Nanostructured surfaces 

Annealing influence in vacuum on dispersion of molybdenum nanofilms deposited onto non-metallic materials 
Yu.V. Naidich1, I.I. Gab1, T.V. Stetsyuk1, B. D. Kostyuk1, D.B. Shakhnin2, 
О. M. Fesenko3
1Frantsevich Institute for Materials Science Problems of NASU
3 Krzhyzhanovskogo St., Kyiv 03680, Ukraine
E-mail: gab@ipms.kiev.ua
2University "Ukraine" 
23 Lvivska St., 03115 Kyiv, Ukraine
3Institute of Physics of NASU 
46 Nauky ave., Kyiv, 03680, Ukraine

The kinetics of dispersion during annealing within the temperature range 1200  1600 °C for various exposition times in a vacuum was studied for molybdenum nanofilms 100 nm thick deposited onto oxide (quartz glass, leucosapphire, alumina ceramic) and non-oxide (silicon and aluminum nitrides, glassy carbon, silicon carbide single crystals) non-metallic materials.
It was found that initially continual molybdenum films deposited onto all the materials studied remained unchanged even after short-term annealing (2 ± 5 min) at 1200 °C.
It was established that the most stable one of films deposited onto oxide materials is a film onto an alumina ceramic, which, even after 20 minutes of annealing at 1600 °C, covers about 50% of the substrate area. The least resistant one is film onto a quartz glass which beginning to disperse and interact with the substrate surface already at 1300 °C.
Among the films deposited onto non-oxide materials, the film onto a silicon nitride surface was the least resistant and it began intensively disperse and interact with the substrate material already at 1300 °C. The most resistant one is a film onto an aluminum nitride, which, even after 20 minutes of annealing at 1500 °C, covered more than 60% of the substrate surface area.
Based on the results of these studies, kinetic curves for the dispersion of molybdenum films during annealing were built, on the basis of which it is possible to develop processing modes for brazing the investigated nonmetallic materials metallized with molybdenum.