Nickel: Definition, Composition, Types, Properties, and Applications

Nickel is a chemical element with the symbol Ni and atomic number 28, placing it in the transition metals group. Valued for its lustrous silver-white color, corrosion resilience, and unusually high melting point, it is often alloyed with other metals to enhance its properties. Nickel is alloyed with elements like copper, chromium, and iron to create an extensive range of alloys such as austenitic stainless steels, cupronickel, and Monel®. These alloys benefit from the corrosion resistance, heat resistance, ductility/malleability, and strength of nickel.

This article will discuss what nickel is, its composition, types, properties, and applications.

What Is Nickel?

Nickel is a transition metal element, number 28 in the periodic table. In wide use, it is applicable to alloying, imparting beneficial properties to the resultant materials which, in some cases, are still referred to as nickel.

What Is the History of Nickel?

Nickel’s history dates back to 3,500 BC in China where it was used in ornamental objects. Its identification as a distinct element was by Swedish chemist Axel Fredrik Cronstedt, who isolated nickel from a mineral called "kupfernickel" in 1751. Initially mistaken for a copper ore, "kupfernickel" proved to be a previously unknown metal. In the early 19th century, it was alloyed with silver to create "nickel silver." Nickel silver is a metal resembling silver in appearance, but considerably tougher and lower cost. Nickel's resistance to corrosion led to its widespread use in electroplating applications. The alloying of nickel in stainless steel by Harry Brearley in 1913 revolutionized various industries and created a whole new class of materials that are still being extended. Nickel's versatility, from adornments to essential industrial applications, has solidified its significance in modern society.

What Is the Other Term for Nickel?

Nickel has a variety of names, in its natural (ore) state: smaltite, garnierite, pentlandite, and millerite.

What Is Nickel Made Of?

Natural nickel consists of five stable isotopes: nickel-64 (0.91%), nickel-62 (3.59%), nickel-61 (1.13%), nickel-60 (26.10%), and nickel-58 (68.27%). It has a face-centered cubic crystal structure. It is a unique element that can only be broken down by nuclear reactions and high-energy bombardment.

How is Nickel Made?

Nickel is produced through a combination of mining, smelting, and refining processes, as it rarely occurs in the pure metallic state. It is generally found as a mineral salt. Nickel ores, typically containing nickel, copper, and other minerals, are mined. The ore is processed to extract nickel salts through crushing, grinding, and density sorting. The resultant nickel-salts concentrate is smelted in a reducing environment, to remove impurities and convert them into nickel matte. Refining is achieved through electrolysis or solvent extraction to purify the nickel from the unrefined and potentially complex alloy as-mined. The refined nickel is then generally added to a secondary smelting operation as an alloying agent. It is often in a carbon arc or induction furnace heated crucible, under a vacuum or inert atmosphere to enhance purity.

What Are the Characteristics of Nickel?

Nickel possesses a range of attractive and beneficial characteristics, both in its pure state and imparted to alloys of which it is a constituent. These characteristics are listed below:

1. Shiny silver-white lustrous appearance.
2. Very high resistance to corrosion and oxidation.
3. Versatile alloying agent, enhancing the properties of other metals, such as steel and copper with elevated strength, corrosion resistance, and heat tolerance.
4. Can retain its magnetic properties even after the magnetizing field is removed.
5. Both ductile and malleable.
6. Of lower conductivity than copper, but nickel still possesses low resistance which is useful in electrical and electronic applications.
7. High thermal conductivity.
8. Biocompatibility and resistance to corrosion within the body.
9. Various nickel compounds are important catalysts for chemical processes.
10. Radioactive isotopes of nickel (Ni-63 for example) are key radiation sources for scientific and industrial purposes.

What Is the Color of Nickel?

When refined and polished, nickel offers an undisturbed reflection of visible light. This implies that a mirror finish offers a “true color” reflection which is generally described as a “silver” finish. In its natural, unrefined metallic state, nickel is often contaminated with other metals which alter its reflectivity. Combination with copper, for example, lends a red hue to the reflective property.

What Does Nickel Look Like?

In its unrefined state, it is generally distributed as salts, mixed in with ores of other metals and various minerals. When first smelted, it will often look dull gray in the relatively pure state. It may also take on the color of the other metals the nickel is mixed with—commonly copper, lending red-brown coloration of the more readily oxidized copper. The refined and purified element is lustrous silver as shown in Figure 1 below:

What Are the Different Types of Nickel?

In addition to nickel ores and pure nickel, the metal exists in a wide spectrum of alloys and is commonly used as nickel plating. Listed below are the main types of nickel:

1. Magmatic Sulfide

Magmatic sulfide describes valuable mineral deposits formed within mafic and ultramafic igneous rocks through magmatic processes. These deposits contain minerals particularly rich in the metals nickel, copper, and platinum.

Whenever magma cools and crystallizes, sulfide minerals of higher density tend to sink and segregate. This produces elevated concentrations of higher-density metal salts. These deposits are often found in igneous geological complexes, particularly in layered intrusions or volcanic conduits. Magmatic sulfides are vital in global metal supply, as pre-concentrated deposits that render high value in mining and refining.

2. Laterites

Laterites are weathered soils and rock formations. They are generally characterized by a distinctive red or brown color and high levels of iron and aluminum oxides. Laterites are formed in tropical and subtropical regions with heavy rainfall and higher environmental temperatures. They develop as a result of intense chemical weathering over extended periods. This process leaches minerals from the upper layers and concentrates metallic salts in the lower layers because of their generally higher densities. Laterites are commercially valued for extraction as they can also contain concentrations of high-value minerals like nickel and cobalt.

What Are the Physical Properties of Nickel?

Properties of nickel alloys diverge greatly depending on a wide range of other constituents and proportions. Table 1 below lists the physical properties of annealed pure nickel:

What Are the Chemical Properties of Nickel?

Table 2 shows some very useful chemical properties of nickel which it imparts to alloys it is part of:

What Are the Uses of Nickel?

Nickel's versatility lends itself to a wide range of applications:

1. It's a crucial component in stainless steel, increasing corrosion resistance, and ductility when used as a 5–18% component.
2. Nickel alloys like Inconel® and Monel® are critical in aerospace, petrochemical, and marine industries due to their high strength and resistance to extreme temperatures and corrosive environments.
3. Essential in battery technology (nickel-cadmium and nickel-metal-hydride batteries) though this use is diminishing.
4. Its electrical conductivity makes it valuable in electrical components and wiring.
5. Used in plating to provide decorative and protective coatings on steel and brass.
6. It's utilized in implants and devices due to its high biocompatibility and resistance to plaque deposition.

What Are the Common Commercial Forms of Nickel and Nickel Alloys?

Some of the common forms of nickel and nickel alloys are listed and discussed below:

1. Nickel Tubing

Nickel tubing includes small- and large-bore tubes or pipes made from nickel or more commonly nickel-containing alloys. These are produced by rolling/welding from a sheet or by rotary piercing and drawing, for example in a Mannesmann mill. These tubes are extensively used for various industrial, medical, and commercial applications. They generally offer high corrosion resistance, high maximum service temperature, and excellent general mechanical properties, fitting the needs of a wide range of applications and industries. 

Nickel alloy tubing is used in chemical and pharmaceutical processing equipment in corrosive environments in which resistance to acids, alkalis, and other chemicals is vital. The oil and gas production and refining sectors use nickel alloy tubing in oil refineries and production facilities, exploiting resistance to corrosive conditions and high-temperature environments. It is used in power plants for heat exchangers, steam generators, and condensers, benefitting from high thermal conductivity and operating temperatures.

Nickel alloy tubing is manufactured in a striking range of sizes from microbore gas transport tubes to huge oil pipelines. Alloys such as Inconel®, Monel®, and Hastelloy® and a range of more basic stainless steels are widely used. Their selection is based on factors such as: the operating environment, temperature, commodity price, and required mechanical properties.

2. Nickel Sheet

Nickel-containing alloy sheet stock of a range of thicknesses and stock widths is available for use in virtually all industrial and commercial applications. These materials offer varied levels of corrosion resistance, high-temperature stability, and mechanical properties, suiting a similar range of roles to those for tube products.

They are used in: chemical, food processing, pharmaceutical, energy, and power generation, aerospace and aircraft components and structures, oil & gas extraction and refining, marine equipment, medical equipment, and automotive applications. Nickel alloy sheet stock is gauged to suit specific requirements and cover the full range of nickel alloy materials.

3. Permalloy Nickel Alloy

Permalloy, more commonly known as Mu-metal (or 𝜇metal), is a magnetic alloy of nickel and iron, with trace quantities of other elements like molybdenum and copper. It possesses a very high magnetic permeability, making it highly desirable in shielding.

Mu-metal sheets or plates are utilized for forming magnetic shields, enclosures, and barriers that protect sensitive components from external magnetic fields. These sheets are used in electronics, telecommunications, scientific instruments, and various industrial applications in which precise control over magnetic interactions is essential. The high permeability of permalloy makes it particularly important in magnetic field shaping and concentrating in transformer cores.

4. Nickel Plates

Nickel metal and alloy plates of a variety of thicknesses and stock widths are used for producing machined components. These materials possess good to excellent corrosion resistance, varied levels of maximum service temperature, and other characteristics such as: strength, toughness, and ductility. They find applications across all industries: chemical, food processing, pharmaceutical, energy and power systems, aerospace and rocket components and structures, oilfield equipment and refineries, marine products, medical systems, industrial equipment, consumer goods, and ICE applications. Nickel alloy plates are gauged to suit requirements and cover an extensive range of nickel alloys.

What Are the Advantages of Nickel?

Nickel offers a range of advantages due to its unique properties.

1. Possesses exceptional corrosion resistance, ideal for use in acidic and alkaline environments.
2. High strength, durability, and resistance to high temperatures make it valuable in high-stress applications.
3. Nickel's good electrical conductivity finds application in electronics, connectors, switches, and bus bars.
4. Its magnetic properties are useful in sensors and magnets.
5. Biocompatibility allows its use in medical implants.
6. Its versatility in alloying allows fine adjustments in alloy properties across various metal families.
7. Nickel's aesthetic appeal, combined with corrosion resistance makes it useful in decorative applications.
8. Its catalytic and electrochemical properties are useful in battery and chemical reaction applications.
9. Its weldability enables this process in a range of alloys.

What Are the Disadvantages of Nickel?

Despite its benefits, nickel also has various disadvantages.

1. Nickel allergies are common, causing skin reactions in sensitive individuals.
2. Its cost is relatively high, significantly impacting the price of its alloys.
3. Additional complexity in the welding processes of some nickel-bearing alloys demands expertise and specialized techniques, increasing production costs.
4. Nickel's limited availability and supply chain disruptions can lead to price volatility.
5. The environmental impact of nickel mining and processing includes habitat disruption, water pollution, and significant electrical energy consumption.
6. Certain nickel compounds are toxic when inhaled or ingested, posing health risks—particularly in mining and refining facility workforces in lower-regulation regions. 
7. Machining nickel alloys can be challenging due to their hardness and severe work-hardening, requiring advanced tooltips and specialist skills.
8. Oxidation risk rises at high temperatures; this may limit its use in extreme environments.
9. Nickel's reactivity with particular substances can constrain its applications.

Is Nickel Rustproof?

Yes, nickel is rustproof. Although nickel itself does not rust, it can corrode under certain aggressive chemical conditions. Nickel is resistant to oxidation and most forms of corrosion due to its ability to form a tough, protective oxide layer on its surface. This oxide layer acts as a barrier, preventing further interaction between the metal and its environment. Its resistance to corrosion recommends it for applications that require materials to withstand harsh conditions, such as: exposure to moisture, acids, alkalis, and most corrosive substances. This explains why nickel-containing alloys are widely used in industries such as: aerospace, chemical processing, and marine engineering.

While nickel itself doesn't corrode, the iron content of various nickel-containing alloys can still do so under extreme conditions, especially in the presence of aggressive chemicals. This is often seen as pitting and brown staining of moderate-quality alloys, in the presence of chloride ions such as those present in seawater. Nickel content tends to impart better corrosion properties to the resultant alloys it is included in.

Can Nickel Be Welded?

Yes, nickel and nickel alloys can generally be welded, although this can be more challenging than welding plain carbon steels. Welding of nickel requires careful consideration of factors such as: the specific alloy composition to be matched in filler rod/wire, joint design to minimize sensitization (fracture), and welding techniques.

Note that because of nickel's high thermal expansion coefficient and relatively low thermal conductivity, assiduous preheating, and post-weld heat treatment are often necessary to avoid cracking and distortion. Additionally, selecting the right filler material compatible with the base metal's composition is key in avoiding localized alloy variations that can result in the concentration of corrosion or localized degradation of properties at the joint.

Is Nickel a Metal?

Yes, nickel is an elemental metal that is a constituent in a variety of alloys that are also metals.

Is Nickel Expensive?

Yes. Nickel is a considerably more expensive metal than many. The current price range is around $21,000 per metric ton, whereas steel, for example, sells at around $750 per metric ton.

Is Nickel a Transition Metal?

Yes, nickel is a transition metal, along with many of the widely exploited and valued commodity metals. 

What Is the Difference Between Nickel and Nickel Alloy?

Nickel is an element, atomic number 28, and it is indivisible by any but nuclear bombardment means. Nickel alloys are metal blends that contain a measurable quantity of nickel that is usually in a solid solution with other metals such as iron, copper, etc.

What Is the Difference Between Nickel and Aluminum?

The differences between pure nickel and aluminum are very large, despite some similarities in properties. These differences are shown in Table 3:

Summary

This article presented nickel, explained it, and discussed its composition and various types. To learn more about nickel, contact a Xometry representative.

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Copyright and Trademark Notices

1. Monel® is a registered trademark of Special Metals Corporation.
2. Inconel® is a registered trademark of Special Metals Corporation.
3. Hastelloy® is a registered trademark of Haynes International, Inc.

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