Corrosion of Ni-Al and Ni-Al-Al₂O₃ Flame Sprayed Coatings of „CastoDyn 8000" System in 0.01 M H₂SO₄ and 3.5% NaCl Solutions

Abstract:

In the paper researches results of corrosion properties of Ni-Al alloy and Ni-Al-Al₂O₃ composite coatings were presented. Coatings were obtained by flame spraying of "Casto-Dyn 8000" torch. During coatings flame spraying of torch was used a small distance from the substrate. Instead of commonly used spray distance 150 mm, 100 mm was used. The studies in 0.01 M H₂SO₄ and 3.5% NaCl (artificial seawater) environments were realized. Evaluated coatings are more corrosion resistant in the 3.5% NaCl environment than in the 0.01 M H₂SO₄. Corrosion current density for alloy coatings in artificial seawater was 20 μA/cm² and 223 μA/cm² in an acidic environment. The value of corrosion potential in an environment of 3.5% NaCl is about 200 mV lower than in 0.01 M H₂SO₄. Composite coatings Ni-Al-Al₂O₃ were characterized by a lower corrosion current densities and increased resistance than Ni-Al coatings in acidic environment. The presence of alumina in the coating matrix caused increased corrosion current density in sea water environment.

• Periodical: Solid State Phenomena (Volume 183)
• Pages: 185-192
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.183.185
• Online since: December 2011
• Authors: Robert Starosta
• Keywords: Composite Coating, Corrosion, Short Spraying Distance, Thermal Spray Coating

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