Nickel-based alloys refer to a class of alloys that exhibit high strength and certain oxidation and corrosion resistance at high temperatures ranging from 650°C to 1000°C. Based on their primary properties, they are further categorized into nickel-based heat-resistant alloys, nickel-based corrosion-resistant alloys, nickel-based wear-resistant alloys, nickel-based precision alloys, and nickel-based shape memory alloys. High-temperature alloys are classified based on their matrix into iron-based high-temperature alloys, nickel-based high-temperature alloys, and cobalt-based high-temperature alloys. Among these, nickel-based high-temperature alloys are commonly referred to as nickel-based alloys.

The primary alloying elements are copper, chromium, and molybdenum. They exhibit excellent comprehensive properties and can withstand various acid corrosion and stress corrosion. The earliest application (produced in the United States in 1905) was nickel-copper (Ni-Cu) alloy, also known as Monel alloy (Ni 70 Cu30); Additionally, there are nickel-chromium (Ni-Cr) alloys (which are nickel-based heat-resistant alloys and heat-resistant corrosion-resistant alloys within the corrosion-resistant alloy category), nickel-molybdenum (Ni-Mo) alloys (primarily referring to the Hastelloy B series), and nickel-chromium-molybdenum (Ni-Cr-Mo) alloys (primarily referring to the Hastelloy C series), among others. Meanwhile, pure nickel is also a typical representative of nickel-based corrosion-resistant alloys. These nickel-based corrosion-resistant alloys are primarily used in the manufacture of components for various corrosion-resistant environments in industries such as petroleum, chemicals, and power generation.