Abstract
Fine and coarse powders of diamond were mixed with Si and sealed in evacuated glass tubes to be HIP'ed at temperatures between 1300°C and 1600°C and at the pressure of 150MPa for 90min. The sintered materials were characterized by means of X-ray powder diffraction, microscope, SEM and EDS. Their densities and mechanical properties were measured. The sintering proceeded rapidly at temperature above 1400°C. The main reaction possibly takes place in the liquid state, because the melting temperature of Si is at 1410°C in air.
The X-ray diffraction patterns were indexed by diamond, Si and SiC. No trace of conversion from diamond to graphite was observed. Among the starting materials prepared, the highest strength was found in the sample whose mixing ratio of fine and coarse diamonds and Si was 1:3:1 in weight. An application of the products to high pressure anvils was attempted and the generation of 7.70GPa in 6-8 split-sphere type apparatus was confirmed.
