Corrosion Behavior in Boiling Dilute HCI Solution of Different Ceramic Coatings Fabricated by Plasma Spraying

摘要

An Al{sub}2O{sub}3 ceramic coating (A), a 13 wt.% TiO{sub}2-Al{sub}2O{sub}3 (13TA) composite ceramic coating, and a Ni-Al-13wt.%TiO{sub}2-Al{sub}2O{sub}3 (NA-13TA) gradient composite ceramic coating were prepared on Q235 steel by plasma spraying. The corrosion behavior of samples sprayed with these coatings in a boiling 5% HCl solution was investigated. It was shown that an A ceramic coating and a 13TA composite ceramic coating were destroyed after immersion for 17 and 23 h, respectively. The NA-13TA gradient composite ceramic coating was still sound after 14 days of immersion. The corrosion resistance of samples with the NA-13TA gradient composite ceramic coating was sharply improved due to the decreased amount of connected pores in the coating. The corrosion of the sample sprayed with the gradient ceramic coating included the partial corrosion of the surface ceramic coating and the interlayer coatings. The corrosion weight loss depended on the degree of open porosity.