Overview
ISO 5154:2023 - "Decorative metallic coatings for radio wave transmissive application products - Designation and characterization method" - defines how to describe and measure decorative metallic coatings that must both transmit radio waves and retain a metallic appearance. It standardizes a designation system (symbol, frequency band, transmission loss, lightness, hue, main element, manufacturing method) and prescribes characterization methods for radio‑wave transmission loss and color/appearance.
Key topics and requirements
- Designation format: A structured code beginning with the elementary symbol StM, followed by:
- a frequency‑band letter (band classification),
- T + transmission loss (dB) rounded to one decimal,
- L + lightness (integer),
- hue code,
- main elemental symbol, and
- manufacturing method code (Ve = vacuum evaporation, Sp = sputtering, Ep = electro/electroless plating, OP = other).
- Example: StM D T0,4 / L90 BG / Cr / Sp (W‑band, 0.4 dB loss, lightness 90, blue‑green hue, Cr main element, sputtering).
- Transmission loss measurement: Determined in accordance with IEC 62431 (measurement methods for millimetre‑wave reflectivity/attenuation). Results are reported for the relevant frequency band and rounded as specified.
- Colour and appearance: Lightness (L*), chroma (C*), a*, b*, and hue angle are specified per ISO/CIE 11664‑4 (CIELAB). Colour names follow Munsell conventions (JIS Z 8721 / ASTM D1535) for samples with sufficient chroma; achromatic for low chroma (C* ≤ 0.8).
- Sampling and conformity: Sampling follows ISO 4519 and samples must replicate production materials and coating configurations.
- Support information: Annex A and B provide informative measurement examples for transmission loss and colour.
Practical applications
- Automotive exterior decorative parts (e.g., metallized plastic emblems) that sit in front of millimetre‑wave radar sensors for ADAS/collision prevention.
- Consumer electronics and housings requiring metallic finish without blocking wireless signals (radar, Wi‑Fi, 5G/mmWave).
- Coating suppliers and process engineers designing discontinuous metallic films (e.g., low‑melting‑point metal islands) to balance metallic appearance and low radio attenuation.
- Test laboratories specifying measurement protocols and product acceptance criteria.
Who should use this standard
- Automotive OEMs and tier‑1 suppliers
- Coating manufacturers (PVD, sputtering, vacuum evaporation, plating)
- EMC and RF test labs
- Product designers integrating radar‑transparent decorative elements
- Quality and compliance teams specifying acceptance criteria
Related standards
- ISO/CIE 11664‑4 - CIELAB colorimetry
- IEC 62431 - Millimetre‑wave transmission/reflectivity measurement
- ISO 4519 - Sampling procedures for metallic coatings
- ISO 2080 - Coatings vocabulary
Keywords: ISO 5154:2023, decorative metallic coatings, radio wave transmissive, transmission loss measurement, CIELAB, frequency band designation, sputtering, vacuum evaporation, automotive radar, metallized emblems.
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