Metal thermal conductivity is measured by thermal conductivity. Thermal conductivity refers to the 1m thick material under stable heat transfer conditions, the temperature difference between the two sides of the surface is 1 degree (K, ℃), within 1 second (1S), the heat transferred through an area of 1 square meter, the unit is Watt/meter·degree (W/(m·K), here K can be replaced by ℃). Different materials have different thermal conductivity. The thermal conductivity of the same substance is related to its structure, density, humidity, temperature, pressure and other factors. When the moisture content of the same substance is low and the temperature is low, the thermal conductivity is small. In general, the thermal conductivity of solids is greater than that of liquids, and that of liquids is greater than that of gases. The thermal conductivity of metals is arranged from large to small: silver, copper, gold, aluminum, sodium, molybdenum, tungsten, zinc, nickel, iron, platinum, tin, lead.