to wipe and dry the circuit board immediately after cleaning.

 

How Do You Prevent Corrosion on the Circuit Board?

 

Different metals have different levels of corrosion risk. Although they may eventually corrode, copper and other base metals corrode much easier and faster than precious metals and certain alloys. The latter is more expensive, so many professionals will stick to the more common metals, so it is necessary to know how to prevent PCB corrosion without damaging its circuit boards.

 

An easy way to prevent corrosion on the circuit board is to place a coating on the exposed copper area. There are many different types of coatings, including epoxy coatings, aerosol spray coatings and solder resists. You should also try to avoid moisture around the PCB.

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