Nanodiamonds

Nanometer diamond has the dual properties of diamond and nanometer material. The combination of the two gives nanometer diamond special properties, such as large lattice constant, high specific surface, high chemical activity and low Debye temperature.

Figure 1. The structural units of nanodiamond

Applications:

Nanodiamonds have special morphology, hardness, and particle size, and thus have special photoelectric, magnetic, and thermal properties. Nanodiamonds have certain applications in the fields of ultra-precision polishing, superlubricity, running-in oil, and composite coatings.

• Ultra-precision polishing: For traditional ultra-smooth polishing, the mechanical requirements of the polishing are dominant. If the grinding effect is strong, the grinding disc will change the shape of the polishing die surface. At the same time, it is difficult to guarantee the workpiece surface roughness and surface shape indicators. And obvious scraping grooves and even micro cracks may be formed. The traditional polishing method using very narrowly distributed nanoparticles as abrasives can process ultra-smooth surfaces with a surface roughness of 0.1-1 nm. Most of nanodiamond particles are spherical without sharp angles, and have little cutting effect on workpieces and polishing dies. The thermochemical polishing of nanodiamonds relies on the physical and chemical reaction of nanodiamonds surface and the diffusion of carbon atoms to realize the overall polishing of workpiece surface and eliminate scratches.
• Superlubricity: During the running-in process of internal combustion engine, the lubricating oil with appropriate viscosity makes the friction surface form a sufficiently lubricating oil film, which can not only lubricate and cool the friction surface, but also wash and take away the metal debris dropped during running-in to prevent the friction surface from being scratched. And the quality of the running-in oil directly affects the running-in time and quality of the machine. Utilizing the excellent anti-extreme pressure performance, repair function, and synergistic effect of diamond, as wll as the interaction between lubricating oil additives, composite lubricating oil and additives with excellent friction properties can be developed.
• Composite materials and devices in the electronic field: By combining nanodiamonds with nano-silicon powder, nano-ceramics and various nano-metals, new types of nano-structured materials can be manufactured. Because of their unique properties, they can be used to manufacture semiconductor devices, integrated circuit components and microcomputer parts, etc. In magnetic recording systems with ferromagnetic coatings on magnetic tapes and magnetic disks, nanodiamonds are used as additives in physical deformers for wear reduction, and they can also be used in electrochemical composite films for improving the stability of magnetic recordings.
• Catalyst: Nanodiamond has a large specific surface area, contains various surface functional groups, and has strong activity. Using nanodiamond to formulate a catalyst can improve the reaction activity and promote the interaction of organic compounds.
• Biocarrier: Nanodiamond has a good surface inertness, does not contain heavy metal impurities, and has good compatibility with the human body. It will not cause changes in the structure and performance of biological antibodies, and will not affect their functions. It has been widely used as biocarrier.

References:

1. Frederico R. Baptista, S. A. Belhout, S. Giordani and S. J. Quinn. Recent developments in carbon nanomaterial sensors [J]. Chem. Soc. Rev., 2015, 44, 4433-4453.
2. Xianfeng Chen and Wenjun Zhang. Diamond nanostructures for drug delivery, bioimaging, and biosensing [J]. Chem. Soc. Rev., 2017, 46, 734-760.
3. A. S. Barnard. Predicting the impact of structural diversity on the performance of nanodiamond drug carriers [J]. Nanoscale, 2018, 10, 8893-8910.