BS 1224 Specification for Nickel and Chromium Electroplating Coatings

The standard "BS 1224 Specification for electroplating coatings of nickel and chromium" developed by the British Standards Institution (BSI) describes the requirements for determining the appearance, type, thickness, adhesion and corrosion resistance of nickel and chromium in the electroplating process of nickel (with copper primer if necessary), with or without a chromium top coat, on steel (or iron), zinc alloy, copper or copper alloys, aluminium or their alloys.

Nickel plating is a process that involves suspending parts (on a wire or jig) in a chemical bath and passing an electric current through them. This process results in a reaction where nickel is electrically deposited onto the parts, increasing their thickness. The standard thickness applied with nickel plating is 10-12 µm, but some modifications can be made if necessary. This process can be applied to steel and brass parts, and some aluminum parts are also possible. Nickel plating can be offered in a glossy or matte finish, with a barrel finish also available.

The main advantages of nickel plating are:

• Multiple passive color options available
• Provides excellent corrosion resistance
• Provides a good base for painting and powder coating
• Restriction of hazardous substances directive (ROHS) compliant options available
• Can provide a decorative appearance

BS 1224 is a British standard that specifies the properties of nickel and chromium electroplated coatings applied to various surfaces, typically used to improve corrosion resistance, surface hardness, and decorative appearance. This standard is primarily applied in industries where durable, corrosion-resistant, and aesthetically pleasing surfaces are important, such as automotive, consumer goods, plumbing, and architectural hardware.

The main objectives of this standard are:

• Standardize coating thickness and composition.
• To ensure the corrosion resistance of the product appropriate to its environment.
• To improve aesthetic quality by defining acceptable surfaces and surface conditions.
• To ensure durability and performance over time, including resistance to wear and tarnish.

The key features of the BS 1224 standard are:

• Coating structure: This standard specifies a layered structure consisting of:
  • A base layer of nickel: Nickel provides primary corrosion resistance. The nickel layer can be single-layered or dual-layered (double)—one with semi-bright nickel and the other with bright nickel for improved corrosion performance.
  • A top layer of chromium: The thin, hard and shiny chromium layer protects the nickel from tarnishing and increases its wear resistance.
• Thickness requirements: This standard outlines different coating thickness classes depending on environmental exposure:
  • Class 1: Heavy duty (e.g. automotive exterior components)
  • Class 2: Medium duty (e.g. indoor fixtures)
  • Class 3: Light duty (e.g. decorative items with low exposure)

Each grade has minimum thickness requirements for both nickel and chromium layers to ensure proper performance.

• Conditions of service: This standard specifies the following conditions of service according to environmental severity:
  • SC1 (light): Indoor, dry use (e.g. radiator valves)
  • SC2 (moderate): Occasionally damp indoor (e.g. shower fixtures)
  • SC3 (severe): Outdoor use under normal conditions
  • SC4 (exceptionally severe): High outdoor corrosion (e.g., salt exposure, acid rain, auto parts)

This standard specifies for each service condition and substrate:

• Minimum nickel thickness: 10µm (SC1) to 40µm (SC4) in steel, typically 30µm nickel in brass.
• The chrome thickness is nominal 0,3 µm regardless of service condition.
• Optionally, if using copper lining (approx. 20µm), the nickel thickness can be reduced (approx. 30µm on steel)

Service-specific tables cover substrate and layer system combinations, for example, steel with copper + nickel + chromium or nickel-only options.

• Substrate materials: While this standard focuses on coatings, it generally assumes that the substrates are: steel, zinc alloys (e.g., castings), and copper and copper alloys. Surface preparation of the substrate (cleaning, polishing, and possibly undercoating) is crucial for effective adhesion and durability.

BS 1224 standard includes the following provisions for accelerated corrosion tests:

• Neutral salt spray test: Simulates long-term exposure to salt-laden environments to evaluate coating performance.
• Microporosity and microcrack assessments: Chromium is naturally microporous or microcracked; testing ensures that pores or cracks are within acceptable limits to prevent corrosion.

Applications of coatings complying with this standard include:

• Automotive parts: Bumpers, grilles and trim.
• Plumbing fixtures: Faucets and shower heads.
• Furniture and fittings: Handles, hinges and decorative trim.
• Consumer electronics: Buttons, bezels, and handles.

The BS 1224 standard covers electroplating nickel (potentially onto a copper liner) and chromium, which is optional or mandatory depending on the application:

• Steel or iron
• Brass or zinc alloys
• Copper and its alloys
• Aluminum alloys

This standard addresses:

• Surface appearance and finish
• Adhesion to the substrate
• Coating thicknesses
• Corrosion resistance test
• Layer composition and quality requirements

The BS1224 standard contains detailed annexes that specify:

• Coulometric or microscopic measurement of chromium layer thickness.
• Adhesion tests (file, quench).
• Ductility tests.
• Sell ​​salt spray, acetic salt and Corrodkote corrosion test (an accelerated test used to determine the coating corrosion resistance of electrocoatings).
• Inspection criteria for cracks or microporosity of chrome layers.

As a result, BS 1224 provides a reliable framework for the specification and evaluation of nickel and chromium electroplated coatings, balancing both protective and aesthetic properties. Its widespread adoption ensures consistency in quality and performance across industries. Manufacturers and designers rely on this standard to ensure their products can withstand targeted environmental conditions while maintaining a high-quality finish.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the BS 1224 Specification for Nickel and Chrome Electroplating Coatings.