Differences in Thermal and Electrical Conductivity among Pure Titanium, Copper, and Stainless Steel
1. Thermal Conductivity
Copper: It is a benchmark for high thermal conductivity among common metals. The thermal conductivity of pure copper at room temperature is approximately 401 W/(m·K). This excellent thermal transfer capability makes it widely used in heat exchangers, radiator tubes, and electronic device heat sinks, as it can rapidly dissipate or transfer heat.
Stainless Steel: Its thermal conductivity is much lower than that of copper. Taking 304 stainless steel (the most commonly used grade) as an example, its thermal conductivity at room temperature is only about 16.2 W/(m·K), roughly 4% of pure copper's thermal conductivity. The low thermal conductivity is due to the alloying elements (such as chromium and nickel) in stainless steel, which disrupt the regular arrangement of atoms and impede heat transfer via lattice vibrations and free electrons. This property makes stainless steel suitable for applications requiring thermal insulation or slow heat transfer, like kitchen cookware handles and high-temperature structural components in some industrial equipment.
Pure Titanium: Its thermal conductivity is between copper and stainless steel but is still far lower than copper. At room temperature, the thermal conductivity of pure titanium is around 21.9 W/(m·K), about 5.5% of pure copper's and slightly higher than that of 304 stainless steel. The relatively low thermal conductivity of titanium is related to its hexagonal close-packed (HCP) crystal structure, which restricts the movement of heat carriers. This characteristic allows pure titanium to be applied in scenarios where moderate thermal insulation and structural stability are needed, such as aerospace engine components and chemical industry heat exchange equipment.
2. Electrical Conductivity
Copper: Pure copper has extremely high electrical conductivity, with an electrical conductivity of approximately 58 MS/m (megasiemens per meter) at room temperature, second only to silver among metals. Its free electron density is high and electron mobility is strong, so it is the first choice for manufacturing wires, cables, and electrical contact components, ensuring low energy loss during current transmission.
Stainless Steel: Its electrical conductivity is very poor. The electrical conductivity of 304 stainless steel is only about 0.9 MS/m at room temperature, less than 2% of pure copper's. The addition of chromium, nickel, and other alloying elements introduces a large number of lattice defects and electron scattering centers in the material, which significantly hinders the flow of free electrons. This low electrical conductivity makes stainless steel an ideal material for electrical shielding and anti-static structural parts in some cases.
Pure Titanium: Its electrical conductivity is also much lower than that of copper, with a room-temperature electrical conductivity of around 2.3 MS/m, about 4% of pure copper's and higher than that of 304 stainless steel. The limited electrical conductivity of titanium is caused by the scattering effect of its crystal structure on electrons. In engineering, pure titanium is rarely used for conductive components; instead, it is valued for its corrosion resistance and high strength-to-weight ratio in non-conductive structural applications.
