Selective encapsulation of the carbides of yttrium and titanium into carbon nanoclusters

Characterization of the arc-discharge deposits at the cathode from anodes containing yttrium oxide and titanium by transmission electron microscopy and x-ray diffraction shows different results with respect to an encapsulation of the metal carbides into carbon clusters. Yttrium carbide is encapsulated into carbon nanoclusters in a crystalline phase. The formation of titanium carbide, on the other hand, preempts the formation of the carbon—carbon bonds necessary to form the carbon cages, so that only titanium carbide clusters are observed. Thermodynamic data support the interpretation of the results.