ISO 23331:2021 PDF

Overview

ISO 23331:2021 specifies a standardized test method for the total electrical conductivity of conductive fine ceramics using the DC four‑terminal method. The procedure applies to conductive fine ceramics whose ionic transference number is 0.01 or less, over a conductivity range of 1 S·cm⁻¹ to 1 000 S·cm⁻¹ and temperatures up to 1 000 °C. Values are reported in SI units. The standard is targeted at industrial product quality control and material development for conductive ceramics used as electrodes in fuel cells, batteries and water electrolysis.

Key topics and technical requirements

• Measurement principle: DC four‑terminal method - four wire electrodes are wrapped on the test piece; the outer electrodes supply current and the inner electrodes measure voltage (minimizes contact resistance).
• Applicability limits: Ionic transference number ≤ 0.01; conductivity 1–1 000 S·cm⁻¹; temperature up to 1 000 °C.
• Test specimen: Typical dimensions ~4 × 3 × 35–40 mm (minimum length 20 mm when necessary); bulk density measured per ISO 18754; surface roughness