ISO 15726:2009

Overview

ISO 15726:2009 specifies requirements and designation methods for electrodeposited zinc alloy coatings with nickel, cobalt or iron. The standard covers composition ranges, minimum coating thickness guidance, appearance, adhesion, porosity, corrosion performance (neutral salt spray), and required information that purchasers must supply to electroplaters. It also defines designation rules for the coating sequence, chromate conversion coatings and supplementary treatments, and heat treatments to reduce hydrogen embrittlement.

Keywords: ISO 15726:2009, electrodeposited zinc alloy coatings, zinc-nickel, zinc-cobalt, zinc-iron, chromate conversion coatings, electroplating, corrosion resistance.

Key topics and technical requirements

• Scope and purpose
  • Requirements for zinc alloy electrodeposits (ZnNi, ZnCo, ZnFe) and their supplementary treatments.
• Composition and typical ranges
  • ZnNi (zinc–nickel): commonly 8% or 12% Ni; general range 6–18% Ni.
  • ZnCo: around 1.0% Co; range 0.3–1.2% Co.
  • ZnFe: around 0.5% Fe; range 0.3–1.0% Fe.
• Thickness guidance
  • Typical minimum local thickness values are provided (examples: ZnNi 5–10 µm guidance; ZnCo/ZnFe often specified higher).
• Designation system
  • Formal naming convention: “Electrodeposited coating - ISO 15726 - [basis metal]/[SR if any]/[alloy symbol(composition)thickness]/[chromate code]/[supplementary treatments]/[ER designation]”.
  • Example: ZnNi(12)5 designates 12% Ni, 5 µm thickness.
• Performance and testing
  • Requirements for appearance, adhesion, porosity tests, and corrosion resistance in neutral salt spray (referenced to ASTM B117 practice).
  • Guidance on sampling procedures and acceptance criteria.
• Hydrogen embrittlement
  • Pre- and post-plating heat treatments (stress-relief and hydrogen-embrittlement relief) are specified or to be agreed between purchaser and electroplater.
• Purchaser information
  • Purchasers must supply essential details: basis metal, surfaces to be plated, thickness, chromate type, porosity/adhesion test methods, heat-treatment needs, and sampling plan.

Applications

• Protective and decorative coatings for steel components where improved corrosion resistance is required (automotive body panels, fasteners, general hardware).
• Substitute for cadmium in many applications (noted especially for Zn–Ni alloys).
• Base for organic coatings or further sealants and conversion treatments.

Who should use this standard

• Electroplating shops and finishers
• OEMs and design engineers (automotive, aerospace, industrial equipment)
• Procurement and quality engineers specifying surface treatments
• Materials engineers assessing corrosion protection options

Related standards

Relevant references include ISO 2064, ISO 2080, ISO 9587, ISO 9588, ISO 10309, ISO 4518/4519 and ASTM B117 (salt spray). These are cited for measurement, sampling, porosity, and embrittlement controls.