ISO 15379-2:2015 PDF

Overview

ISO 15379-2:2015 defines a laboratory test method for measuring linear expansion of cathode block materials due to sodium penetration without applied pressure. The standard is aimed at carbonaceous materials used in aluminium production and specifies a controlled electrolysis test in a cryolitic bath to quantify sodium-induced swelling (sodium penetration / sodium-induced expansion). Results help assess material performance and predict risks like block bulging, cracking, and cell relining.

Key topics and technical requirements

• Scope and purpose: Determines maximum relative linear expansion (%) caused by sodium penetration when no external pressure is applied. Notes that expansion is anisotropic and depends on sampling direction.
• Sample geometry and sampling: Sample diameter (30.0 ± 0.1) mm, length 100 mm; central drilled hole 6 mm ∅ threaded to (25 ± 5) mm; sampling per ISO 8007-1 and orientation must be reported.
• Test bath and temperature: Cryolitic bath with a cryolite ratio of 4.0 (composition detailed in the standard), total bath mass 765 g; furnace maintained at (980 ± 5) °C with