Patent ID: 8322398

Claim:
A process for producing an aluminum-diamond composite, comprising: (a) preparing a diamond powder comprising diamond grains having a grain size of at least 50 μm at 50% or more by volume of all diamond grains and diamond grains having a grain size of at most 15 μm at 10 to 40% by volume of all diamond grains; (b) adding to said diamond powder a colloidal silica at 0.5 to 3% by mass in terms of solid content with respect to all diamond grains to obtain a slurry; (c) press forming or slip casting said slurry to produce a compact of said diamond grains; (d) firing said compact at 800° C. to 1100° C. in air or in a nitrogen atmosphere to obtain a porous diamond preform wherein the content of the diamond grains is 40 to 70% by volume of the total volume; (e) heating said porous diamond preform; (f) heating an aluminum alloy to a temperature equal to or above the melting point of the alloy and impregnating said porous diamond preform with the alloy to produce a plate-shaped aluminum-diamond composite wherein both surfaces are covered by a surface layer comprising a metal mainly composed of aluminum; and (g) working said aluminum-diamond composite into an aluminum-diamond composite.