J. Mater. Sci. Technol. ›› 2018, Vol. 34 ›› Issue (3): 561-569.DOI: 10.1016/j.jmst.2016.11.001

Special Issue: Corrosion in 2018

• Orginal Article • Previous Articles     Next Articles

Characteristics of Oxidation and Oxygen Penetration of Alloy 690 in 600 °C Aerated Supercritical Water

Xiangyu Zhong(), Xinqiang Wu(), En-Hou Han   

  1. CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
  • Received:2016-06-17 Revised:2016-09-22 Accepted:2016-10-14 Online:2018-03-20 Published:2018-03-20

Abstract:

The oxide films formed on Alloy 690 exposed to 600 °C supercritical water were characterized using mass measurement, X-ray diffraction, Raman spectroscopy, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. It was found that the mass gain of the alloy in supercritical water decreased with increasing exposure time. The oxide films have a double-layer structure, with an inner layer rich in Cr and outer layer rich in Ni and Fe after short time and long time exposure. The penetration of the oxide along the grain boundaries was observed, and the penetration depth increased with increasing exposure time. The grain boundaries and voids are the short-path of oxygen diffusion into the metal.

Key words: Ni-based alloy, XPS, Supercritical water, High temperature corrosion, High temperature oxidation, Oxide film