Barrier SiO2-like coatings for archaeological artefacts preservation

摘要

Thinfilmchemicalvapourdepositiontechniquehasbeenusedformorethan50years.Introducingorgano-siliconesasprecursors,e.g.hexamethyldisiloxane(HMDSO)ortetraethylorthosilicate(TEOS),broughtnewpossibilitiestothismethod.Barrierpropertiesofthinfilmshavebecomeanimportantissue,especiallyforarmyandemergencyservicesaswellasforfoodanddrinkmanufacturers.OurworkisfocusedonprotectiveHMDSOthinfilmsforencapsulatingcleanedarchaeologicalartefacts,preventingthecorrosionfromdestroyingthesehistoricalitems.Thinfilmsaredepositedviaplasmaenhancedchemicalvapourdeposition(PECVD)techniqueusinglowpressurecapacitivelycoupledpasmainflowregime.Oxygentransmissionrate(OTR)measurementwaschosenasthemostimportantoneforcharacterizationofbarrierpropertiesofdepositedthinfilms.LowestOTRreachedfor50nmthinfilmthicknesswas120cm3m-2atm-1day-1.SampleswerealsoanalyzedbyFourierTransformInfraredspectrometry(FTIR)todeterminetheircomposition.Opticalemissionspectraandthinfilmthicknessweremeasuredduringthedepositionprocess.Weoptimizedthedepositionparametersforbarrierlayersbyimplementationofpulsedmodeofplasmaandargonplasmapre-treatmentintotheprocess...