Overview
EN ISO 26945:2011 (ISO 26945:2011) specifies requirements for electrodeposited tin‑cobalt alloy coatings of approximate composition 75–80 % tin (mass fraction), remainder cobalt. These tin‑cobalt alloy coatings are intended as a decorative chromium substitute with bright surface lustre for thin coatings in the 0.1 µm to 0.3 µm range. The standard covers application methods (rack and barrel plating), designation, inspection and testing requirements, and purchaser/processor information needed for contractual coating work. It does not prescribe the surface condition of the basis metal prior to electroplating.
Key Topics and Technical Requirements
- Alloy composition: Tin ~75–80 % by mass; remainder cobalt.
- Coating thickness: Typical decorative thickness specified between 0.1 µm and 0.3 µm.
- Performance comparison: Brightness similar to decorative chromium; hardness and wear resistance are not equivalent to chromium but are similar to tin‑nickel alloy coatings.
- Application methods: Suitable for rack plating and barrel plating-enabling economical treatment of nuts, bolts, rivets and complex shapes due to good current efficiency.
- Heat treatments: Addresses stress‑relief pre‑treatments and hydrogen‑embrittlement‑relief post‑treatments where relevant for iron and steel parts.
- Inspection & testing: Includes requirements for adhesion testing, quality‑evaluation tests, sampling plans, and measurement methods for coating thickness (see Annex A).
- Designation & ordering: Defines how coatings should be designated on drawings/orders and lists essential purchaser information (basis metal, finish, areas to be plated, thickness, tests, sampling and acceptance levels).
- Safety note: The standard warns users to follow applicable health, safety and environmental regulations when using electroplating chemicals and procedures.
Applications
- Decorative finish for fasteners, small components and articles where chromium‑like lustre is desired but chromium plating is not suitable or desirable.
- Economical plating of high‑volume, complex shapes using rack or barrel processes.
- Automotive trim, electrical fittings, hardware and other consumer or industrial parts seeking corrosion‑resistant decorative coatings with moderate wear properties.
Who Should Use This Standard
- Plating processors and metal finishers specifying or producing electrodeposited tin‑cobalt coatings
- Designers and procurement engineers selecting decorative coating alternatives to chromium
- Quality managers and test laboratories performing coating thickness, adhesion and embrittlement assessments
- Standards writers and compliance teams integrating plating requirements into product specifications
Related Standards
Commonly referenced standards for testing and procedures include:
Keywords: EN ISO 26945:2011, electrodeposited tin‑cobalt, tin‑cobalt alloy coatings, decorative chromium substitute, rack plating, barrel plating, coating thickness, hydrogen embrittlement, coating designation.