AVS 46th International Symposium
    Vacuum Metallurgy Division Tuesday Sessions
       Session VM+TF-TuM

Paper VM+TF-TuM7
A Study of the Mechanical Behaviour of Plasma Deposited Silica Films on Polycarbonate and Steel

Tuesday, October 26, 1999, 10:20 am, Room 620

Session: Ionized Plasma and Chemical Vapor Deposition
Presenter: B. Drévillon, CNRS, Ecole Polytechnique, France
Authors: A. Hofrichter, CNRS, Ecole Polytechnique, France
A. Constantinescu, CNRS, Ecole Polytechnique, France
S. Benayoun, E.N.S.A.M, France
P. Bulkin, CNRS, Ecole Polytechnique, France
B. Drévillon, CNRS, Ecole Polytechnique, France
Correspondent: Click to Email
The deposition of silica for protective coatings on polymers is of increasing interest for various applications. Key issues in the mechanical behaviour of the film are the properties of the film-substrate interface that can be modified by different pretreatments. The objective of this work is to estimate the constitutive behaviour of the film and the interface by a serie of mechanical experiments and computer simulations. In order to gain a better understanding of the involved phenomena a comparison between depositions on polycarbonate and stainless steel have been performed. The films are deposited in a low pressure (1 mTorr), scaleable integrated distributed microwave 2.45 GHz electron cyclotron resonance (IDECR) reactor, which allows fast deposition at room temperature of dense, stoechiometric silica. The internal stress of the films was evaluated with profilometry and their Young modulus measured by the vibrating slab technique. Microscratch as well as nano-, micro- and Vickers indentation tests were performed on polycarbonate and steel samples for different thickness and processing powers. As indentation measurements can not be interpreted directly, the tests have been simulated by finite elements using the Castem2000 code (CEA-France). The simulated indentation curves and the final shape of the indent were compared to the measurements. The obtained stress and strain distribution in the film conducts to a reasonable explanation of the crack system observed on the indented surfaces. Finally a parametric study of the influence of the material parameters of the interlayer on the global mechanical behaviour will also be presented.