Influence of Argon and Nitrogen Admixture in HMDSO/O₂ Plasmas onto Powder Formation

Abstract

In situ Fourier transform infrared spectroscopy was used to study the powder formation of hexamethyldisiloxane/O2 plasmas. The spectra show that oxygen plays an important role at the beginning of the process. A large amount of oxygen is responsible for intense powder formation. The admixture of inert or non‐reactant gases, such as Ar or N2, into the plasma promotes polymerization of the monomer. The formation of the particulates, the evolution of their size, and chemical characteristics give evidence of a multistep growth process. The size, as well as the production rate, undergoes a reduction once the Ar or N2 amount is increased in the plasma admixture.

Improvement of the Corrosion Resistance of Carbon Steel by Plasma Deposited Thin Films

“…(Rao et al, 2010) (Guruvenket et al, 2010) 806 (Choudhury et al, 2010) (Gengenbach et al, 1999, Scheinmann, 1970) 836 851 Rao et al 2010) (Gengenbach et al, 1999) 956 Ricci et al, 2011, Choudhury et al, 2010 1020, 1130 Gengenbach et al, 1999, Fracassi et al, 2003 1257 (Gengenbach et al, 1999, Choudhury et al, 2010 (Gengenbach et al, 1999) 2961, 2839  C-H CH 3 and CH 2 (Gengenbach et al, 1999, Scheinmann, 1970 3588 Ricci et al, 2011, Choudhury et al, 2010 Table 1. Assignments of the bands in the infrared spectra of the films and their related groups.…”

Corrosion resistance of 2024 aluminum alloy coated with plasma deposited a-C:H:Si:O films

“…With increasing power from 10 to 80 W, the intensity of the band at 1080 cm -1 (Si-O-Si) growths with respect to that at 1030 cm -1 , indicating variations in the SiO x stoichiometry, with x approaching two 23 . There is a rise of news bands lying at 1354 cm -1 (-CH 2 scissors in Si(CH 2 )Si 24,25 ) and 890 cm -1 (-CH 3 rotation in Si(CH 3 ) 2 ) 10 , indicating further fragmentation of the starting organosilicon monomer with increasing P. Furthermore, bands at 3645 cm -1 (OH stretching) assigned to silanol groups 19 develop in the spectra as P is elevated.…”

“…Absorption bands detected in the infrared spectra of plasma-polymerized films from pure HMDSO or using equal proportions of HMDSO and O 2 in the gas mixture. 19 as well as an absorption at 1710 cm -1 associated with the C=O stretching mode 21 . Both contributions were not detected in the spectrum of the film prepared from pure HMDSO since they are not present in the original organosilicon molecule, corroborating the proposal of multiple step reactions in the plasma phase.…”

“…The second one is a regular spherical structure smaller than the first. In general, the concentration of this spherical white spots (region C of Figure 23), composed of silicon, oxygen and carbon and normally observed in organosilicon films deposited from plasmas of HMDSO 19 , increases after film deposition. This kind of structure, formed by polymerization in the plasma phase, is demonstrated to strongly depend on the oxygen proportion in the plasma phase and on the deposition time 32 .…”

“…Figure 3 shows the infrared spectra of films deposited using two different oxygen proportions in the plasma feed: 0 and 50%. The wavenumber of the main absorption bands were collected and identified in Table 1, according to other relevant studies 10,11,[19][20][21][22][23][24][25] . The spectra revealed the presence of asymmetric (2950 cm -1 ) and symmetric (2900 cm -1 ) C-H stretching vibrations.…”