Prpogation Mechanism of Microcracks Caused by Corrosion of Laser Cladded In625 Coating on Nodular Cast Iron in 3.5％NaCl Solution
IN625 coating was laser clad on the surface of QT600 nodular cast iron,and the micro-structure and composition of the clad coating were characterized by means of optical microscope and scanning electron microscope with energy dispersive spectroscope.The electrochemical corrosion behav-ior of the IN625 clad QT600 nodular cast iron was examined in 3.5％NaCl solution.Meanwhile,a numeri-cal model of the transient evolution of micro-crack growth induced by corrosion of IN625 laser cladding layer was established,considering the corrosion process induced by the existence of micro-cracks in the cladding layer working in a harsh environment.The transient evolution of ion concentration,ion migration,pH value,electrode potential and corrosion rate during corrosion were analyzed.The results show that the corrosion resistance of IN625 clad QT600 nodular cast iron is significantly superior to that of the bare QT600 nodular cast iron.
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