Nickel-based alloys refer to a class of alloys that exhibit high strength and certain resistance to oxidation and corrosion, among other comprehensive properties, at high temperatures ranging from 650 to 1000°C. Based on their primary properties, they are subdivided into nickel-based high-temperature alloys, nickel-based corrosion-resistant alloys, nickel-based wear-resistant alloys, nickel-based precision alloys, and nickel-based shape memory alloys.

1. Nickel-Based High-Temperature Alloys

The primary alloying elements include chromium, tungsten, molybdenum, cobalt, aluminum, titanium, boron, and zirconium. Among these, chromium provides resistance to oxidation and corrosion, while the other elements serve to strengthen the alloy. They exhibit high strength and excellent resistance to oxidation and gas corrosion at temperatures ranging from 650 to 1000°C. This class of alloys is the most widely used among high-temperature alloys and offers the highest high-temperature strength. They are primarily used in the manufacture of high-temperature components for aircraft engine blades, rocket engines, nuclear reactors, and energy conversion equipment.

2. Nickel-Based Corrosion-Resistant Alloys

The primary alloying elements are copper, chromium, and molybdenum. These alloys possess excellent overall performance and can withstand various forms of acid corrosion and stress corrosion. The earliest application was the nickel-copper alloy, also known as Monel; other examples include nickel-chromium alloys, nickel-molybdenum alloys, and nickel-chromium-molybdenum alloys. They are used to manufacture various corrosion-resistant components.

3. Nickel-Based Wear-Resistant Alloys

The primary alloying elements are chromium, molybdenum, and tungsten, with small amounts of niobium, tantalum, and indium. In addition to their wear resistance, these alloys also exhibit good oxidation resistance, corrosion resistance, and weldability. They can be used to manufacture wear-resistant components or serve as cladding materials, applied to the surfaces of other substrate materials through hard-facing and thermal spraying processes.

4. Nickel-Based Precision Alloys

These include nickel-based soft magnetic alloys, nickel-based precision resistance alloys, and nickel-based electric heating alloys. The most commonly used soft magnetic alloy is permalloy, which contains approximately 80% nickel. It features high maximum and initial magnetic permeability, as well as low coercive force, making it an important core material in the electronics industry. The primary alloying elements in nickel-based precision resistance alloys are chromium, aluminum, and copper. These alloys possess high resistivity, a low temperature coefficient of resistivity, and good corrosion resistance, and are used to manufacture resistors. Nickel-based electric heating alloys are nickel alloys containing 20% chromium; they exhibit good oxidation and corrosion resistance and can be used continuously at temperatures ranging from 1000 to 1100°C.

5. Nickel-Based Shape Memory Alloys

These are nickel alloys containing 50 (at)% titanium. Their recovery temperature is 70°C, and they exhibit excellent shape memory properties. By slightly altering the nickel-titanium composition ratio, the recovery temperature can be adjusted within the range of 30–100°C. They are primarily used in the manufacture of self-deploying structural components for spacecraft, self-actuating fasteners for the aerospace industry, and artificial heart motors for biomedical applications.

Application Areas of Nickel-Based Alloys

The nickel-based alloy industry is experiencing steady growth. Nickel-based alloys with varying compositions and properties are finding increasingly widespread applications as industry develops. Their primary application areas include:

1. Marine: Marine structures in coastal environments, seawater desalination, marine aquaculture, and seawater heat exchange.

2. Environmental Protection: Flue gas desulfurization systems for thermal power generation and wastewater treatment.

3. Energy: Nuclear power generation, comprehensive utilization of coal, and tidal power generation.

4. Petrochemical Industry: Oil refining and chemical processing equipment.

5. Food Industry: Salt production and soy sauce brewing.