Variação da composição química da liga Ni-W em função de parâmetros utilizados no processo de eletrodeposição.

Abstract

In this work, Ni-W coatings were manufactured by electrodeposition, following a 2² central composite factorial design with two central points and two axial points, totaling 10 experiments. The design was used to evaluate the influence of electrodeposition parameters (current density and pH) on the chemical composition of the coatings. All samples were characterized in terms of morphology using scanning electron microscopy and X-ray diffraction, and corrosion resistance using potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The results indicated that the coatings obtained were amorphous regardless of the W content, and that, in addition, at low current densities and acidic pH are rich in W (28 to 31 at.%), present microcracks, and are less corrosion-resistant. The coatings obtained at alkaline pH and high current densities have average W contents (11 to 19 at.%), smooth and homogeneous morphology, and are more corrosion-resistant.