A metal TIM is a thermal interface made of indium, indium solder, or a liquid gallium alloy instead of a filled polymer. It wets both surfaces and conducts heat through metal.

Is liquid metal better than indium?

Neither is better in general. Liquid metal can wet surfaces without forming a solid joint, which helps reduce mechanical strain. Indium provides higher bulk thermal conductivity, stays where it is placed, and avoids some containment, aluminum compatibility, and short-circuit risks associated with conductive liquid metals.

Can liquid metal touch an aluminum heat sink?

Liquid gallium should not contact aluminum without a qualified barrier. Gallium can penetrate aluminum along its grain boundaries, so barrier selection and aging validation at the operating temperature are important.

How much temperature does interface resistance cost?

The temperature drop across an interface depends on both heat flux and area-normalized thermal resistance. As heat flux increases, reductions in interface resistance produce larger temperature savings.

Do ASTM D5470 values apply to metal TIMs?

ASTM D5470 can be adapted for metal thermal interface materials, but test conditions must be considered carefully. Clamping pressure, dwell time, surface finish, oxidation, reflow conditions, and metallization can all affect the reported result.