Preparation method of composite heat sink

Abstract

A method for fabricating a composite heat sink includes a providing step, a forming step, a pore forming step, and a densification step. The providing step provides a metal substrate, including a top surface and multiple grooves. The forming step uses injection molding to fill the grooves with a mixture and form it on the top surface of the substrate to form a green layer. The mixture includes a binder and a plurality of metal particles. The pore forming step removes the binder from the green layer to form a plurality of pores, resulting in a porous metal layer. The densification step heats the porous metal layer to melt and bond the metal particles, resulting in a dense porous layer with a porosity lower than that of the original porous metal layer. Injection molding integrally forms the green layer on the top surface of the substrate, simplifying the manufacturing process.

Claims

1. A method for preparing a composite heat sink, comprising: a providing step of providing a substrate, the substrate being made of metal, including a top surface and a plurality of grooves formed downward from the top surface, wherein at least a portion of the grooves are obliquely disposed to the top surface; a forming step of filling a mixture into the grooves and forming it on the top surface of the substrate by injection molding to form a preform layer, thereby obtaining a first semi-finished product, wherein... The mixture includes a binder composed of a polymeric material and a plurality of metal particles dispersed in the binder, wherein the binder comprises polyacetal and polyolefin; a pore-forming step, removing at least a portion of the binder from the green layer to form a plurality of pores to obtain a porous metal layer having a first porosity; and a uniform densification step, heating the porous metal layer to fuse at least a portion of the metal particles to obtain a uniformly dense porous layer having a second porosity less than the first porosity.

2. The preparation method as described in claim 1, wherein, Based on a volume of 100 vol% of the mixture, the proportion of the binder is between 30 and 50 vol%.

3. The preparation method as described in claim 1, wherein, The particle size of these metal particles ranges from 8 to 150 micrometers.

4. The preparation method as described in claim 1, wherein, The pore-forming step includes a first step of removing the polyacetal of the green layer through an acidic gas to obtain an intermediate, and a second step of heating the intermediate to the vaporization temperature of the polyolefin to remove the polyolefin to obtain the metal porous layer.

5. The preparation method as described in claim 4, wherein, The adhesive contains at least two polyolefins with different vaporization temperatures. The second step involves a stepped heating process to the vaporization temperatures of the at least two polyolefins to remove them sequentially.

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