In the field of packaging, coatings are commonly applied on containers to avoid interactions between them and their content. For glass bottles, application of a thin film prevents interactions with the phase in contact and consequently the alteration of surface properties of the latter. In this article, we propose an innovative way to apply amorphous alumina coatings on glass bottles by metalorganic chemical vapor deposition from aluminum tri-isopropoxide. A numerical model, using the Computational Fluid Dynamics code FLUENT, has been developed to calculate local profiles of gas flow, temperature, concentration and deposition rates into the reactor. The sub-micrometric alumina films have been deposited at reduced pressure between 480°C and 670°C. Uniform thickness profiles have been determined on cross sections over the length of the bottle and have been successfully simulated. Strongly improved hydrolytic resistance with regard to the uncoated bottles reveals the excellent performance of the films.

We propose a method to apply amorphous alumina films on the inner surface of glass containers aiming to improve their hydrothermal barrier property. We have carried out alumina deposition on Si substrates as a function of deposition temperature to determine the physico‐chemical properties of the thin film materials, and on glass containers to evaluate the influence of post‐deposition hydrothermal ageing on the films properties. Film preparation has been achieved by metal‐organic chemical vapor deposition (MOCVD), using tri‐isopropoxide aluminum (ATI) dissolved in anhydrous cyclohexane as precursor, in a temperature range between 360 °C and 600 °C. A direct liquid injection technology is used to feed the reactor in a controlled and reproducible way. The amorphous alumina films have been characterized by several techniques such as XRD, EPMA, XPS, SEM, AFM and scratch‐test method. Films are amorphous and hydroxylated at 360 and 420 °C and close to stoichiometric at 490 and 560 °C. Hydrothermal ageing simulated by a standard sterilization cycle modifies the adhesion and surface morphology of the alumina film on glass containers to a rough, porous and non‐adhesive layer. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 15772 [ 9 ] radio frequency magnetron sputtering, [ 2 ] atomic layer deposition, [ 10 ] sol-gel, [ 5 ] and metalorganic chemical vapor deposition (MOCVD). [ 7,[11][12][13] CVD is one of the most attractive techniques for the time effi cient deposition of such coatings on complexin-shape geometries with conformal coverage, i.e., uniform thickness along the surface. Composition, stoichiometry, crystallinity, and microstructure of the material can be adjusted by fi ne tuning of the MOCVD experimental parameters such as reactor design, precursor selection, reactive atmosphere, deposition temperature, and pressure. The MOCVD of alumina from vaporized aluminum tri-isopropoxide (ATI) is very well documented. [ 7,8,[11][12][13][14][15][16] ATI yields amorphous and stoichiometric alumina coatings with a smooth and dense microstructure at 5 Torr in the temperature range 420 to 650 °C. [ 7,8,14,15 ] Higher process temperatures lead to the deposition of nanocrystallized γ -Al 2 O 3 [ 15 ] or to the homogeneous decomposition of ATI, which generates a different microstructure. [ 11 ] The ATI molecule is well described in the literature.[ 17 ] It is sensitive to water vapor and thus it is subjected to ageing upon exposure to ambient atmosphere, which results in its partial or total hydrolysis in nonvolatile compounds, Al(O i Pr) 3− n (OH) n ( n = 1, 2) and Al(OH) 3 , respectively. [ 12,17 ] The precursor is usually melted, maintained in supercooled state, and vaporized with a bubbler.Despite the simplicity and the cost effectiveness of this solution, the use of ATI in the supercooled state has two drawbacks. First, maintaining ATI at the vaporization temperature for a long-period impacts the stability of the molecule and subsequently the coating quality. [ 12 ] Second, it is diffi cult to know exactly the mass fl ow rate of the generated reactive gas. Such poorly controlled transport conditions lead to nonreproducible processes, especially for the present case when low activation energy prevails in the entire temperature range of interest, de facto resulting in mass transport limited process. The direct liquid injection (DLI) technology overcomes these drawbacks with the controlled vaporization of the solution made of ATI dissolved in a carrier solvent. [ 18 ] The DLI of ATI is insuffi ciently documented in the literature. Song et al. [ 19 ] and Krumdieck et al. [ 13 ] implemented the technique in a pulsedpressure MOCVD process. The authors used a solution of ATI in n -octane and in dry toluene, respectively. Coatings obtained