Resumo

GADHARI, Prasanna  e  SAHOO, Prasanta. Effect of Heat Treatment and Bath Process Parameters on the Corrosion Behavior of Ni-P-TiO2 Composite Coatings. Port. Electrochim. Acta [online]. 2015, vol.33, n.3, pp.165-181. ISSN 0872-1904.  https://doi.org/10.4152/pea.201503181.

The present research article deals with the study of corrosion behavior of Ni-P-TiO2 composite coating. The TiO2 composite coating is deposited on the mild steel substrate. Corrosion behavior of the TiO2 composite coatings after heat treatment at various annealing temperatures (300 °C, 400 °C, and 500 °C) is evaluated with the help of potentiodynamic polarization test using 3.5% NaCl solution. The electrochemical parameters, corrosion potential (E_corr) and corrosion current density (I_corr), are optimized for maximum corrosion resistance using Taguchi based grey relational analysis. The coating parameters, namely, nickel sulphate, sodium hypophosphite, concentration of TiO2 particles and annealing temperature are considered as main design factors. The analysis of variance (ANOVA) revealed that the annealing temperature and concentration of TiO2 particles have significant influence on the corrosion behavior of the composite coating. The microstructure characterization of the coating is conducted using scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction analysis. The Ni-P-TiO2 composite coating exhibits nodular structure with uniform incorporation of titanium particles and converts into the crystalline structure after heat treatment.

Palavras-chave : Ni-P-TiO2 composite coating; corrosion; potentiodynamic polarization; optimization.

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