Recommend me a thermal conductive material

[hap2001]

Hi, I'm looking for something like a thermal pad, but more tough. It need to be:

Thermally conductive,
Electrically isolated,
Withstand up to 110 degree C,
Not degrade over several years,
Easy to deform elastically,
Difficult to deform plastically,
Lower hardness than bare silicon die,
Available in sheet form of < 1mm thickness.

A normal thermal pad for computers is almost okay except the mechanical strength, What's your suggestion? Thanks.

[David Hess]

You did not say how high the voltage is.

What about Kapton or mica?

[T3sl4co1l]

What does the joint look like?

Low-modulus (soft elastic) materials are at odds with the "difficult to deform plastically" (implied: high yield strength) requirement.  What do you really need?  What alternatives have you considered in joint design, and why have you gone down a route with a potentially impossible requirement (is this an X-Y problem)?

Tim

[hap2001]

You did not say how high the voltage is.

Less than 30 volts.