Thermal Paste Round-up: 85 Products Tested
Not All Thermal Pastes Are Alike
Because thermal paste is a high-margin product, the market is crowded. While the exact composition of most solutions is a well-kept secret, a Google search makes it pretty easy to get a list of typical ingredients. The upper temperature limit is typically 150°C, though some pastes claim to withstand up to 300°C or more.
The composition of a paste determines its thermal conductivity, its electrical conductivity, its viscosity, and its durability. But what is a paste really made of? Basic compounds consist of zinc oxide and silicone as a binding agent. However, such simple combinations are barely sold anymore. Most vendors start with these ingredients and add other materials, like aluminum. Case in point, the Prolimatech PK1 sports 60-85% aluminum content, 15-25% zinc oxide, and 12-20% silicone oil, as well as an anti-oxidation agent. Some ingredient lists are more mysterious. For instance, the one printed on be quiet!‘s DC 1 syringe ambiguously specifies 60% metal oxide, 30% zinc oxide (wait a second; since when is zinc not a metal?), and 10% silicone.