Consolidation of diamond packed powders

Claim 1

A process for preparing diamond composite structures comprising: (1) cold pressing an intimate mixture of transparent diamond powder and fine opaque nondiamond carbon powder to form a green body having a thickness of from more than zero to about 4000 microns wherein the nondiamond carbon powder is present in an amount to fill the interstices between the diamond particles; (2) forming a polycrystalline diamond coating over all the surfaces of the green body; (3) directing a pulse of lased light at one of the two large faces of the green body to quickly melt the nondiamond carbon powder in a given area before substantial heat is lost to the diamond powder in that area; (4) allowing the carbon melt to cool and grow homoepitaxially from the surfaces of the diamond particles and form polycrystalline diamond; and (5) repeating steps (3) and (4) until essentially all the nondiamond carbon powder up to a depth of about 2000 mcirons has been converted into polycrystalline diamond which bonds the diamond particles together; (6) wherein if the green body has a thickness of from more than 2000 microns to about 4000 microns, step (3), (4), and (5) are repeated by directing the lased light at the opposite large face of the green body.