EMI Shielding Products
- Custom Gasket Fabrication
- Connector Gaskets
- Bonded O Ring
- Custom Gaskets
- Conduct-O-Knit Knitted Wire Mesh
- Conduct-O-Seal Combo Gasket
- Conduct-O-Elastomer
- Conduct-O-Seal Oriented Wire in Silicone Gasket Material
- Conduct-O-Mesh Tape
- Conduct-O-Foam
- Conduct-O-Bond
- Optical Filters For Electronic Displays
- Shielded Vent Panels
- ESC Board Level Shielding
- 300 Series
Understanding EMI Gasket Corrosion
EMI gasket corrosion is a degradation process affecting metals. Metals react chemically or electrochemically with their environment, forming more stable compounds. This process is pertinent to all metals and is a critical concern in electronic packaging. EMI (Electromagnetic Interference) gaskets ensure electromagnetic compatibility by mitigating unwanted electromagnetic emissions.
EMI Gaskets in Electronic Packages
For electronic packages, it's essential to consider the environment they will be exposed to since this influences the potential for corrosion. These environments are broadly classified into four categories.
- Class A (Controlled Environment): This environment is characterized by regulated temperature and humidity, typical of indoor settings where the equipment is protected from harsh external conditions.
- Class B (Uncontrolled Environment): Where there is no control over temperature and humidity, exposing the packages to potentially 100% humidity and occasional wetting. This class includes outdoor environments or uncontrolled storage areas.
- Class C (Marine Environment): This category is specific to locations near salt water, where the saline content significantly increases the risk of corrosion. It encompasses shipboard scenarios or any land exposure within a close range of saltwater that is not covered by Class A conditions.
- Class D (Space Environment): This class involves exposure to the high vacuum and radiation levels found in space, which presents a unique set of challenges for material integrity but is not typically associated with traditional forms of corrosion due to the absence of atmospheric elements.
Given these environmental classifications, the choice of materials and finishes for EMI gaskets and the electronic packages they protect is critical. Metals require specific finishes to mitigate the risk of corrosion, which varies by environment. For example, finishes might range from cadmium plating to chromate conversion coatings, depending on whether the environment is controlled, uncontrolled, marine, or space.
Why Does EMI Gasket Corrosion Matter?
The primary concern with EMI gasket corrosion involves the electrochemical interactions between the gasket material and the metal surfaces it is in contact with, especially in the presence of an electrolyte (moisture being a common one). This interaction can lead to galvanic corrosion, where different metals are electrically connected in a corrosive electrolytic environment, causing the more anodic metal to corrode.
How to Prevent this Problem?
Electronic packages are designed with materials and finishes tailored to their operational environment to address these challenges. This includes selecting appropriate EMI gasket materials that provide the required electromagnetic shielding effectiveness and exhibit compatible electrochemical properties to minimize corrosion potential. Additionally, protective finishes are applied to both the gaskets and the metal surfaces of the package to enhance corrosion resistance, ensuring the longevity and reliability of the electronic systems they encase.