ISO 20523:2017

Overview

ISO 20523:2017 - Carbon based films - Classification and designations defines a unified system to classify and name carbon based thin films deposited by PVD (physical vapour deposition) or CVD (chemical vapour deposition). The standard covers films where carbon is the predominant constituent - including amorphous carbon (diamond‑like carbon, DLC), polymer‑like carbon, CVD diamond, and graphite films - produced on an industrial scale. It describes what constitutes a single, multilayer or gradient film and clarifies that the standard addresses the film material itself, not an entire multi‑layer coating system. Excluded are carbon nanomaterials such as fullerenes, carbon nanotubes and graphene.

Key topics and technical requirements

• Classification basis: material composition and chemical bonding state (polymer‑like, amorphous, crystalline: diamond or graphite).
• Classification criteria:
  • Crystallinity (non‑crystalline, nanocrystalline 1–500 nm, microcrystalline 0.5–10 µm),
  • Hybridization / bond type (sp, sp2, sp3 ratio - e.g., tetrahedral sp3‑rich films),
  • Hydrogen content (can reach several 10 at.%),
  • Content of additional elements (metallic dopants, non‑metals; metal carbides do not count toward predominant carbon).
• Nomenclature and short names: consistent designations such as a‑C (hydrogen‑free amorphous carbon), ta‑C (tetrahedral a‑C), a‑C:H (hydrogenated), a‑C:Me (metal‑containing), a‑C:H:Me, and modified forms a‑C:H:[X].
• Coating architecture: definitions for monolayer, multilayer, and gradient layers and guidance on when to use each term.
• Supporting information: annexes list common deposition methods and characterization methods for determining the classification criteria.

Applications and practical value

ISO 20523:2017 helps ensure consistent specification, procurement and comparison of carbon based films across industries where surface properties are critical, including:

• Cutting and forming tools, bearings and moving parts (wear and friction control)
• Optics and electronics (protective and functional coatings)
• Medical engineering and microsystems (biocompatible/hard coatings)
• Electrochemical and acoustic components
• Decorative and consumer product finishes

Using the standard streamlines communication between coating suppliers, materials engineers, OEMs, quality managers and R&D teams, enabling reliable selection of the right carbon film (e.g., DLC types, CVD diamond) for specific performance requirements.

Related standards

ISO 20523:2017 was prepared by ISO/TC 107 (Metallic and other inorganic coatings). For specification of deposition or testing procedures, consult applicable ISO or industry standards on PVD/CVD processes and thin‑film characterization that detail measurement methods referenced in the annexes.