Tag Archive for zinc

Rising Base Metals Rocketing to the Top?

Base metals are essential in the growth of the infrastructure, manufacturing and utilities sector of the UK.  The mining of base metals refers to major industrial non-ferrous metals like nickel, copper, tin and aluminium.  It is the dramatically increasing energy and urbanisation demand which are making the need for the metals rise, as well as the fact that they are used for automotive systems, metal coatings, electrical systems and make many goods more durable.  But will fluctuating prices negatively impact the base metal market?

 

Nickel Plating is Key

In 2019, Lead-zinc accounted for 24% of the global market and copper accounted for 16%.  Zinc was popular due to its specific characteristics, such as its unique bonding abilities with other metals, anti-corrosive properties and it has the ability to galvanise well.  The attributes have boosted its use considerably.  Copper is predicted to rise, forecast until 2023, thanks to its proven strength in the infrastructure sector.  The use of tin is also set to rise through the use of tin coating for electronic components in the automotive sector.  However, the most interesting sales increase seems to be a very specific area of the Nickel world to increase its sales – this seems to be nickel plating – though the reasons or sectors remain unspecified.

 

Information Regarding Nickel Plating

There are two types of Nickel Plating – Electroless Nickel Plating (ENP) and Diffused Nickel Plating.

Diffused Nickel Plating is a simple process which is the most effective nickel coating, ensuring a high resistance level against corrosion.  This is thanks to its total encapsulation plating method.  It has been proven that their corrosion resistance is more effective than that of the highest grade stainless steel, whilst at the same time being much cheaper.  Diffused Nickel Plating is the perfect plating method if your components are used in marine or salt environments.  This gives them a 30 year sub-sea guarantee.

In a similar way, Electroless Nickel Plating is a high quality but cost effective solution to metal coating which can extend the longevity of components dramatically.  It is creates a good resistance against corrosion and is often used in marine, oil and defence industries.    Electroless Nickel Plating prevents rust, wear and friction.  It can also be hardened through the use of heat treatment and is guaranteed not to chip or flake, like paint or varnish does.

Electroless Nickel Plating and Diffused Nickel Plating

A question often asked is…What is the different between the two types of Nickel Plating?  The basic answer is very simple – the plating processes used are very different.

It has already been deciphered that Diffused Nickel Plating occurs when the encapsulation plating method is performed but this is not the same as Electroless Nickel Plating.  The process for this occurs when a layer of even thickness metal is deposited evenly over the surface of a component, no matter what its shape.  The uniformity in its coating means that it is the perform plating method for components which are used in particular industries, such as Healthcare, Defence, Automotive and Aerospace, where the components are often not standard, need to be hygienic, regularly cleaned and are under constant stress.

Heat Treatment and Homogenising

When you think of heat treatment, I wonder what type of metal you associate it with?  Aluminium is probably not the first metal that springs to mind.  Why?  Because it is thought of as being a soft metal.  But there are certain, specific alloys which respond incredibly well to heat treatment, in fact, they actually respond in almost the same way as steel and iron.  So, what are the specific types of aluminium alloys?  They are aluminium alloys containing copper, zinc, or a blend of magnesium and silicon which enable them to respond well to the heat treatment process.  Be aware that pure aluminium and aluminium alloyed with manganese or magnesium does not work under heat treatment.  Therefore, when referring to the heat treatment process during this article, it is aluminium alloys containing copper, zinc or a blend of magnesium and silicon that is being referred to.

Harmonious Homogenising

Aluminium alloys come in to contact with the mold via their outside edge first, which forms a layer or skin of aluminium crystals, which are called grains.   This occurs when aluminium alloys are being cast.  They cool from the outside in, with the elements of the alloy precipitating which locks crystals in regionally.  This is how some areas become hard and some remain soft.  To even this imbalance out, we need homogenizing, so that redistribution of the precipitation can occur.  This means that the temperature needs to be taken to just below melting point which is between 900 and 1000 degrees farenheit.  Having reached the homogenizing temperature, the component is left to cool slowly, so that the internal structures uniformity is reached.

Annealing Aluminium Alloys

If you then require you aluminium alloys to be shaped, you will then require another process which is known as annealing.  The alloys must be heated once again to 570°F to 770°F for anywhere between thirty minutes to three hours, depending on the alloys composition and the component part.  Unlike the heat treatment or homogenising processes, the cooling process post annealing is not a critical factor in this process.

 

Why Use Electroless Nickel as an Alternative to Galvanisation?

The process of galvanisation

The process of galvanisation applies a protective coating of zinc onto the metal. This type of coating is commonly used on steel or iron in order to prevent rusting. Galvanisation prevents a ferrous item from rusting, as the corrosion resistance of zinc is much higher than that of steel or iron. Advantages of galvanisation are that it is relatively cheap and easily applied. It also has a very long life and needs little maintenance.

Hot dip galvanisation

Hot dip galvanisation is the most common method of galvanisation. The steel part is submerged in a bath of molten zinc, coating the component with a layer of zinc. Hot-dip galvanisation produces a grey, matte coating to the surface of the metal, which is very thick and durable.

Electroplated galvanisation

Galvanisation can also be achieved using electrochemical and electrodeposition processes. Electroplated coatings are generally less durable and not really appropriate for outdoor applications because the deposit is very thin. This can be helped by painting the surface of the component, which slows down zinc consumption, delays the corrosion and extending its durability.

The advantage of electroplating is that it is much cheaper than hot dip galvanising. It is used for many different outdoor applications but despite looking good when it is new, it isn’t very durable and won’t withstand the elements very well.

An alternative to galvanising

Although galvanisation is cheaper, the final finish isn’t as attractive or durable as some other types of metal finishing. Electroless nickel plating can be used as an alternative to galvanisation as it is durable and aesthetically pleasing.

Electroless nickel plating can also be used in harsh environments because of its high corrosion resistance. The uniform coating created by this process can be a perfect solution for critical high-end engineering items such as those used in the defense, healthcare, automotive and aerospace industries.

Considering the extent of its durability and the attractive finish it creates, electroless nickel plating is cheaper than you might think. It is also the ideal plating for a surface exposed to friction and wear, which can also be increased by using heat treatments.

If you would like to find out more about using electroless nickel plating as an alternative to galvanisation, contact us or email