Vapour Deposition: Thermal Characterization and Application of Metal Oxide Thin Films

Three precursors of group 11 metals, gold(I) 1,3-diisopropyl-imidazolidin-2-ylidene hexamethyldisilazide, gold(I) tert-butyl-imino-2,2-dimethylpyrrolidinate, silver(I) tertbutyl-imino-2,2-dimethylpyrrolidinate were subjected to solution based NMR thermolysis studies. Rates of decomposition and order of reactivity were gathered. Two novel antimony compounds, trimethyl phosphine antimony (III) chloride and bistrimethyl phosphine antimony (III) chloride were subjected to thermal characterization by TGA and CVD experiments in attempt to produce antimony or antimony oxide films. Few experiments gave varying depositions but reproducible coatings were not achieved. Protective coatings of alumina and bilayers of alumina and titania were deposited on bronze test tokens as well as on numismatic silver coins. Multiple tests examined the efficacy of such films against physical and chemical wear. Silver coins were compared to a traditional lacquer coating. The ALD coatings on tokens provided improved wear and chemical protection vs. unprotected coins. Final numismatic coatings of alumina gave greatest adhesion, but did reveal small areas of chemical penetration.