Thermally stable diamond compacts

A diamond compact which is adapted for bonding to metallic matrix material of a surface set or impregnated drill bit, which compact consists essentially of a polycrystalline mass of diamond particles present in an amount of at least 70 percent by volume bonded into a hard conglomerate and being able to withstand a temperature of 1200.degree. C. in a vacuum without any significant structural degradation of the compact occurring, the compact having bonded to a surface thereof an alloy layer, the alloy containing at least 40 percent by weight of silver or gold or a combination thereof and 1 to 10 percent by weight of an active metal selected from the group consisting of tungsten, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium and molybdenum and having a liquidus temperature above 700.degree. C.

A diamond compact adapted for bonding to metallic matrix material of a surface set or impregnated drill bit, which compact consists essentially of a polycrystalline mass of diamond particles present in an amount of at least 70 percent by volume, and a second phase, wherein the polycrystalline mass of diamond particles is bonded into a hard conglomerate able to withstand a temperature of 1200.degree. C. in a vacuum without any significant structural degradation of the compact occurring, the compact having bonded to a surface thereof an alloy layer, the alloy containing at least 40 percent by weight of silver or gold or a combination thereof and 1 to 10 percent by weight of an active metal selected from the group consisting of tungsten, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium and molybdenum and having a liquidus temperature above 700.degree. C.