Corrosion is a major problem that affects many industries. A lot of money and efforts have been spent to prevent and repair the products from corrosion always spend a lot of money and efforts.
In general, corrosion occurs when a material is oxidized and substance peels off from the surface. Iron rusting is a typical type of corrosion due to oxidation of the iron atoms. This type of damage usually affects metallic materials, and typically produces oxide and/or salt and in turn affect the mechanical, electrical properties of the original metal. Corrosion can also be concentrated locally to form crack and void and it can propagate to a large area to produce deterioration or de-lamination.
Surface detection devices such as
- SEM (scanning electron microscope)/ EDS (Energy Dispersive Spectroscopy)
- XPS (X-ray Photo-electron Spectroscopy )
- AES (Auger Electron Spectroscopy)
are used to observe morphology of metal surface, electric contact interface and analyze compound formation of corrosion products. Metallographic examination is also made to analyze corrosion products and metallurgical structure.
Common Applications
- Plating and Metal Finishing
- Electronics
- Brazing and Soldering
- Castings
Examples
A. Corrosion of galvanized iron
Analysis Technique: Cross-sectioning + Optical Microscope
Figure 1 Optical image of the corroded galvanized iron rim (Objective: 5x)
Figure 2 Optical image of the corroded galvanized iron rim (Objective: 50x)
B. Creeping Corrosion at PWB with IAg finishing
Analysis Technique: SEM/EDX
Figure 3 SEM image of the PWB with immersion silver finishing suffered creeping corrosion (Mag.: 50x)
Figure 4 SEM image of the corrosion product at the corroded PWB (Mag.: 1,000x)
Figure 5 EDX spectrum of the corrosion product at the PWB suffered creeping corrosion. High concentration of S was detected.
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