What are the three main classifications of high-temperature alloys?

They are categorized into iron-based, nickel-based and cobalt-based alloys by base metal. Iron-based types have low cost for medium-temperature working conditions below 750°C. Nickel-based alloys dominate the market, working steadily at 800–1000°C for aero-engine hot components. Cobalt-based alloys excel at thermal shock and wear resistance yet carry much higher raw material costs, mostly used for industrial gas turbine nozzles and high-temperature molds.