TEM Studies of Nanocarbons and Nanodiamonds (ND): Mechanical milling of ND and Cu

This paper describes the nano-structures of Cu nanocomposites containing 20 and 30 at.% diamond nanoparticles. The Cu nanocomposite powders were fabricated by mechanical milling method and were consolidated by hot extrusion. The solidified sample were thinned to prepare the specimens by focused ion beam technique and the specimens were examined by TEM and EDS. The micro-structural observation showed that the homogeneous distribution of diamond nanoparticles in the Cu nanocomposite could be achieved in 20 at.% diamond content, and that the nanocomposite with homogeneous distribution of diamond nanoparticles has ultra-fine grain structure of approximately 50 nm in diameter. TEM observation revealed the existence of single-digit nano-sized flakes of Fe/Cr in ND aggregates for the first time. The flakes were assigned as contamination from the stainless-steel balls during MM procedure. This finding revealed a possibility of ultra-fine abrasion by the single-digit nano-diamond.