Classification of corrosion defects in NiAl bronze through image analysis

Corrosion surface damage in the form of pitting and micro-cracks is observed in many metals. Cracks usually initiate from the pits and grow under cyclic stresses and eventually lead to material failure. An image analysis based on wavelet transforms and fractals was used to study the corrosion morphology of nickel aluminum bronze metal under varying corrosion conditions and applied stresses. Image feature parameters were extracted and analyzed to classify the pits/cracks in the metal samples. The results obtained indicate that classification of pits/cracks is possible with image analysis and may be used for correlating service/failure conditions based on corrosion morphology.

Research highlights
► Image analysis based approach can classify defects in NiAl bronze metal subjected to corrosion and cyclic stresses.
► Fractal dimension can classify pits/cracks in NiAl bronze specimens.
► Pits/cracks are linearly separable based on the fractal dimension and entropy features.