Overview
ISO 23486:2021 specifies a standardized method to measure the in‑plane Young’s modulus of thermal barrier coatings (TBCs) formed on metallic substrates using the flexural resonance method at temperatures from room temperature up to 1 000 °C. The standard is intended for multilayer TBC systems consisting of a metallic bond coat (BC) and a ceramic top coat (TC) applied to heat‑resistant metallic substrates (e.g., nickel or cobalt‑based superalloys).
Key topics and technical requirements
- Measurement principle: Determination of Young’s modulus by measuring the flexural resonance frequency of three specimen types - the substrate, substrate+BC and substrate+BC+TC - at the test temperature and applying composite beam vibration theory.
- Temperature range: Measurements and pre‑conditioning up to 1 000 °C; specimens are recommended to be preheated at the maximum test temperature for about 2 hours to stabilize microstructure and mechanical response.
- Apparatus: A flexural resonance system combined with a controlled heating device (furnace). Suspension by a heat‑resistant thread (e.g., alumina yarn) is specified to permit free vibration.
- Specimen geometry and tolerances: Beam specimens with defined length, width and thickness ranges (e.g., substrate thickness 1.5–2.5 mm; width ≥ 5.0 mm with limits relative to length). Coating thickness bounds and ratios for BC and TC are specified to ensure valid calculations.
- Measurement procedure: Precise dimension and mass measurements (referencing ISO 13385, ISO 3611, ISO 1463) followed by resonance frequency measurement at stabilized temperatures.
- Calculations: Young’s moduli for the substrate, BC and TC are calculated from measured resonance frequencies, dimensions and masses using the formulas provided; results are reported per clause 9.
- Reporting requirements: Test report must include materials, spraying conditions, specimen dimensions and masses, preheat and test temperature conditions, resonance frequencies, computed Young’s moduli, deviations and date of measurement.
Applications and users
ISO 23486 is practical for:
- Coating laboratories performing mechanical characterization of TBC systems
- Gas‑turbine and aero‑engine manufacturers validating coating performance at high temperatures
- Materials engineers and researchers studying thermal protection systems and high‑temperature modulus changes
- Quality control and certification bodies assessing TBC mechanical properties for lifecycle prediction
Typical use cases: high‑temperature property verification of thermal barrier coatings for power‑generation turbines, hot‑section components testing, research on coating degradation and design of multilayer TBC systems.
Related standards
Keywords: ISO 23486:2021, thermal barrier coatings, Young’s modulus, flexural resonance method, elevated temperature testing, TBC measurement, bond coat, top coat, high‑temperature mechanical properties.
Open preview (PDF)Metallic and other inorganic coatings — Measurement of Young’s modulus of thermal barrier coatings at elevated temperature by flexural resonance method
