ISO 17834:2003

Overview

ISO 17834:2003 - Thermal spraying - Coatings for protection against corrosion and oxidation at elevated temperatures - defines requirements for sprayed metal coatings used to protect components exposed to temperatures up to 1 000 °C (1 273 K). It covers selection of coating materials and processes, surface preparation and application timing, required coating characteristics, re-treatment of defects, and design recommendations to facilitate thermal spraying.

Keywords: ISO 17834, thermal spraying, sprayed metal coatings, high temperature corrosion protection, oxidation resistance.

Key Topics and Requirements

• Scope and applicability
  • Applies to metal (not non‑metal) sprayed coatings for protection against corrosion/oxidation up to 1 000 °C.
  • For atmospheric protection of iron/steel by sprayed aluminium and zinc, refer to ISO 2063.
• Coating materials
  • Typical choices: nickel/chromium alloys, iron/chromium/aluminium alloys, and metal/Cr/Al/Y alloys (metal = Ni, Co, Fe or alloys).
  • Blends with chromium carbide or other wear‑resistant phases are possible.
• Environmental considerations
  • The standard lists reactants to consider (oxygen, sulphur, chlorine, vanadium, potassium, sodium) and gives guidance on alloy selection depending on gas/salt chemistry (e.g., chromium and aluminium contents for molten salts; preference for Ni‑ or Fe‑based alloys depending on S or Cl levels).
• Coating thickness and tolerances
  • Nominal thicknesses are specified by service class (see Table 1); guidance example: ~0.2 mm for aluminium, ~0.4 mm for other materials.
  • Minimum local thickness: ≥ 75% of nominal; maximum local thickness: no more than nominal + 0.1 mm.
  • Thickness measured after each coating pass and before subsequent treatments.
• Application and pre‑treatment
  • Surfaces must be prepared per EN 13507 and sprayed as soon as possible - delay should not exceed 4 hours unless controlled storage is agreed.
  • Coating surface must be uniform and free from loosely adherent particles and contamination.
• Defect re‑treatment
  • Defective areas generally must be blasted clean before respraying; if only too‑thin, additional metal may be added if the surface remained dry and uncontaminated.
• Design guidance
  • Annex A recommends designing components for accessibility, avoidance of debris traps, and ease of inspection/maintenance.

Applications and Users

ISO 17834 is used by:

• Thermal spraying contractors and coating specifiers
• Materials and corrosion engineers
• Designers of high‑temperature plant (boilers, furnaces, heat exchangers, turbines, petrochemical equipment)
• Asset owners and maintenance teams specifying protective coatings for oxidation and high‑temperature corrosion

Practical benefits: improved component life at elevated temperatures, clearer specification of coating selection and quality controls, and reduced field failures.

Related Standards

• EN 1274 / ISO 14232 (thermal spray powders)
• EN 13507 (surface pre‑treatment)
• EN ISO 14919 (wires/rods for spraying)
• prEN ISO 2063 / ISO 2063 (aluminium/zinc for atmospheric corrosion)

Use ISO 17834 when specifying thermal spray coatings for high‑temperature corrosion and oxidation protection and when coordinating material selection, application, inspection and maintenance requirements.