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Desirable properties of heating elements

Short answer

Desirable heating element properties: high resistivity (compact), high melting point, low temperature coefficient (stable power), oxidation resistance at high temperature, mechanical strength and ductility for winding, low cost. Common materials: nichrome (up to 1150°C), Kanthal (up to 1300°C), silicon carbide (up to 1450°C), molybdenum/tungsten (above 1500°C in vacuum/inert gas).

What are the desirable properties of heating elements?

A heating element converts electrical energy into heat by I2RI^2R loss, so its material must withstand high temperature for a long time. The desirable properties are:

  1. High resistivity: a short length of wire gives the required resistance, so the element is compact.
  2. High melting point: it can work at high temperature with a safety margin.
  3. Low temperature coefficient of resistance: resistance (and so power) stays nearly constant from cold to hot.
  4. Free from oxidation at high temperature: oxidation reduces cross-section and causes early burnout.
  5. High mechanical strength and ductility: it can be drawn into wire or strip and wound into coils, and it does not break when heated and cooled repeatedly.
  6. Low cost and easy availability.

Common materials: nichrome (80% Ni, 20% Cr, up to about 1150°C), Kanthal (Fe-Cr-Al, up to about 1300°C), silicon carbide (up to about 1450°C), molybdenum and tungsten (in vacuum or inert gas, above 1500°C).

✓ Answer checked by Claude Opus 5.5 (high effort)

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