An Investigation of Primary Circuit Materials in Molten Chloride Salts with the Design of High Temperature Corrosion Vessels

  • Craig Jantzen

Student thesis: Phd


To pursue high temperature chloride salt corrosion experiments, experimental equipment and corrosion vessels were designed, manufactured and tested. During the project, vessels were developed with success in producing stable, inert environments to enable the corrosion tests to be carried out. Undergoing continual development, separate vessels were produced for the different temperature ranges, with lessons learnt being applied to produce simplified and increasingly effective corrosion vessels. Static corrosion tests were carried out to determine the corrosion rates, mechanisms, and compatibility for candidate high-temperature materials for use in LiCl-KCl (59.5:40.5 mol%) and KCl-MgCl2 (68:32 mol%) eutectic salts. Several high temperature alloys including; Hastelloy-N, Haynes-214, Haynes HR-224, Molybdenum and TZM were exposed to both salts under a variety of conditions and temperatures. These range from in air (in alumina crucibles) and argon (in nickel crucibles) environments, durations ranging from 125 to 500 hrs, and temperatures of 600°C and 850°C. The corrosion of the nickel alloys occurred primarily from the de-alloying of the Cr from the surface of the materials. This could either occur as a uniform attack, more common in the 600°C tests, or as intergranular, seen more commonly in the 850°C tests. Alloy mass-loss correlated with the initial Cr content in the alloys, with a higher rate of loss with increasing Cr. LiCl-KCl was consistently found to be most aggressive salt over the range of temperatures and conditions tested. The higher Cr containing alloys showed intergranular attack, which penetrated the bulk of the surface much more rapidly than seen in the low Cr alloy Hastelloy-N. This was particularly prominent at the 850°C test, with increasing Cr diffusion rates and the formation of CrC at the grain boundaries vastly accelerating the corrosion attack. Molybdenum and TZM as expected, saw very little corrosion nickel crucibles acted as a cathodic shield, and a protective Ni plating was formed at the materials surface.
Date of Award1 Aug 2019
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorDirk Engelberg (Supervisor) & Timothy Abram (Supervisor)


  • Molybdenum
  • Haynes
  • LiCl-KCl
  • Nuclear
  • Hastelloy-N
  • KCl-MgCl2
  • Vessel
  • Chlorides
  • High Temperature
  • Nickel Alloy
  • Corrosion
  • Molten Salt

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