Time-dependent corrosion behavior of electroless Ni–P coating in H2S/Cl− environment. (23rd March 2021)

• Record Type: Journal Article
• Authors: Li, Longyi; Wang, Jun; Xiao, Jie; Yan, Jing; Fan, Hongyuan; Sun, Lan; Xue, Ling; Tang, Zhenghua
• Is Part Of: International journal of hydrogen energy. Volume 46:Number 21(2021)
• Page Start: 11849
• Page End: 11864
• Publication Date: 2021-03-23
• Subjects: Ni–P coating -- Corrosion -- H2S -- Pipeline steel; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2021.01.053
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: As a mature technology, electroless Ni–P alloy coating is widely applied in the protection of chemical equipment and pipelines owing to its excellent corrosion resistance, but its application and long-term service evaluation in the field of high-sulfur oil and gas are rare. Therefore, the time-dependent corrosion behavior of Ni–P coating, which was plated on the L360 steel surface, was investigated in a saturated H2 S medium by the method of surface analysis. The results indicate that Ni–P coating with a thickness of about 52.6 μm could significantly reduce the corrosion rate compared with uncoated pipeline steel. This is related to the structure of the dense, protective film on the surface. The uncoated pipeline steel suffered local corrosion during the immersion process, and then it developed into uniform corrosion with the formation of a large number of corrosion products. In comparison, Ni–P coatings corroded relatively mildly with only a thin corroded layer. However, during prolonged corrosion testing, the corrosive medium penetrated the coating/substrate interface at inherent defects, leading to severe local corrosion of the substrate. Highlights: Corrosion behavior of electroless Ni–P coating in saturated H2 S solution was evaluated during long-term immersion. The types of corrosion products formed on Ni–P coating were analyzed at various times. Ni–P coating can resist H2 S attack for a short time. After long-term immersion, the failure of the coating is related to its inherent defects.