Acta Metallurgica Sinica (English Letters) ›› 2019, Vol. 32 ›› Issue (1): 89-97.DOI: 10.1007/s40195-018-0821-6

Special Issue: 2019年腐蚀专辑-1

• Orginal Article • Previous Articles     Next Articles

Effects of Lead on the Initial Corrosion Behavior of 316LN Stainless Steel in High-Temperature Alkaline Solution

Jia-Min Shao1, Cui-Wei Du1(), Xin Zhang2(), Li-Ying Cui1   

  1. 1. Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China
    2.Nuclear and Radiation Safety Center, Ministry of Environmental Protection of P. R. China, Beijing 100082, China
  • Received:2018-04-18 Revised:2018-08-04 Online:2019-01-10 Published:2019-01-18
  • Contact: Du Cui-Wei,Zhang Xin
  • About author:

    Author brief introduction:Dao-Kui Xu Professor of IMR, CAS, and “Young Merit Scholar” of Corrosion Center in the Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS). He achieved Ph.D. degree from IMR, CAS, in 2008, during which he obtained “Chinese Academy of Sciences-BHP Billiton” Scholarship award, “Shi Changxu” Scholarship award and “Zhu-LiYueHua” Excellent Doctorate Student Scholarship of Chinese Academy of Sciences. He worked as a Research Fellow in ARC Center of Excellence, Design of Light Metals, Department of Materials Engineering, Monash University, Australia (2008.10-2011.10). He published more than 60 peer-reviewed scientific papers, attended 20 invited lectures and holds seven patents. His papers were cited more than 1200 times. His research interests mainly include: (1) fatigue behavior and fracture toughness of light metals, such as Mg, Al and Ti alloys; (2) effects of alloying, heat treatment and thermomechanical processes on the microstructural evolution and mechanical improvement of light metals; (3) corrosion, stress corrosion cracking and corrosion fatigue behavior of lightweight alloys; and (4) design of new lightweight alloys with a good balance of properties in terms of mechanical property and corrosion resistance.

Abstract:

The effect of lead on the initial corrosion behavior of 316LN stainless steel has been investigated by U-bend immersion experiments in 4 wt% NaOH solutions at 300 °C. Follow-up studies after soaking were carried out by scanning electron microscope, energy dispersive X-ray spectrometer, X-ray photoelectron spectrometer, Auger electron spectroscopy and Raman spectroscopy. The results show that lead affects the properties of the oxide film by changing the thickness and composition, which leads to an increase in the sensitivity of stress corrosion cracking of 316LN stainless steel. Pits and cracks appeared on the surface of 316LN stainless steel under both lead-free and lead-containing conditions. The corrosion products were oxides of Fe, Cr and Ni, and the main spinel structure on the surface of the film was NiCr2O4 under both conditions. However, in the presence of lead, the cracks and pits were more obvious, the thickness of the film increased from 50 to 200 nm, and the amount of protective NiCr2O4 decreased. Lead was concluded to be involved in the dehydration reactions in the form of Pb(OH)2, which affected the normal dehydration process of the hydroxides and inhibited the formation of spinel structures. Because of the above characteristics of lead, the stability of the oxide film and its protection of 316LN stainless steel were reduced.

Key words: PbSCC, Oxide film, 316LN, High temperature