Mechanical behavior and microstructure of nanodiamond-based composite materials

• Published in: Journal of materials science letters 2002-11, Vol.21 (21), p.1699-1702
• Main Authors: Ekimov, E A, Gromnitskaya, E L, Gierlotka, S, Lojkowski, W, Palosz, B, Swiderska-Sroda, A, Kozubowski, J A, Naletov, A M
• Format: Article
• Language: English
• ISSN: 0261-8028
• DOI: 10.1023/A:1020889129195

Nanodiamonds, dynamically synthesized from graphite, represent a promising material for obtaining superhard compacts. Abrasive properties of diamond powders with the nanostructure of grains are better than those of powders of natural and synthetic single crystal diamonds. The high-pressure infiltration of Si into nanodiamond powder resulted in the formation of a 1-2 mm thick composite with the hardness approx =50 GPa. The infiltration process stops because the product of interaction between carbon and silicon, SiC, closes pores. Although the composite thickness (1-2 mm) is suitable for making cutting tools, cylindrical samples with the height and diameter larger than 2-3 and 3-5 mm, respectively, are needed for producing wire drawing dies. The infiltration depth can be increased by the use of diamond powder with a narrow particle size distribution. The absence of small particles filling pores between larger ones leads to the formation of a compact having a higher degree of porosity. In this letter, we describe the process of producing bulk superhard ceramics from SiC and dynamically-synthesized nanodiamonds, as well as their mechanical behavior and microstructure.