ISO 18755:2022 PDF

Overview

ISO 18755:2022 specifies the standardized test method for determining thermal diffusivity of monolithic fine ceramics (advanced/technical ceramics) using the flash method (e.g., laser flash). The standard covers measurements from room temperature to at least 1 700 K for homogeneous monolithic ceramics with porosity < 10 %. Flash methods are applicable to isotropic materials with thermal diffusivity in the range 0.1 to 1 000 mm2·s‑1 and broadly across temperatures from ≈100 K up to ≈2 300 K. Annex G describes how to estimate specific heat capacity and thermal conductivity from the measured thermal diffusivity.

Key technical topics and requirements

• Scope and specimen limits: Homogeneous monolithic ceramics, porosity < 10 %; specimen geometry and density requirements are defined (see ISO 18755 for specifics).
• Flash source: Pulse laser, flash lamp or equivalent capable of a short, high‑energy pulse; pulse duration preferably < 1.0 ms (FWHM) with uniform irradiation of the front face.
• Detection and timing: Rear-face transient temperature is recorded with a non-contact radiation thermometer or detector. Detector and electronics should have a frequency response > 10 kHz. Target detector area must be