Sintered diamond compacts with a cobalt binder.

Diamond powder can be successfully cemented with cobalt. At 62 kilobars the sintering occurs over the temperature range from 1570 degrees to 1610 degrees C. The maximum microhardness of the compact ( 3000 kilograms per square millimeter on the Knoop scale) is obtained with a mixture of 20 percent cobalt (by volume) and a diamond particle size of 1 to 5 micrometers.