Further Applications and Perspectives

A multitude of potential further applications opens up to nanodiamond materials in a variety of technological areas. Examples hitherto described include, among others, the preparation of field emitters for display uses. Current research focuses, for instance, on utilizing the lattice defects and the resulting fluorescence as weU as the unpaired spins. More applications are expected to emerge in the field of scratch-resistant transparent coatings. Moreover, it should be possible to realize 

Nanodiamond consists of particles showing a size in the range of nanometers. A distinction has to be made between materials containing very small particles (d 4nm) on the one hand and larger nanodiamond particles on the other. Very small particles tend toward agglomerate formation, which is favored by the presence of graphitic carbon as well as by the functional groups situated on the particle surface. The preparation can be achieved in different ways (Box 5.1) 

By detonation A mixture of explosives with a negative oxygen balance is detonated inside a closed container. Due to the prevailing conditions, the resulting soot contains a large portion of nanoscopic diamond particles. These are purified by treatment with concentrated mineral acids that remove both metallic and graphitic impurities. 

By shock synthesis A carbon material is converted into diamond by the action of a shock wave generated, for example, by a detonation or a projectile. This procedure is employed, for instance, to prepare polycrystalline microdiamond with primary particles measuring in the range of nanometers. 

Nanoscale diamond can further be generated by milling of larger diamond particles or by a transformation of other forms of carbon that is induced by irradiation or heating. 

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