Thermal tape is one form of thermal adhesive that's used frequently between a heatsink and a computer circuit, typically chosen if the heat sink doesn't have a heat-sink retention mechanism to keep it in place permanently. Thermal tape works like a rubber band because it has two "rings" that form a thermal contact. When the ring is pressed on a certain conductive material, a current runs through the conductive material. The amount of current depends on the strength of the adhesive and the thickness of the thermal tape. Because this thermal contact is non-permanent, heat shrink materials may be applied to the ring and the circuit, which force the adhesive back onto the sheet metal surface. Thermal tape works best with smaller, closer-fitting connections and is less expensive than other forms of thermal adhesive.
The typical thermal tape product comes in rolls similar to a large cross-word paper and has an open-ended ring at one end. You use the thermal tape to adhere to the heat sink or copper plate (the "hot" surface), and the sheet-metal ends have an optional peel-and-stick backing. Since thermal tapes are meant to be applied to a relatively tight surface, there are several different shapes and sizes of thermal tapes, and the sheets vary in both size and flexibility.
The thermal tape has several uses, but the most common one is between heatsinks. The tapes provide a very convenient means of directly adhering moisture to the copper pad, without needing to use solder. Heat sinks rely on a sheet-metal sleeve to stop air from passing through, which means that without the heat sink, the sheet metal may warp or bend when exposed to high heat. Thermal tapes allow the sheet to be opened while the heat sink is in place to provide a clean, unobstructed connection.
Another popular application of thermal tape products is between CPU pads. Thermal tape compounds are used in a variety of applications in computer science, such as mating the printed circuit board to the CPU's copper surface, which provides for a more stable and secure fit. CPU pads also use thermal tape to provide for a stable connection between the motherboard and the CPU. Motherboards often use a tab or channel that allows the motherboard to slide into the CPU's channel. The thermal tape prevents damage to the motherboard by preventing it from mating with the CPU and helps provide for a tighter fit.
The potential applications of the thermal adhesive compounds are virtually endless. When properly applied, it can create a barrier between two heated elements, such as two heat sinks or liquid cooling loops. It can also prevent damage from thermal radiation by acting as a radiant barrier, slowing the transfer of heat up and down, which prevents components from over-heating. And it can also act as a cushioning agent, helping to prevent component failure due to thermal shock.
