Nickel Plating Steel, Aluminium and Brass

The process of electroless nickel plating produces a nickel alloy that can be deposited without using an external power source. The electroless nickel solution involved consists of nickel ions, reducing agents and other chemicals. The most commonly used reducing agent is sodium hypophosphite. Nickel phosphorous alloys can be deposited on to specially activated surfaces, which act as a catalyst.

The metal layer deposited by the electroless nickel plating process has the advantage of having an even thickness over all surfaces of the component, virtually regardless of its shape. This effect cannot be achieved with electrodeposited coatings.

Before the electroless nickel plating process can begin, the parts have to be treated suitably. Electroless nickel solutions operate specifically according to their end requirements in a pH 4-9 medium at a temperature of between 25-92 degrees centigrade. The thickness of the nickel deposit depends on the operating conditions and time. Depending on solution composition and working parameters it is possible to deposit nickel phosphorous alloy layers with a phosphorous content between approximately 2 and 14% by weight.

It is possible to plate almost all metals including stainless steel, steel, aluminium and its alloys, and brass. It is also possible to plate non-conductive materials such as plastic and ceramics. Each type of material requires a specific pre-treatment method. The quality of the electroless nickel deposit is dependent upon the quality and surface finish of the substrate material. In contrast with many electroplated nickel coatings the electroless nickel deposit reproduces the substrate surface finish.

To find out more about electroless nickel plating and how it can be used as analternative to galvanisation, please visit our website at http://www.electroless-nickel-plating.co.uk

Advertisements

Types of Metal Finishing

Electroplating 

Electroplating occurs when an electric current is passed through a solution which contains the metal object and it acts as a cathode. Aluminum, cadmium, bronze, brass, copper, gold, chromium, lead, iron, platinum, nickel, tin, silver and zinc can all be used for plating ferrous and non-ferrous objects.

Electroless Plating

During electroless plating no electric current is passed. The chemical is deposited on the metal product causing a chemical reaction. Salt (source metal), complexing agent, reducer, various buffers and other chemicals are used to complete the process. Copper and nickel are commonly used in printed circuit boards.

Immersion Plating

Immersion plating is very similar to electroless plating, but unlike electroless plating which uses a mixture of two chemicals, immersion plating creates the metal plating reaction through the metal substrate. This process displaces the chemical, producing a thin metal deposit on the product. Immersion plating is proven to create more waste than electroplating and electroless plating.

Other methods of metal finishing include cladding, case hardening, galvanized coatings, electro-polishing and metallic coatings.

Electroless Nickel Plating as an Alternative to Galvanisation

What is galvanisation?

When a metal is galvanised, a protective zinc coating is applied to it. This zinc coating is applied to steel or iron in order to prevent rusting.

Galvanising is used predominantly for protecting metals such as steel or iron with a coat of zinc. Galvanisation is an effective way of preventing the ferrous item from rusting, as the corrosion resistance of zinc is much higher than iron or steel.

It is also a cheap process, easily applied and has a long maintenance – free service life.

How is galvanisation achieved?

The most common method of galvanisation is called hot-dip galvanisation. Hot dip galvanisation is the process of submerging the steel parts in a bath of molten zinc. However, this process is also achievable through electrochemical and electrodeposition processes.

There are some differences between these processes. Hot-dip galvanisation produces a grey, matte coating to the surface of the metal, which is very thick and durable. Electroplated coatings are less durable and unsuitable for outdoor applications because of the thinness of the deposit. This can be overcome to some extent by painting the surface which slows down zinc consumption, therefore delaying the corrosion and extending its durability.

Electroplating on its own is cheaper than hot dip zinc coating. Therefore it is used for a number of outdoor applications, as it looks good when new, despite its relatively short durability and low resistance to the elements.

Electroless nickel plating as an alternative to galvanising.

Electroless nickel plating can be used as an alternative to galvanisation as it is both durable AND aesthetically pleasing. Not only does electroless nickel plating provide enough corrosion resistance to be used in harsh environments, the uniform coating it creates can be a perfect solution for critical high-end engineering items such as those used in the defence, healthcare, automotive and aerospace industries.

Electroless nickel plating is also much cheaper than you would imagine, considering the extent of its durability, and the wear resistance of the surface can be increased by using heat treatments. This makes it an ideal specialist plating where friction and wear may be problematic with regard to the use of the component.

To find out more about electroless nickel plating and how it can be used as an alternative to galvanisation, please visit our website at http://www.electroless-nickel-plating.co.uk

Electroless Nickel Plating and its Uses in Architecture

Electroless nickel plating can be used to coat mild steel or aluminium for external use on buildings, as is great for corrosion resistance. It can also be used as a cheaper alternative to stainless steel.

Electroless Nickel Plating can also be used as an alternative to galvanizing, powder coating or even stainless steel for balustrades, balconies and feature stairs.

Repairs and alterations to electroless nickel plated materials can be done on site. Although the nickel plated pieces would be prepared off site, the size of the tanks used to nickel plate the components are very large, therefore resulting in much fewer joins.

Expected lifespan

The expected lifespan for electroless nickel plated materials depends on the specific project, as certain factors affect the lifespan, (for example, salt spray by the sea.) Electroless nickel plating usually lasts decades.

Did you know?

-NiTEC nickel plated a staircase in the The Natural History Museum’s glass extension ‘The Darwin Centre’.

-Electroless nickel plating could also be used to treat steel cladding panels as a feature type material.

To find out more about electroless nickel plating, visit http://www.electroless-nickel-plating.co.uk for more information.