Light-metal alloy-containing thermal pastes

A crosslinkable, heat-conducting silicone composition (Y), comprising:

• wherein 5-60% by volume of a crosslinkable silicone composition (S);
• wherein 40-95% by volume of at least one thermally conductive filler (Z) having a thermal conductivity of at least 5 W/mK;
• wherein the crosslinkable, heat-conducting silicone composition (Y) has a thermal conductivity of at least 0.6 W/mK;
• wherein at least 20% by volume of metallic light metal alloy particles are present as thermally conductive fillers (Z) that fulfill the following features:
• a) wherein their median diameter x50 is in the range of 25-150 μm,
• b) wherein they are produced in the last production step by a melting process and have a predominantly rounded surface shape, and
• c) wherein their distribution range SPAN ((x90−x10)/x50) is at least 0.40;
• and
• wherein the metallic light metal alloy particles contain, as main constituent, at least 60% by weight of a light metal or of a light semimetal selected from B, C, S, P, Be, Mg, Ca, Al and Si.

A process for producing a crosslinkable, heat-conducting silicone composition (Y), comprising:

• providing 5-60% by volume of a crosslinkable silicone composition (S);
• providing 40-95% by volume of at least one thermally conductive filler (Z) having a thermal conductivity of at least 5 W/mK;
• wherein the crosslinkable, heat-conducting silicone composition (Y) has a thermal conductivity of at least 0.6 W/mK;
• wherein at least 20% by volume of metallic light metal alloy particles are present as thermally conductive fillers (Z) that fulfill the following features:
• a) wherein their median diameter x50 is in the range of 25-150 μm,
• b) wherein they are produced in the last production step by a melting process and have a predominantly rounded surface shape, and
• c) wherein their distribution range SPAN ((x90−x10)/x50) is at least 0.40;
• wherein the metallic light metal alloy particles contain, as main constituent, at least 60% by weight of a light metal or of a light semimetal selected from B, C, S, P, Be, Mg, Ca, Al and Si;
• and
• mixing the individual components together