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Depozice uhlíkových nanotrubek metodou depozice z plynné fáze s asistencí plazmatu
Jašek, O. ; Eliáš, M. ; Zajíčková, L. ; Kučerová, Z. ; Kudrle, V. ; Matějková, Jiřina ; Rek, Antonín ; Buršík, Jiří
Carbon nanotube properties provoked interest in many fields of application but there is still need to develop deposition techniques, which enable precise control of nanotubes positioning, alignment and properties. Chemical vapor deposition (CVD) methods and lately also plasma enhanced CVD (PECVD) are most promising to reach this goal. In the first part of the article we will briefly describe carbon nanotubes structure and properties and review the necessary conditions and possible control mechanisms used in PECVD deposition method. In the second part, examples of two deposition techniques, one working at a low pressure and one at an atmospheric pressure, will be described and reached results analyzed.
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Nanocrystalline diamond films deposition by PECVD in ASTEX type microwave reactor
Jašek, O. ; Karásková, M. ; Buršíková, V. ; Zajíčková, L. ; Franta, D. ; Frgala, Z. ; Matějková, Jiřina ; Rek, Antonín ; Klapetek, P. ; Buršík, Jiří
Nanocrystalline diamond film was deposited by microwave CVD in the ASTeX type reactor on a mirror polished (111) oriented n-doped silicon substrate. The deposition mixture consisted of 9 pct of methane in hydrogen. The applied microwave power (2.45 GHz)and pressure were 850 W and 7.5 kPa, respectively. The substrate temperature was 1 090 K. The diamond nucleation process was enhanced by rf induced dc selfbias of -125 V. The film exhibited very low roughness (rms of heights 9.1 nm). Its hardness and elastic modules were 70 and 375 GPa, respectively. The optical constants were determined by combination of spectroscopic ellipsometry and reflectometry employing the Rayleigh-Rice theory for the roughness and the dispersion model of optical constants based on the parameterization of densities of states. The deposition rate was 57 nm/min including the 5 min nucleation step.
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On the redistribution of aluminium and carbon in the weld joints of steels in the temperature range 500-1100oC (1,15 wt.% Al)
Stránský, K. ; Million, Bořivoj ; Foret, R. ; Michalička, Petr ; Rek, A.
Measurements of Al, Cr, Fe, Ni, C redistribution in welded joints of unalloyed 12050+1,15Al steel and high alloyed Cr-Ni steel in temperature range 500-1100oC were realised by means of analytical complex JEOL JXA 8600/KEVEX. The C, Al, Cr, Fe, Ni diffusion coefficients were established and the relation among diffusion coefficients were discused.
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Simultaneous diffusion of aluminium, carbon, chromium, iron and nickel in steel weldments at temperature interval 500 to 1100°C
Stránský, K. ; Million, Bořivoj ; Foret, R. ; Rek, A. ; Michalička, Petr
In this paper results of measurements of simultaneous diffusion of aluminium, carbon, chromium, iron and nickel in welded joints of unalloyed 12050+Al steel and high alloy austenitic chromium-nickel steel are presented.
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