Liquid Metal TIM properties

Posted by Amanda M. Hartnett

Monday, June 30th, 2008

Liquid Metal shear and mechanical properties (viscosity) demonstrated through basic stencil printing.

Many of my customers are now getting their minds wrapped around the idea of using liquid metals as TIMs. Until they actually have the personal experience of working with it however, they don’t fully grasp what it is like to handle.

The closest thing I am able to compare the indium-gallium liquid metals to is the consistency of mercury. Most of us have had the luxury (although an unfortunate health hazard) to play with mercury broken out of a thermometer as a child. The liquid metals used as thermal interface materials (TIMs) are quite similar in their tendency to coalesce into little balls due to surface tension. Additionally, the viscosity of liquid metal TIMs are nearly identical to mercury.

Viscosity, or the ability to withstand shear, is a very telling property of materials. It is perhaps the most significant property depending on the method of handling and application used for the material. The viscosity of mercury is 1.53 x 10^-3 Pa*s and the liquid metals of the indium gallium system are almost identical.

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