Synthesis and lapping performance of a detonation nanodiamonds slurry by a SPS deagglomeration technology

In order to obtain a simple and efficient technique to prepare detonation nanodiamonds (DNDs) lapping slurry, deagglomerate DND powders by a spark plasma sintering (SPS) technology was proposed in the present study. The effect of SPS treatment temperature on the surface characteristics and dispersion properties of DND powders in deionized water have been studied. The best deagglomeration of DND powders with the peak particle size distribution of 79 nm is achieved for the DND that treated by SPS at 500 °C. The DND dispersed water solution is used as lapping slurry for the four ceramics (Al2O3, AlN, Si3N4, and 3Y-TZP) with different mechanical properties. The material removal rate and surface quality of the four ceramics in lapping process were also examined and compared, in which showed the highest material removal rate for 3Y-TZP and the lowest for Si3N4. The surface roughness of the four ceramics can be decreased to <10 nm by lapping sequentially with slurry of diamond grit size of 3, 0.5, and 0.1 μm and DND slurries successively. Compare to Al2O3 and AlN, 3Y-TZP and Si3N4 ceramics show lower surface roughness. And a lowest roughness of Ra 3.4 nm is achieved for 3Y-TZP. In lapping of AlN ceramic, Al(OH)3 is formed due to the hydrolysis reaction, which is produced shallow pits with the size of grain.