The Influence of Salt Spray on Electronic Devices and Preventative Measures Salt spray is prevalent in marine, atmospheric, terrestrial, lake, and river environments, invariably subjecting electrical and electronic devices to salt-laden atmospheres. Ranking just after temperature, vibration, humidity, and dust in terms of impact, salt spray significantly accelerates the electrochemical corrosion of metals, leading to several issues:
- Corrosion damage to components and fasteners
- Seizing or malfunctioning of mechanical parts
- Circuitry failures such as open circuits or short circuits
The Importance of Salt Spray Testing
To assess the corrosion resistance of products in salt spray environments, salt spray testing has become an essential method. By simulating salt spray conditions, these tests reveal a product’s ability to withstand corrosion. This helps manufacturers enhance product design and material selection to improve reliability and longevity.
The corrosion damage to electronic products in salt spray environments can be attributed mainly to two factors:
- Conductivity of salt solution: Salt solutions are conductive, which triggers and accelerates electrochemical corrosion.
- Increased resistance due to corrosion products: Corrosion products increase resistance, leading to voltage drops and affecting the product’s electrical performance.
Salt Spray Test: Understanding its Impact on Electronic Products and Countermeasures
Salt spray testing is an effective method for evaluating the corrosion resistance of metal materials and their coatings. Common types of salt spray tests include:
- Neutral Salt Spray Test (NSS): Widely used for evaluating the corrosion resistance of metal materials and their metallic or inorganic non-metallic coatings.
- Acetic Acid Salt Spray Test (AASS): Mainly used for testing the corrosion resistance of metal coatings; not suitable for organic coatings.
- Copper Accelerated Acetic Acid Salt Spray Test (CASS): Similar to the acetic acid test but accelerates the corrosion process by introducing copper ions.
Salt spray testing assesses a product’s resistance to salt spray corrosion
The test results reflect surface damage conditions such as:
- Blisters
- Rust
- Decrease in adhesion
- Spread of corrosion at scratch sites
Types and Mechanisms of Salt Spray Corrosion Salt spray corrosion is a common electrochemical phenomenon that primarily affects metal materials and electronic products. Its mechanisms involve anodic activation and cathodic reactions. Different types of corrosion include:
- Surface Corrosion: Uniform material removal from the surface.
- Pitting Corrosion: Localized attacks forming holes or pits deeper than wide.
- Crevice Corrosion: Occurs in narrow crevices where potential differences exacerbate corrosion.
- Dealloying: Selective dissolution common in materials like brass.
- Rust: Formation of iron oxide on iron and steel surfaces.
Salt spray corrosion occurs electrochemically with main mechanisms being:
- Anodic reaction: Metal atoms leave the lattice at the anode, oxidizing and releasing electrons.
- Cathodic reaction: Chloride ions dissociate at the cathode, reacting with metal ions to form corrosion products.
The necessary elements for corrosion are water, oxygen, and ions. While coatings can delay this process, high salt concentrations can penetrate coatings leading to metal corrosion. The specific ability depends on the metal’s electrode potential sequence and environmental pH levels.
Common protective measures against salt spray corrosion include:
- Surface coatings: Applying galvanizing or nickel plating to prevent contact between corrosive mediums and metal surfaces.
- Structural design optimization: Reducing gaps between metal parts and adding sealing structures.
- Material selection: Choosing materials like stainless steel with excellent corrosion resistance.
Conclusion
Salt spray significantly affects metals and electronic devices. Understanding various types of corrosion and their mechanisms is vital for developing effective protective measures. By using resistant coatings, optimizing designs, and selecting suitable materials, products’ ability to endure salt spray environments can be greatly enhanced ensuring long-term reliable operation.
