Magnetron deposition of a-C:ND coatings by nanodiamond transfer: pulse number impact on aggregation and graphitization

The possibilities of the synthesis of nanodiamond/amorphous carbon composite structures (a-C:ND) by the pulsed mode of direct current magnetron sputtering are analyzed in the current paper. We showed that the ion-induced microarcing on the substrate surface caused the transfer of nanodiamond particles of an average size of 4.5 nm, whose size distribution is close to one of the precursor particles. According to the structural investigations carried out by transmission electron microscopy, electron diffraction, Raman spectroscopy and electron energy loss spectroscopy, the coatings with uniformly distributed nanodiamond inclusions can be obtained at a low number of discharge pulses. The particles transferred at 10 pulses preserve their luminescence properties and become encapsulated in the sp 3 -rich carbon matrix. However, with a higher number of pulses, graphitization and agglomeration of the particles induced by microarcing and ion irradiation are observed.