What are Non-Ferrous Metals?
Non-ferrous metals are alloys or metals that do not contain any appreciable amounts of iron. All pure metals are non-ferrous elements, except for iron (Fe), which is also called ferrite from the Latin ‘Ferrum,’ meaning “iron.”
Non-ferrous metals tend to be more expensive than ferrous metals but are used for their desirable properties, including lightweight (aluminum), high conductivity (copper), nonmagnetic properties, or resistance to corrosion (zinc).
Some non-ferrous materials are used in the iron and steel industries, such as bauxite, which is used for flux in blast furnaces. Other non-ferrous metals, including chromite, pyrolusite, and wolframite, are used to make ferrous alloys. However, many non-ferrous metals have low melting points, making them less suitable for applications at high temperatures.
There are a large number of non-ferrous materials, covering every metal and alloy that does not contain iron. Important non-ferrous metals include aluminum, copper, lead, nickel, tin, titanium, and zinc, and alloys such as brass.
Precious metals such as gold, silver, and platinum and exotic or rare metals such as cobalt, mercury, tungsten, beryllium, bismuth, cerium, cadmium, niobium, indium, gallium, germanium, lithium, selenium, tantalum, tellurium, vanadium, and zirconium are also non-ferrous. They are usually obtained through minerals such as sulfides, carbonates, and silicates. Non-ferrous metals are usually refined through electrolysis.
The difference between ferrous and non-ferrous metals is that ferrous metals contain iron. Ferrous metals, such as cast irons or carbon steel, have a high carbon content, which generally makes them vulnerable to rust when exposed to moisture. However, this is not the case for wrought iron, which resists rust due to its purity, and stainless steel, which is protected from corrosion by the presence of chromium.
Non-ferrous metals were the first metals used by humans for metallurgy. Gold, silver, and copper existed in their native crystalline yet metallic form. These metals, though rare, could be found in quantities sufficient to attract the attention of humans.
Less susceptible to oxygen than most other metals, they can be found even in weathered outcroppings. Copper was the first metal to be forged; it was soft enough to be fashioned into various objects by cold forging and could be melted in a crucible. Gold, silver, and copper replaced some of the functions of other resources, such as wood and stone, owing to their ability to be shaped into various forms for different uses.
Due to their rarity, these gold, silver, and copper artifacts were treated as luxury items and handled with great care. The use of copper also heralded the transition from the Stone Age to the Copper Age. The Bronze Age, which succeeded the Copper Age, was again heralded by the invention of bronze, an alloy of copper with the non-ferrous metal tin.
Recycling and pollution control
Due to their extensive use, non-ferrous scrap metals are usually recycled. The secondary materials in scrap are vital to the metallurgy industry, as the production of new metals often needs them. Some recycling facilities re-smelt and recast non-ferrous materials; the dross is collected and stored on-site while the metal fumes are filtered and collected.
Non-ferrous scrap metals are sourced from industrial scrap materials, particle emissions and obsolete technology (for example, copper cables) scrap.
Uses and Properties
Non-ferrous metals are used for a wide range of commercial, industrial, and residential applications. This may require careful material selection according to their mechanical properties, including how easily the metal can be shaped and whether these properties will be altered in the process.
Many of the properties of ferrous metals can be found in non-ferrous materials, for example, aluminum or titanium alloys can replace steel in some instances, and the magnetic properties of iron can be emulated by cobalt, nickel, or rare-earth elements that have been alloyed.
However, because non-ferrous metals are often more expensive, they tend to be used for their unique attributes rather than simply as a replacement for steel. These attributes include lighter weights, conductivity, corrosion resistance, and non-magnetic properties. Non-ferrous metals also tend to be softer and more malleable than ferrous metals, meaning they can also provide aesthetic applications, as with gold and silver.
The properties of non-ferrous metals include:
- Easy to fabricate (including machinability, casting, and welding)
- High corrosion resistance
- Good thermal and electrical conductivity
- Low density
Common Non-Ferrous Metals and Alloys
Because they include any metal that doesn’t include iron, there are lots of different non-ferrous metals and alloys.
Important List of Non-Ferrous Metals include:
Here are some of the properties and common uses of some of the more common non-ferrous metals:
Having been used by humans for thousands of years, copper is still widely used by industry. The addition of copper alloys, brass (copper and zinc), and bronze (copper and tin) have widened the uses for this non-ferrous metal further (see below for detail on these alloys).
The properties of copper and its alloys include high thermal conductivity, high electrical conductivity, good corrosion resistance, and high ductility.
These properties have allowed copper and its alloys to be used for heat exchangers and heating vessels, as an electrical conductor in wiring or motors, as a roofing material, for plumbing fittings, as well as for saucepans and statues. Copper also oxidizes to a green color.
Aluminum is an important metal that is used in a wide range of applications due to its low weight and ease of machining. Despite being a relatively expensive material, aluminum is also the base metal for many alloys.
Being corrosion resistant and a good conductor of heat and electricity (albeit less so than copper), as well as having good ductility and malleability, aluminum can require annealing as it becomes hard following cold working.
The lightweight aluminum makes it perfect for aerospace and automotive applications as well as for marine use in yachts. Aluminum is also found in bicycle frames, saucepans, and drink cans.
Lead has been used over the centuries for a range of applications, including for bullets, in fuels, and even in paint. However, it was found to be unhealthy when released into the atmosphere, while other applications also caused harm to users.
Lead is the heaviest common metal and is resistant to corrosion. It also doesn’t react with many chemicals and is soft and malleable.
Although many of its former uses are no longer allowed, lead is still widely used for batteries, power cables, and acid tanks.
Zinc has been used for centuries as an alloying element, particularly to alloy steel for a range of purposes as well as alloying copper to create brass.
Galvanizing materials with alloying elements offer them greater resistance to rust, affording it uses for chain-link fencing, guardrails, suspension bridges, lampposts, metal roofs, heat exchangers, and car bodies. Zinc is also used as a sacrificial anode in cathodic protection (CP) and as an anode material for batteries. Zinc oxide is also used as a white pigment in paints and to disperse heat during rubber manufacture.
Silver has been used as a precious metal for centuries. With the highest electrical conductivity, thermal conductivity, and reflectivity of any metal, silver is also soft and malleable when heated and is highly resistant to corrosion.
Used for jewelers and currency, silver can also be found being used in solar panels, for water filtration, in electrical contacts and conductors as well as for stained glass and even in specialized confectionary.
Another precious metal that has been used for jewelers and coinage, gold is the most malleable of metals as well as being ductile and resistant to corrosion and many other chemical reactions.
Its electrical conductivity has seen gold used in computer devices as well as for infrared shielding, for the production of colored glass, for gold leaf, and also for tooth restoration.
Titanium was first discovered in 1791 and offers good corrosion resistance and the highest strength-to-density ratio of any metallic element. Unalloyed, it is as strong as some steels yet less dense.
It can be alloyed with metals including iron and aluminum to create strong yet lightweight alloys for aerospace, automotive, agricultural, military, medical, and sporting uses as well as being used for jewelers and mobile phones.
What’s The Difference Between Ferrous and Non-Ferrous Metal?
The simple answer is that ferrous metals contain iron and non-ferrous metals do not. The more in-depth answer is that ferrous metals and non-ferrous metals each have their own distinctive properties. These properties determine the applications they are most suited for.
Non-ferrous metals have been used since the beginning of civilization. The discovery of copper in 5,000 BC marked the end of the Stone Age and the beginning of the Copper Age. The later invention of bronze, an alloy of copper and tin, started the Bronze Age.
The use of ferrous metals started in around 1,200 BC when iron production started to become commonplace. This ushered in the Iron Age.