Impedance spectroscopy studies of electroless Ni–P matrix, Ni–W–P, Ni–P–ZrO2, and Ni–W–P–ZrO2 coatings exposed to 3.5% NaCl solution. Issue 10 (5th November 2012)

• Record Type: Journal Article
• Authors: Stankiewicz, A.; Masalski, J.; Szczygieł, B.
• Is Part Of: Materials and corrosion. Volume 64:Issue 10(2013:Oct.)
• Page Start: 908
• Page End: 913
• Publication Date: 2012-11-05
• Subjects: Materials -- Periodicals; Metals -- Periodicals; Corrosion and anti-corrosives -- Periodicals; 620.1122305
• DOI: 10.1002/maco.201206856
• Languages: English
• ISSNs: 0947-5117

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Ni–P matrix, ternary Ni–W–P and Ni–P–ZrO₂ coatings, and quaternary Ni–W–P–ZrO₂ coatings were deposited using electroless method from a glycine bath. Their corrosion resistance was evaluated by electrochemical impedance spectroscopy (EIS) for various immersion times in a 3.5% NaCl solution. From among the investigated coatings, the ternary Ni–W–P coatings show the highest resistance to corrosion in the first hour of exposure to the 3.5% NaCl medium. An addition of ZrO₂ adversely affects the performance of both the Ni–P coatings and the Ni–W–P coatings. For all the coatings, including the ones containing tungsten, a marked decrease in pore resistance (R_por) over time is observed. This means that their corrosion resistance and capacity to protect the substrate decline. On the other hand, after 24 h immersion in the 3.5% NaCl solution the Ni–W–P coating shows the highest low‐frequency impedance modulus (|<italic>Z</italic>|_{f = 0.01 Hz}). As regards corrosion resistance, the Ni–P coatings and the Ni–W–P coatings perform best.</p> </abstract>