Work

The Effects of pH Values on Functional Mechanisms of Nitrite Anions for Q235 Carbon Steels in 0.01 mol L-1 NaNO2-HCl Solutions

Year: 2019

Type: article

Abstract: For Q235 carbon steels in 0.01 mol L -1 NaNO 2 -HCl solutions with different pH values, the effects of pH values on the functional mechanisms of nitrite anions (NO 2 -) were studied.In the pH 1 and pH 2 solutions, the Q235 steels showed the electrochemical behavior of activation, and uniform corrosion (UC) was the main corrosion type on the Q235 surface.The presence of NO 2 -did not affect the electrochemical behavior and the corrosion type but only accelerated the anodic reaction of Fe oxidation.In the pH 3 and pH 4 solutions, the Q235 steels presented the electrochemical behavior of activation-passivation transition, and intergranular corrosion (IGC) occurred on the Q235 surface.The cathodic reaction of NO 2 -reduction resulted in the transition of electrochemical behavior from activation to passivation and the change of corrosion type from UC to IGC.In the pH 5 and pH 6 solutions, the Q235 steels exhibited the electrochemical behavior of self passivation-pitting, and pitting corrosion (PC) was present on the Q235 surface.The strong oxidability of NO 2 -played a critical role in the formation of γ-Fe 2 O 3 passive film on the Q235 surface under the combined action of Fe 2+ and NO 2 -.

Source: Journal of the Brazilian Chemical Society

DOI: 10.21577/0103-5053.20190070

Authors: Yong Zhou, Pei Zhang, Huiju Huang, Jinping Xiong, Fuan Yan

Institutions: Wuhan Institute of Technology, Yulin Normal University, Beijing University of Chemical Technology

Language: English

Topic: Hydrogen embrittlement and corrosion behaviors in metals

Subfield: Metals and Alloys

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $275

Funder: National Natural Science Foundation of China