Division of Laser Technology Applications

In the division of Laser Technology Applications (LTA) pulsed laser deposition of hard composite materials is studied both theoretically and experimentally. The investigations are concentrated on metal borides. Rhenium diboride ReB₂ and tungsten tetraboride WB₄ are one of the most promising candidates for the ultra-incompressible, super-hard materials. Even in the form of thin films they have super-hard properties and in future may become an alternative to other hard coatings. So far in LTA superhard WB₃ films, 1 mm thick, were obtained with hardness 55 – 75 GPa at a load of 5 mN [1]. The targets were prepared from tungsten-boride powder using spark plasma sintering (SPS) method. The deposited films are fairly rough. At present the magnetron technique is being applied in order to get smoother films. In addition the effect of disparate masses of boron and tungsten on parameters of laser-ablated plasma plume is studied theoretically with the aim of better understanding  of the expansion of tungsten borides plasma [2].

Synthesis of single wall carbon nanotubes (SWCNTs) by the laser vaporization method is also studied. For 355 nm laser wavelength, good quality SWCNTs were obtained only at fluence F = 3 J·cm^-2 while for 1064 nm good results were obtained in the fluence range of 1 ≤ F ≤ 6 J·cm^-2 [3].