Corrosion resistance of electrodeposited nanomaterials

The corrosion behavior of NC alloys has been assessed by several techniques in various environments. Corrosion behaviors of two types of NC Cu-Ni alloys (details on alloys in Table 5.2) were compared with cast Monel-400 alloy in 3% NaCl solution and it was found that corrosion current density (i ) of NC alloys was superior to Monel-400 (Fig. 5.11 and Table 5.6). Both optical and SEM examination of the corroded snrface revealed a well-defined pitting type of attack for Monel-400, unlike the homogeneous corrosion of NC alloys. Thorpe etal. (1988)reportedanenhancedcorrosionresistanceofNCFe32Ni36Crl4P12B6 compared with that of its amorphous counterpart. The authors attributed this improved corrosion resistance to the observed greater Cr enrichment of the 

11 Potentiodynamic polarization plot of nanocrystalline and conventional Ni-Cu alloys in 3% NaCI solution (Ghosh etal., 2006). 

Nanociystalline alloy coatings, oxide dispersive alloy coatings and metal oxide composite coatings show superior high temperature corrosion resistance. A Ni-Cr nanocomposite with an average Cr concentration of 11 wt% deposited onto nickel 

12 Corrosion rate with immersion time for pure zinc coating and composite coating samples in 3.5% NaCI solution (Praveen and Venkatesha, 2009). 

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