Up-scaling the production of modified a-C:H coatings in the framework of plasma polymerization processes

• Published in: Solid state sciences 2009-10, Vol.11 (10), p.1768-1772
• Main Authors: Corbella, C., Bialuch, I., Kleinschmidt, M., Bewilogua, K.
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Coating properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Modified a-C:H; PACVD; Physics; Plasma polymerization; Up-scaling
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/j.solidstatesciences.2008.11.010

Hydrogenated amorphous carbon (a-C:H) films with silicon and oxygen additions, which exhibit mechanical, tribological and wetting properties adequate for protective coating performance, have been synthesized at room temperature in a small- (0.1 m 3) and a large-scale (1 m 3) coaters by low-pressure Plasma-Activated Chemical Vapour Deposition (PACVD). Hence, a-C:H:Si and a-C:H:Si:O coatings were produced in atmospheres of tetramethylsilane (TMS) and hexamethyldisiloxane (HMDSO), respectively, excited either by radiofrequency (RF – small scale) or by pulsed-DC power (large scale). Argon was employed as a carrier gas to stabilize the glow discharge. Several series of 2–5 μm thick coatings have been prepared at different mass deposition rates, R m, by varying total gas flow, F, and input power, W. Arrhenius-type plots of R m/ F vs. ( W/ F) −1 show linear behaviours for both plasma reactors, as expected for plasma polymerization processes at moderated energies. The calculation of apparent activation energy, E a, in each series permitted us to define the regimes of energy-deficient and monomer-deficient PACVD processes as a function of the key parameter W/ F. Moreover, surface properties of the modified a-C:H coatings, such as contact angle, abrasive wear rate and hardness, appear also correlated to this parameter. This work shows an efficient methodology to scale up PACVD processes from small, lab-scale plasma machines to industrial plants by the unique evaluation of macroscopic parameters of deposition. [Display omitted]