Different Types of Nickel Alloys

There are many different types of nickel alloys. Some common grades are listed below:
1. Inconel®
Inconel® is a trade name for a nickel alloy whose main alloying elements are chromium, molybdenum, and iron. It is known for its oxidation resistance, excellent performance in high temperature environments, and mechanical strength. Due to its rapid work hardening characteristics, Inconel® is difficult to cold form. Typical alloys are Inconel 625, 718, and 600.
2. Monel Alloys
Monel® is a trade name for a group of copper-based nickel alloys. Monel has high strength and excellent salt water resistance, and is able to perform well in low temperature environments, that is, ductility is not greatly reduced, and hardness and strength are increased. Monel® tends to harden during cold forming, making it difficult to process. Typical alloys are Monel® 400, R-405, and K-500.
3. Hastelloy Alloys
Hastelloy® is a trade name for a nickel-chromium or nickel-molybdenum alloy that is extremely corrosion resistant. Hastelloy® also has good thermal stability and is used in the aerospace and chemical processing industries. Typical alloys include C-22 and C-276.
4. Nickel-Copper Alloys
Nickel-copper alloys have excellent resistance to saltwater corrosion and fouling. Therefore, they are widely used in the marine industry. Iron, tin, and manganese are sometimes added to further improve corrosion resistance. The copper content can be 55% to 91.5%, with nickel being the second largest alloying element. The other alloying elements make up a small portion of the total weight. Monel® is considered a nickel-copper alloy.
5. Nickel-Iron Alloys
Nickel-iron alloys have good ductility, low thermal expansion, and corrosion resistance. These alloys also have soft magnetic properties. These alloys are used in applications that require low thermal expansion, such as sensitive scientific equipment, or applications that require soft magnetic properties, such as transformers. A common trade name for nickel-iron alloys is Invar®.
6. Nickel-Chromium Alloys
Nickel-Chromium alloys have excellent resistance to corrosion and oxidation, while retaining their strength at high temperatures. They also have high electrical resistivity. This makes nickel-chromium alloys particularly suitable for use as heating elements, such as those in ovens or toasters. The melting point of nickel-chromium alloys can exceed 1300°C. The nickel content of these alloys is usually high, at 70%.
7. Nickel-Titanium Alloys
Nickel-Titanium alloys have excellent corrosion resistance and good mechanical strength. However, the most interesting property is that they are a type of shape memory alloy (SMA). They can be formed into a specific shape above a certain high temperature, called the transformation temperature. When cooled, the part can be deformed to a certain degree, but if it is heated back to the transformation temperature, it will return to its original shape. The exact temperature at which this change occurs can be adjusted by varying the composition of the alloy. These alloys are particularly useful in medical applications. For example, a stent can be inserted in a compressed form, but expand to its final shape once inside the body. Nickel-Titanium alloys are also known as Nitinol®.
8. Nickel-Molybdenum Alloys
Nickel-Molybdenum alloys have excellent resistance to corrosion and oxidation at high temperatures. They also maintain their mechanical properties at high temperatures. A common nickel-molybdenum alloy is also known as Hastelloy®. This nickel alloy is often used in heat exchangers, pumps, and reactor pressure vessels.