Development of wide-range viscometer and the viscosity measurement for SiO2–Na2O–NaF system

Osamu Takeda, Masaya Yamada, Masane Kawasaki, Mayu Yamamoto, So Sakurai, Xin Lu, Hongmin Zhu

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


A rotating crucible viscometer previously developed by the authors was improved in order to measure wide-range of viscosity values with high reliability. Two sets of inner cylinder and crucible with different geometries were employed as an attempt to accomplish this objective. The centers of these components were matched with accuracy of ± 0.1 mm by adopting X-Y stage for positioning. Relative error in torque measurement was less than 1.5%, and calibration curves had a good consistency for all experiments. By using the improved viscometer, a typical molten salt, LiF–10 mol% NaF–45 mol% KF (FLiNaK), a high-temperature low viscosity liquid, was measured and the results agreed with the theoretical values estimated from pure substances relations. Viscosity of the SiO2–Na2O–NaF system (CNa2O /CSiO2 = 0.67 in mol%) was obtained by varying concentration range from 0 to 80 mol% NaF. All melts’ composition tested followed Arrhenius-type temperature dependence, and a viscosity relation at 1 473 K based on composition was also obtained. Drastic decreases in activation energy for viscous flow were observed at the concentrations of 5 and 80 mol% NaF.

Original languageEnglish
Pages (from-to)590-596
Number of pages7
JournalIsij International
Issue number3
Publication statusPublished - 2020


  • ESR slag
  • LiF–NaF–KF
  • Mold flux
  • Oxyfluoride melt
  • Rotating crucible method
  • SiO–NaO–NaF
  • Viscosity

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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