Overview
ISO 13123:2011 specifies a laboratory test method of cyclic heating for thermal-barrier coatings (TBCs) under a temperature gradient. It is intended to evaluate the thermal‑barrier performance and cyclic heat resistance of coatings used on high‑temperature components (burners, rotor/stator blades, combustor liners) in power‑generation gas turbines, aircraft engines and rocket engines. The standard defines the test principle, specimen geometry, required equipment, measurement methods and evaluation criteria for cyclic thermal loading under a controlled temperature gradient.
Key topics and technical requirements
- Test principle: apply repeated heating/cooling cycles to a coated test piece while measuring temperature distribution, heat flux or acoustic emissions to assess insulation performance and damage development.
- Test piece: typical specimen is a disk (diameter 15–30 mm). Edges of the heated surface should be rounded (≈0.5–2 mm) or chamfered to reduce edge cracking. Coating thickness must be measured at multiple points and kept within ±10% of the average.
- Equipment components:
- Heating unit: burner, plasma, IR lamp, laser, e‑beam, etc., with shutter or motion to create cyclic heating.
- Cooling unit: coolant (air, water…) to maintain a temperature gradient across the substrate.
- Test block: includes the test piece, optional heat flux meter (brazed or directly coated), and holder.
- Controller: to reproduce temperature gradient and cycle timing reliably.
- Measuring instruments: thermocouples (IEC 60584), radiation pyrometer for surface temperature, cameras for visual inspection, and optional acoustic emission (AE) sensors for damage detection. AE transducer spec: 100 Hz–1 MHz; preamp ≥40 dB; main amp ≥25 dB.
- Chamber: when testing in controlled atmospheres (e.g., reducing).
- Measurements & evaluation:
- Track temperature histories and confirm heating rates and gradient.
- Determine equivalent effective thermal conductivity or monitor AE event frequency.
- Visually inspect and quantify spalling area ratio and count cycles to damage tolerance limit.
- Annex provides calculation guidance (e.g., temperature at bottom of top coat).
Applications and users
ISO 13123:2011 is used by:
- Coating manufacturers for product development and quality control.
- Turbine and engine OEMs for supplier qualification and component validation.
- Independent test laboratories for comparative testing and certification.
- R&D teams and materials scientists studying TBC lifing, failure modes, and thermal performance under realistic gradients.
Practical benefits include informed TBC selection, lifetime estimation, failure analysis and standardized comparison of cyclic heat resistance.
Related standards
Normative references include ISO 1463, ISO 2063, ISO 2178, ISO 14917, ISO 80000‑1 and IEC 60584 (thermocouples). These provide complementary methods for coating thickness measurement, thermal‑spray terminology and temperature sensing.