What is Nickel? – Its Alloys, Properties, and Uses

What is Nickel?

Nickel, designated by the symbol Ni and carrying the atomic number 28, is a naturally occurring chemical element. Recognizable by its silvery-white luster, nickel stands out as a brilliant metallic substance that is found throughout the Earth.

This element ranks as the sixth most common on the planet, existing in considerable quantities within both the Earth’s crust and core. Much like iron, nickel appears frequently in meteorites and can be detected in small amounts across a range of environments—including plants, animals, and the oceans themselves.

Although nickel is the fifth most prevalent element on—and within—the Earth, its pure form is not commonly seen on the surface due to its tendency to react with oxygen. Instead, nickel is more stable when it forms compounds, especially alongside iron. This stability helps explain why nickel is so often found in iron-bearing ores and why it has proven indispensable in manufacturing stainless steel.

Nickel’s reputation for strength and resistance to corrosion has made it a key material for reinforcing metal alloys. On top of that, its ductility and malleability allow manufacturers to shape its many alloys into everything from wires and rods to tubes and sheets.

History of Nickel

Pure nickel was first isolated in 1751 by Baron Axel Fredrik Cronstedt, yet the metal itself had been recognized long before that. As early as around 1500 BC, Chinese records reference what they called “white copper,” almost certainly referring to a nickel-silver alloy.

Back in fifteenth-century Saxony, German miners encountered nickel ores and gave them the name kupfernickel, or “the devil’s copper.” They were convinced these ores would yield copper, but their efforts proved fruitless. Looking back, it’s likely that both the repeated disappointments and the ore’s high arsenic content—which must have posed health risks—contributed to the nickname.

Nickel’s story in metallurgy took a turn in 1889, when James Riley addressed the Iron and Steel Institute of Great Britain. Riley spoke about how nickel could enhance the properties of conventional steel, a point that drew considerable attention from the institute. His remarks coincided with the discovery of vast nickel deposits in New Caledonia and Canada, which made the prospect of large-scale use far more realistic.

By the early 1900s, new ore finds in Russia and South Africa made mass production of nickel feasible. The timing was notable—both World War I and World War II soon followed, leading to a surge in steel manufacturing and, consequently, a sharp rise in demand for nickel.

Alloys of Nickel

Nickel readily forms alloys with a wide range of metals, such as copper, chromium, iron, and molybdenum. When nickel is introduced to these metals, it alters the resulting alloy’s characteristics in useful ways.

For instance, alloying with nickel can enhance resistance to corrosion and oxidation, boost performance at elevated temperatures, or help manage thermal expansion. These modifications allow engineers and material scientists to tailor alloys to suit specific applications and operating environments.

Following are the alloys of nickel:

1. Nickel-Iron Alloys

Nickel-iron alloys have found their place in fields where maintaining a low rate of thermal expansion is crucial. For example, Invar—a well-known nickel-iron alloy—boasts a coefficient of thermal expansion that is roughly one-tenth that of typical carbon steel.

Thanks to their remarkable dimensional stability, these alloys are commonly chosen for use in precision measuring instruments and thermostat rods, where even slight changes in size could affect performance. Additionally, when the nickel content is increased, these alloys become valuable in soft-magnetic applications, making them suitable for components like transformer cores, inductors, and memory storage devices.

2. Nickel-Copper Alloys

Nickel-copper alloys are a category of nickel-based materials that typically contain between 29 and 33 percent copper. In their standard form, these alloys exist as a single-phase solid solution composed primarily of nickel and copper.

Some variants are designed to be heat-treatable by incorporating about 3% aluminum and 0.6% titanium. With these additions, the alloys can undergo precipitation hardening, which further improves their properties.

What stands out about nickel-copper alloys is their impressive resistance to both acids and alkalis. Alongside their strong corrosion resistance, these alloys offer high mechanical strength, notable flexibility, and a relatively low coefficient of thermal expansion.

On the practical side, machining these alloys can be challenging, which is worth considering for manufacturing. Despite this, their reliability makes them a common choice in chemical processing equipment, valve stems, springs, pumps, shafts, various fittings, heat exchangers, screw machine products, and even marine hardware.

3. Nickel-Chromium Alloys

Nickel-chromium alloys are valued for their impressive corrosion resistance, ability to withstand high temperatures, and notable electrical resistance. Take NiCr 70/30 as an example—this alloy melts at 1380°C and offers an electrical resistivity of 1.18 μΩ·m.

Common variants include Nikrothal 70, Resistohm 70, and X30H70. In everyday applications, these alloys often serve as heating elements, such as those found in toasters and various other electrical resistance heating devices.

4. Nickel-Molybdenum Alloys

Nickel-molybdenum alloys are known for their impressive resistance to a variety of strong acids and reducing agents. For example, they hold up well when exposed to substances like hydrochloric acid, hydrogen chloride, sulfuric acid, and phosphoric acid.

Take Alloy B-2, for instance—it typically contains about 29–30% molybdenum and 66–74% nickel in its composition. Because of this unique chemical makeup, it finds its place in several demanding industrial settings, including pumps and valves, gaskets, pressure vessels, heat exchangers, and piping systems.

5. Nickel-Chromium-Iron Alloys

Nickel-chromium-iron alloys bring together the strengths of all three elements, resulting in materials that hold up remarkably well against oxidation and corrosion, especially at elevated temperatures.

A notable example from this group is Alloy 800, often referred to by several names including Incoloy 800, Ferrochronin 800, Nickelvac 800, and Nicrofer 3220. This particular alloy finds its place in demanding environments, such as furnace components for the petrochemical industry—cracker tubes being a prime example—as well as in the sheathing for electrical heating elements.

One of the main reasons these alloys are so highly regarded is their reliable performance under long-term exposure to heat; they show excellent resistance to creep and rupture at high temperatures. Typically, their composition falls in the range of 30–35% nickel, 19–23% chromium, with iron making up at least 39.5%. Because of this substantial iron content, these alloys are often classified as stainless steel.

6. Nickel-Chromium-Cobalt Alloys

The addition of chromium and molybdenum to nickel alloys serves to enhance their resistance to creep rupture. Take Alloy 617 as a specific example: its composition typically includes 20–24% chromium, 10–15% cobalt, and 8–10% molybdenum, while the nickel content does not fall below 44.5%. This alloy is commercially available under names such as Inconel 617 and Nicole 617.

In practical terms, these alloys are chosen for demanding environments—think industrial furnace components, gas turbines, supports for nitric acid catalyst grids, and equipment used in fossil fuel production. Their particular mix of elements makes them especially suited to applications where high temperature strength and durability are essential.

7. Nickel-Chromium-Molybdenum Alloys

Among corrosion-resistant alloys, Alloy C-276 (N10276) stands out as one of the most recognized options. Its notable strength lies in its ability to withstand reducing acids, such as hydrochloric and sulphuric acid.

Over time, manufacturers have developed several variants of this alloy by adjusting the chromium and molybdenum content, and in some formulations, adding elements like copper or tungsten. These modifications are designed to enhance performance, depending on whether the environment is more oxidizing or reducing.

A few examples of related alloys include Alloy C-22 (N06022), Alloy 59 (N08059), Alloy C-2000 (UNS N06200), and Alloy 686 (N06686). Each offers its own balance of properties, tailored to suit different corrosion challenges.

8. Nickel-Titanium Alloys

Nickel-titanium alloys are known for their remarkable ability to retain and recover their original shapes. When an object is formed from this alloy at an elevated temperature, it can be deformed at a lower temperature, only to revert back to its initial configuration once it is reheated to what is referred to as the transition temperature. Interestingly, this transition temperature is not fixed; it can be adjusted by altering the alloy’s composition.

In addition to shape memory, these alloys exhibit a high degree of elasticity, which makes them particularly useful in applications such as shock absorption for stone structures, among other practical uses.

Ores of Nickel

1. Sulfides

Nickel, copper, and iron sulfides are commonly present in Canadian ore deposits. Among these, pentlandite—represented by the formula (Ni, Fe)₉S₈—stands out as the principal nickel-bearing mineral.

Pyrrhotite, which ranges in composition from FeS to Fe₇S₈ and frequently contains some nickel substituting for iron, is also significant. For copper, chalcopyrite (CuFeS₂) is the primary mineral encountered, with cubanite (CuFe₂S₃) occasionally appearing as well.

These ores often contain trace amounts of gold, silver, and all six metals of the platinum group. Efficient recovery of these elements is particularly important due to their value and rarity. Additionally, it is possible to extract cobalt, selenium, tellurium, and sulfur during the processing of these ores.

2. Laterites

Laterite ores develop through the weathering of peridotite, a process that leaves behind only a small percentage of nickel in the resulting material. In regions with subtropical climates, intense weathering tends to break down much of the original rock.

However, the nickel present in the rock does not simply disappear—instead, it dissolves and moves with the water, gradually traveling downstream. Over time, this movement can lead to the accumulation of nickel at concentrations high enough to make extraction and mining worthwhile.

Manufacturing of Nickel

Nickel is primarily extracted from two main groups of ores: the nickel sulfides—namely pentlandite, pyrrhotite, and millerite, which typically contain about 1% nickel—and iron-rich lateritic ores such as limonite and garnierite, which generally contain around 4% nickel.

The approach to separating nickel varies significantly depending on the ore type. Nickel sulfide deposits, which are prevalent in regions like the Canadian Shield and Siberia, are usually buried deep beneath the surface, making their extraction a demanding and costly endeavor.

Nevertheless, the actual separation of nickel from these sulfide ores tends to be less expensive compared to the processing of lateritic ores, like those found in New Caledonia. Another point worth noting is that sulfide ores often come with valuable trace elements, which can be recovered and add to the overall economic viability of the mining operation.

To process these sulfide ores, techniques such as froth flotation, hydrometallurgical methods, and magnetic separation are commonly employed to produce intermediate products—namely nickel matte and nickel oxide—with nickel concentrations ranging from 40% to 70%. These intermediates are further refined using the Sherritt-Gordon process, which is widely applied in industry.

Among the various refining methods available, the Mond Process (also known as the Carbonyl Process) is regarded as particularly efficient for nickel sulfides. In this process, the sulfide concentrate is first treated with hydrogen and then introduced into a volatilization kiln.

When heated to around 60°C, the material reacts with carbon monoxide, resulting in the formation of nickel carbonyl gas.

This gas is then allowed to decompose on the surface of pre-heated nickel pellets, which circulate through a heated chamber until they achieve the desired size. At higher temperatures, this same method can also yield nickel powder.

Lateritic ores, on the other hand, are usually processed using smelting techniques tailored to their high iron content. Due to their substantial moisture content—often between 35% and 40%—these ores must first be dried, typically in a rotary kiln furnace.

The drying step yields nickel oxide, which is subsequently reduced in electric furnaces operating at temperatures between 1,360°C and 1,610°C. Through this sequence, both Class I nickel metal and nickel sulfate can be produced.

Properties of Nickel

• Nickel is ferromagnetic, meaning it magnetizes easily at ambient temperature. 
• It is both malleable and ductile.
• Nickel has an atomic number of 28.
• Nickel’s resistance to heat, oxidation, and corrosion is one of its finest qualities.
• It is silver-white with a golden color.
• Nickel has a melting point of 1555°C, and a boiling temperature of about 2835°C nickel reacts with oxygen in its pure state.

Uses of Nickel

This natural element is now used in various applications, making it one of the most important metals. Some of the nickel’s important uses are listed below:

• Stainless steel uses over 65% of all nickel produced. 
• Nickel-metal hydride and rechargeable nickel-cadmium batteries are two types of batteries that contain the nickel element.
•  Hand-held power tools, camcorders, scanner radios, guitar strings, laptops, and cellular and cordless telephones are just a few examples of daily devices that contain nickel. 
• Desalination plants typically use a copper-nickel alloy to convert seawater to freshwater. 
•  Nickel is a good material for making wires because of its malleability and flexibility. 
• In gas turbines and parts of jet engines, superalloys made by combining nickel with iron or cobalt are employed.
• The nickel dimethylglyoxime compound is used as a colorant in cosmetics, paints, and some polymers.
• Nickel is also used for electroplating other metals using this natural material.

Advantages of Nickel

Nickel falls under the category of transition metals. What makes it particularly notable is its slow rate of oxidation at standard temperatures, which contributes to its hardness, malleability, and resistance to corrosion. In addition, nickel remains magnetic at room temperature and boasts a relatively high melting point.

• Corrosion Resistance: One of nickel’s key strengths is its natural resistance to corrosion. Even when it comes into contact with air, water, or various chemicals, nickel does not easily rust or degrade. This quality makes it a dependable choice for applications where exposure to harsh environments is unavoidable—for instance, in marine equipment.
• High Melting Point: Another notable feature of nickel is its ability to withstand very high temperatures, thanks to its elevated melting point. Because of this, it often finds a place in settings that demand thermal durability, such as furnace components or aerospace parts.
• Magnetic Properties: Nickel is also known for being magnetic, a characteristic that proves valuable in a range of practical uses. For example, manufacturers often rely on nickel in the production of electric motors and speakers, where its magnetism is essential.
• Non-Toxic Nature: It’s also worth pointing out that nickel is considered non-toxic. Unlike certain metals that can pose health risks, nickel’s safety profile makes it suitable for products that may touch food or come into direct contact with skin.
• Cost-Effectiveness: Despite offering several practical advantages, nickel remains relatively affordable when compared to other metals. This balance of performance and cost is one reason it is so widely used across different industries.

Disadvantages of Nickel

Excessive exposure to nickel, much like many other metals found in the environment, poses significant health risks to humans. For example, miners who are regularly exposed to airborne nickel compounds may develop severe allergic reactions, some of which can be life-threatening.

There is also a heightened incidence of conditions such as fibrosis and lung cancer among these workers. When elevated levels of nickel are present in the air, soil, food, or water, the risk of nickel poisoning for the general population becomes a genuine concern.

• Nickel as a Carcinogen: One of the most significant concerns associated with nickel is its classification as a carcinogen. In practical terms, this means that regular exposure to nickel has been linked to an increased risk of developing certain cancers, most notably those affecting the lungs and nasal passages. This connection has been supported by a variety of research studies over the years.
• Skin Irritation Caused by Nickel: Another point to consider is that nickel often acts as a skin irritant. For many individuals, even limited contact with nickel can result in skin inflammation or discomfort. In some cases, this irritation may progress to visible symptoms such as rashes or hives, making daily life uncomfortable for those affected.
• Respiratory Issues Related to Nickel Exposure: Breathing in nickel particles poses its own set of challenges. Individuals exposed to nickel, particularly in occupational settings, may develop respiratory problems including asthma or bronchitis. The metal’s ability to irritate the airways can make breathing difficult and exacerbate existing respiratory conditions.
• Impact on Liver and Kidneys: The potential for nickel to harm internal organs should not be overlooked. Research has shown that high levels of exposure can lead to liver damage, while even lower levels may place stress on the kidneys over time. These organs play crucial roles in maintaining overall health, so any damage can have serious long-term effects.
• Environmental Pollution: Beyond its effects on individual health, nickel also presents environmental risks. As an environmental pollutant, nickel has the potential to contaminate both soil and water. This contamination not only threatens plant and animal life but can also pose risks to people who rely on these natural resources.

Conclusion

Nickel is a robust, silvery-white metal with a distinct shine, and it’s surprisingly present in many aspects of daily life, showing up in places like the batteries of television remotes and the stainless steel that forms our kitchen sinks.

While most nickel alloys, such as stainless steel, are generally safe to handle, it’s important to be mindful when working with certain other nickel compounds, including metallic nickel itself. Research has found that some of these compounds carry health risks, including an association with cancer, making it essential to take extra precautions for those regularly exposed to them.

FAQs

References: 

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