Abrasion-resistant coatings for thermal interfaces
A system having a removable electronic component employs an abrasion-resistant thermally conductive film as a thermal interface between the removable electronic component and a heat sink. The abrasion-resistant film reduces thermal impedance between the removable electronic component and the heat sink when the removable electronic component is repeatedly installed and removed from a chamber in a host device. The abrasion-resistant film includes a polymer formed from a silicone-containing resin and an inorganic particulate filler; the film may also be interlocked with a corrosion protection layer at the heat sink. A method of forming a heat sink is provided that minimizes increases in thermal impedance.
1 . A system, comprising:
a host device including a frame defining a chamber;
a removable module that generates heat which is transferable to a first surface of the module, the module being removably installable in the chamber;
a heat sink associated with the frame to dissipate the heat from the first surface, wherein the heat sink includes a second surface having a corrosion protection layer including at least one of a trivalent chromium and a hexavalent chromium; and
a thermally conductive film including a silicone elastomer and thermally conductive inorganic particulate filler dispersed in the silicone elastomer at a concentration of between 25 and 50 phr, wherein the thermally conductive film is applied to the second surface such that the silicone elastomer is interlocked with the corrosion protection layer, and wherein the thermally conductive film makes direct contact with the first surface when the module is installed in the device to permit the heat to be received from the first surface.
2 . The system of claim 1 wherein the inorganic particulate filler has an average particle size of about 3 μm and comprises at least one of graphene, fullerene, and graphite.
3 . The system of claim 1 wherein the inorganic particulate filler is selected from the group of aluminum oxide, zinc oxide, magnesium oxide, aluminum nitride, boron nitride, silicon dioxide, diamond, clay, aluminosilicate, and combinations thereof.
4 . The system of claim 1 wherein the thickness of the substrate is between about 10-100 μm.
5 . The system of claim 1 wherein the thermally conductive film is less than about 25 μm thick.
6 . The system of claim 1 wherein the thermally conductive film reduces thermal impedance of a region of contact between the heat sink and the first surface.
7 . A method for forming the heat sink of the system according to claim 1 , comprising:
providing a metal substrate with a first surface;
treating the first surface with a conversion agent to form the corrosion protection layer;
preparing a precursor having a silicon-containing resin and inorganic particulate filler;
coating the precursor onto the corrosion protection layer and curing in situ to polymerize the precursor,
wherein a silicon-containing polymer formed from the resin interlocks with the corrosion protection layer.
8 . The method of claim 7 wherein the conversion agent includes at least one of a hexavalent chromium, and a trivalent chromium.
9 . The method of claim 7 , including coating the precursor onto the corrosion protection layer by screen printing, slot coating, dip coating, selective printing, or a combination thereof.
10 . The method of claim 8 wherein the silicon-containing polymer is less than about 25 μm thick.
11 . The method of claim 7 wherein the inorganic particulate filler is present at a concentration of less than or equal to 50 phr.