High-temperature heat exchangers must withstand extreme thermal conditions, corrosion, and mechanical stress. Therefore, the materials used are carefully selected for their thermal stability, oxidation resistance, and mechanical strength. Common materials include:

1. Stainless Steel (e.g., 304, 316, 310, 321)

   • Good corrosion resistance and mechanical strength

   • Suitable for temperatures up to ~800°C (depending on the grade)

2. Inconel (e.g., Inconel 600, 625, 718)

   • A nickel-chromium alloy with excellent resistance to oxidation and creep at temperatures up to ~1000°C

   • Common in aerospace, chemical, and power plant applications

3. Hastelloy

   • Nickel-molybdenum alloys known for corrosion resistance under severe conditions

   • Useful in high-temperature, chemically aggressive environments

4. Titanium and Titanium Alloys

   • Excellent corrosion resistance, moderate high-temperature performance (~600°C)

   • Often used in heat exchangers exposed to seawater or aggressive chemicals

5. Ceramics (e.g., Silicon Carbide, Alumina)

   • Extremely high temperature resistance (>1200°C)

   • Brittle, but ideal for specialized high-temp gas heat exchangers

6. Carbon Steel

   • Cost-effective and strong, but less resistant to corrosion and oxidation

   • Typically used in applications below ~425°C

7. Aluminum Oxide-Coated Metals

   • Coatings help extend the temperature range and protect from oxidation