Metal corrosion significantly affects material performance and service life. SEM can observe the micromorphology of corrosion areas, including general corrosion, pitting, crevice corrosion, intergranular corrosion, exfoliation corrosion, and stress corrosion cracking. SE imaging reveals pit morphology, depth, density, corrosion product coverage, and crack initiation/propagation. BSE imaging helps distinguish compositional differences between corrosion products and the metal matrix. Corrosion products often appear loose, porous, cracked, layered, or granular; high depth-of-field imaging displays their three-dimensional structure. EDS determines elemental composition and distribution, indicating enrichment of oxides, chlorides, sulfides, and carbonates and the presence of corrosive elements. Cross-sectional analysis can reveal corrosion layer thickness, layered structure, and the interface between the corrosion front and matrix, helping evaluate corrosion severity, corrosion resistance, and the effectiveness of protective measures.
