J. Mater. Sci. Technol. ›› 2018, Vol. 34 ›› Issue (10): 1781-1790.DOI: 10.1016/j.jmst.2018.03.021

• Orginal Article • Previous Articles     Next Articles

Effect of nitrogen on corrosion behaviour of a novel high nitrogen medium-entropy alloy CrCoNiN manufactured by pressurized metallurgy

Hao Fenga, Huabing Lia(), Xiaolei Wub(), Zhouhua Jianga, Si Zhaoa, Tao Zhangc, Dake Xuc, Shucai Zhanga, Hongchun Zhua, Binbin Zhanga, Muxin Yangb   

  1. aSchool of Metallurgy, Northeastern University, Shenyang 110819, China
    bState Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
    cSchool of Materials Science and Engineering, Northeastern University, Shenyang 110819, China
  • Received:2017-12-28 Revised:2018-01-31 Accepted:2018-03-06 Online:2018-10-05 Published:2018-11-01

Abstract:

A novel high nitrogen medium-entropy alloy CrCoNiN, which had higher strength and slightly lower ductility than CrCoNi alloy, was successfully manufactured by pressurized metallurgy. The microstructure and corrosion behaviour were investigated by microscopic, electrochemical and spectroscopic methods. The results indicated that nitrogen existed in the form of Cr2N precipitates and uniformly distributed N atoms, and nitrogen alloying significantly refined the grain size. Besides, nitrogen enriched on the outmost surface of passive film and metal/film interface as ammonia (NH3 and NH4+) and CrN, respectively. The significant improvement of corrosion resistance of CrCoNiN was attributed to the lower metastable pitting susceptibility together with thicker, less defective and more compact passive film.

Key words: Medium-entropy alloy, Nitrogen, Pitting corrosion, Passive film, Metastable pitting