Overview
ISO 14924:2005 - Thermal spraying: Post-treatment and finishing of thermally sprayed coatings defines recommended methods for treating and finishing thermally sprayed coatings. The standard covers mechanical, chemical and thermal post-treatments required to achieve required surface quality, function and durability of coatings produced by thermal spraying. It emphasizes the special lamellar structure and mixed hard phases of sprayed layers and gives practical guidance for avoiding damage during finishing.
Key topics and requirements
- Scope of treatments: Mechanical (chip cutting, turning, milling, grinding, belt finishing, drilling, sawing), chemical (sealing, chemical conversion, painting) and thermal (fusing, diffusion annealing, hot isostatic pressing).
- Mechanical post-treatment:
- Tool selection and geometry must account for embedded hard phases (oxides, carbides, etc.). Hard metals, carbide or CBN tools are recommended for high-hardness coatings (CBN for coatings > ~700 HV).
- Cutting speeds and feeds are typically lower than for homogeneous materials; test cuts are recommended.
- Grinding: wet grinding is preferred to limit overheating; sealing prior to grinding minimizes coolant penetration and contamination.
- Special processes: shot peening to densify metallic coatings, brushing for cleaning/decorative finish, and superfinishing/polishing for very low roughness.
- Chemical treatment:
- Sealing: important to close micro-porosity for hydraulic/pneumatic sealing, corrosion protection, altered friction (e.g., PTFE sealers) and specific surface properties (hydrophobic/hydrophilic, electrical insulation).
- Painting: guidance on painting timing for Zn/Al coatings (see related standards). Low-viscosity paints or wash primers are recommended for porous coatings to avoid blistering.
- Thermal treatment:
- Fusing for self‑fluxing alloys (see EN ISO 14920).
- Diffusion annealing should be performed in vacuum or inert atmosphere to avoid oxidation.
- Hot isostatic pressing (HIP) to increase density and adhesion where applicable.
- Health & safety: follow protective labour and environmental guidelines for all finishing processes.
- Annexes: include estimated values and guidance for chip cutting, grinding and abrasive selection.
Applications
ISO 14924:2005 is practical for:
- Surface engineers and coating specialists specifying post-treatment for thermal spray processes
- Manufacturing and repair shops performing machining, sealing, painting or HIP on sprayed components
- Industries using thermal spray coatings: aerospace, power generation, oil & gas, automotive, tooling, and corrosion protection
Related standards
- EN ISO 2063 (thermal spraying - Zn/Al coatings)
- EN ISO 14920 (spraying and fusing of self‑fluxing alloys)
- EN ISO 12944‑5 (protective paint systems)
This standard helps ensure consistent, damage‑free finishing of thermally sprayed coatings and guides selection of processes, tools and materials for optimal surface performance.
