Chromium (Cr) – The discovery of chromium, its origins and wide-ranging industrial and aesthetic applications

Metals added to stainless steel include Chromium (Cr).

Chromium is an element - atomic number 24 - and it has an atomic weight of 51.9961. Chromium sits in the periodic table between the metals vanadium and manganese and possesses a beautiful and appealing color, being a mainly lustrous silvery-white.

Shown here are high purity chromium crystals and a polished chromium cube with very different textures but both demonstrating the characteristic lustrous silvery-white colour.

Shown here are high purity chromium crystals and a polished chromium cube with very different textures but both demonstrating the characteristic lustrous silvery-white colour.

The origins of chromium

Chromium is a beautiful and useful element - the name comes from the Greek word for color, chroma. It was discovered in 1797 by the French scientist, Professor Nicolas Louis Vauquelin. Professor Vauquelin is held to be the father of modern metallurgy. He was born in Saint Andre d'Hebertot in May 1763 and passed away on the 14th November 1829 after a remarkably distinguished career, which included the discovery of a second element, the metal beryllium. Beryllium made nuclear weapons possible, so a little bit of a double-edged sword there.

Prof Louis Nicolas Vauquelin (16 May 1763 – 14 November 1829) was a French pharmacist and chemist. He was the discoverer of both chromium in 1797 and beryllium in 1798.

Prof Louis Nicolas Vauquelin (16 May 1763 – 14 November 1829) was a French pharmacist and chemist. He was the discoverer of both chromium in 1797 and beryllium in 1798.

Professor Vauquelin chose the name chromium because the metal can produce many vivid colors when dissolved in various chemical solutions.

Chromium in paint

Chromium ores were used extensively in the paint industry; for example, the pigment chrome yellow was very popular with artists and the paint industry. Chrome was an essential ingredient in the paint that was originally used to paint American school buses. These bright yellow buses are a part of American daily life.

The yellow school bus is an easily recognisable part of American culture and yellow paint derived from chromium ore was originally used to paint these buses.

The yellow school bus is an easily recognisable part of American culture and yellow paint derived from chromium ore was originally used to paint these buses.

However, paint manufacturers discovered that the yellow color they were applying was poisonous due to the heavy metals in it.

Chromite

It was recently estimated that there are 11 billion tonnes of minable chrome in the earth's crust, making it the 21st most abundant element on the planet. That is not all the available chromium, that is the material we can reach using today's technology.

The most commercially important ore containing chromium is chromite. Chromite ore deposits have been uncovered in South Africa, Zimbabwe and Finland. Smaller but still precious chromite deposits are located in the USA, Russia and Greenland.

In 2018 we mined well over 30 million metric tonnes of chromite.

The vast Bushveld Igneous Complex of South Africa is a large layered mafic to ultramafic igneous body with some layers consisting of 90% chromite making the rare rock type, chromitite.

The vast Bushveld Igneous Complex of South Africa is a large layered mafic to ultramafic igneous body with some layers consisting of 90% chromite making the rare rock type, chromitite.

Chromium in humans

Chromium like lots of other elements is vital for human health. It is thought that chromium influences how insulin functions and the organ with the most amount of chromium in it is the placenta. The recommended daily intake for an adult human is between 25 and 35 micrograms per day - a tiny amount!

It is also critical for animals who, if denied all chromium in their diet, develop diabetes.

Industrial uses

One of chrome’s most essential roles in industry is that is can be alloyed with iron, nickel and other metals to produce stainless steel. Some stainless steels can contain up to 25% chrome in their formula.

Another well-known use for chrome is in the plating industry. For years, every car produced all over the world had many chromed parts fitted. From bumpers to door handles, a thick layer of lustrous chrome was considered to add value and visual appeal.

The process of applying a layer of chromium to steel, known as chrome plating, was used extensively in the car industry to add aesthetic appeal and durability. Photo credit: GmanViz

The process of applying a layer of chromium to steel, known as chrome plating, was used extensively in the car industry to add aesthetic appeal and durability. Photo credit: GmanViz

Unfortunately, chrome plating is considered by many to be an incredibly damaging process for the environment. This view is gaining ground because chrome plating uses many dangerous acids and chemicals that are very harmful to both people and to the environment. As a result, chrome plating is falling quickly out of favour in many countries and is likely to become a thing of the past in the next few years.

Alternatives to chrome plating

Apart from chrome vinyl wrapping the only other alternative to chrome is PVD (Physical Vapour Deposition) colored stainless steel. With the production of vinyl being notoriously full of dangerous chemicals this really only leaves PVD as the environmentally friendly option. The PVD process does not require acids or other harmful chemical solutions to be used, which means cleaning a PVD plant is minimal compared to cleaning a chrome plating plant. PVD does not produce a harmful waste product, unlike chrome plating, and the process itself does not produce harmful vapours.

To learn more on the PVD process read:- The basics of Physical Vapour Deposition by architect, Federico de Paoli

Lever handle in PVD coloured stainless steel. PVD is a more environmentally friendly alternative to chrome plating as it does not produce a toxic waste product.

Lever handle in PVD coloured stainless steel. PVD is a more environmentally friendly alternative to chrome plating as it does not produce a toxic waste product.

As chemical elements metals make up twenty-five per cent of the Earth’s crust and have been since Copper was first used 11,000 years ago.

The process of anodization and its early applications in aviation through to modern day consumer electronics - Double Stone Steel

The process of anodization and its early applications in aviation through to modern day consumer electronics

Richard Storer-Adam explains how metals are altered through anodizing and the anti-corrosive benefits and coloring options this process provides to product manufacturers.

The applications of Cor-Ten steel - from its beginnings in the US railroad industry to the worlds of art and architecture - Double Stone Steel

The applications of Cor-Ten steel - from its beginnings in the US railroad industry to the worlds of art and architecture

Richard Storer-Adam runs through how this weathering steel alloy quickly moved beyond transport uses to give a distinct, rusted look to some iconic buildings and sculptures.

Nickel (Ni)  – part of a series on metals commonly alloyed with stainless steel to form varying grades of material. - Double Stone Steel

Nickel (Ni) – part of a series on metals commonly alloyed with stainless steel to form varying grades of material.

Richard Storer-Adam looks into the origins of nickel, the part it plays in the composition of the planet and the industrial uses that make it a valuable metal alloy.

Titanium (Ti) – a brief history of the origins and commercial applications of titanium - Double Stone Steel

Titanium (Ti) – a brief history of the origins and commercial applications of titanium

Richard Storer-Adam begins a series on metals commonly alloyed with stainless steel to form varying grades of material.

The Acid Etching process on stainless steel and other metals. - Double Stone Steel

The Acid Etching process on stainless steel and other metals.

An explanation of the truly ancient art of engraving, etching and intaglios on copper, mild steel, aluminium, brass and stainless steel by Richard Storer-Adam.

An introduction to hard-anodised aluminium coatings, their advantages and environmental implications for architectural cladding - Double Stone Steel

An introduction to hard-anodised aluminium coatings, their advantages and environmental implications for architectural cladding

An analysis of the color and corrosion properties of aluminium cladding, its maintenance and waste products.

An exploration of metals, elements and alloys. We look at how these naturally occur on Earth and how they are treated through processes of colouring, plating, etching, anodising and Physical Vapor Deposition to become materials and products used in industry, construction, art, decoration and jewellery.

The process of anodization and its early applications in aviation through to modern day consumer electronics - Double Stone Steel

The process of anodization and its early applications in aviation through to modern day consumer electronics

Richard Storer-Adam explains how metals are altered through anodizing and the anti-corrosive benefits and coloring options this process provides to product manufacturers.

The applications of Cor-Ten steel - from its beginnings in the US railroad industry to the worlds of art and architecture - Double Stone Steel

The applications of Cor-Ten steel - from its beginnings in the US railroad industry to the worlds of art and architecture

Richard Storer-Adam runs through how this weathering steel alloy quickly moved beyond transport uses to give a distinct, rusted look to some iconic buildings and sculptures.

Nitrogen (N) - part of a series on gases used during the physical vapour deposition (PVD) process - an innovative method for improving the performance of stainless steel - Double Stone Steel

Nitrogen (N) - part of a series on gases used during the physical vapour deposition (PVD) process - an innovative method for improving the performance of stainless steel

Richard Storer-Adam investigates the paradoxical role nitrogen plays in both saving and destroying life as a critical element in the manufacture of explosives, agri-fertilisers and airbags.

Oxygen (O) - part of a series on gases used during the physical vapour deposition (PVD) process - an innovative method for improving the performance of stainless steel - Double Stone Steel

Oxygen (O) - part of a series on gases used during the physical vapour deposition (PVD) process - an innovative method for improving the performance of stainless steel

Richard Storer-Adam explores the controversial discovery of oxygen, its importance to the human body and how it’s reactivity can be a vital component of metal manufacture.

Nickel (Ni)  – part of a series on metals commonly alloyed with stainless steel to form varying grades of material. - Double Stone Steel

Nickel (Ni) – part of a series on metals commonly alloyed with stainless steel to form varying grades of material.

Richard Storer-Adam looks into the origins of nickel, the part it plays in the composition of the planet and the industrial uses that make it a valuable metal alloy.

Titanium (Ti) – a brief history of the origins and commercial applications of titanium - Double Stone Steel

Titanium (Ti) – a brief history of the origins and commercial applications of titanium

Richard Storer-Adam begins a series on metals commonly alloyed with stainless steel to form varying grades of material.