Study of some gilded film/glass interfaces and of one standard type of “liquid gold” XVI ICF TECHNICAL EXCHANGE CONFERENCE 9 th -12 th October 2004 Karlovy Vary Evelyne Darque-Ceretti, Doriane Hélary, Virginie Deram Ecole des Mines de Paris Centre de Mise en Forme des Matériaux UMR CNRS 7635 Sophia-Antipolis France

XIV Technical Exchange Conference Waterford, Ireland October 12 th – 14 th 2002 Annette Lukas/ Ceramic Colour Division Heraeus Germany Composition of precious metal preparations

Introduction Thin gilded films from organo-metallic solutions are used to decorate glass objects Organo-metallic solution = “liquid gold ” Objectives: 1.Analysis of interactions after firing between gold and glass, (treated or no) 2. Characterization of another type of “liquid gold” before and during firing

Part 1: Gilded film /glass Specimen Characterization methods Surfaces observation Interfacial reactions Conclusions

Specimen soda-lime glass untreated or treated with a Ti oxide film (~ 6 nm thick) or a Sn oxide film (~ 8 nm thick) - organometallic preparation with 12 % of metallic Au + small metal additions (Rh, Ag, V, Zr …) - deposition on the substrate and firing in air at ~ 600°C during 15 min ~ µm thick Substrates Gold films

Characterisation methods - Why use them ? Scanning Electron Microscope (SEM) morphology (SE mode) and atomic contrast (BSE mode) of the specimen surfaces Secondary Ion Mass Spectrometry (SIMS) Depth distribution of elements (C, Au, Ti, Si, …) with great sensitivity but problems due to charge effects in the glass substrate Glow Discharge Optical Emission Spectrometry (GDOES) with radio frequency Depth distribution for all elements without charge effects

SEM surfaces observation ä Non continuous gold distribution ä Formation of an agglomerated structure BSE mode SE mode ä Rough surface Ra ~ 0.4 µm For all specimen surfaces : Sn treated glass Firing temperature 600°C

Interfacial reactions Glass substrate Intermediate zone Film ~ 0.2 µm 197 Au (*50) 12 C (*1000) 28 Si (*100) 107 Ag (*1000) 120 Sn (*1000) Charge effects SIMS analysis : In negative secondary mode Sn treated glass - Gold diffusion into the substrates - Tin diffusion preferentially into the gilded film - Contamination by hydrocarbons (C) - Silicon diffusion to the surface

Interfacial reactions Distribution of Au diffused into Sn or Ti treated or untreated glass at 600°C Fitting by the second Fick’s law : Au diffusion until 0.15 µm Quite the same D Au for Ti or Sn pre-treated glass at 600 °C : D Au  treated glass  cm 2 /s Ti pre-treated D Au  untreated glass  cm 2 /s Au diffusion until 0.75 µm 0 1 0,000,030,050,080,100,130,150,180,200,230,25 Distance from interlayer/glass interface (µm) Normalised intensity Ti,Sn Gold diffuses faster into untreated glass Intermediate oxide layer = diffusion barrier Au diffusion until 0.15 µm

Ti treated glass Glass substrate Film ~ 0.2 µm Intermediate zone - Migration of alkali constituents of the base glass in the film with segregation at the extreme surface - Gold diffusion into the substrates -Titanium diffusion preferentially into the gilded film - Contamination by hydrocarbons (H) - Oxidation of the gilded layer (due to the thermal treatment in air) Na Ca/2 Ti Au*2 K*2 Film ~ 0.2 µm Intermediate zone Glass substrate Rf-GDOES analysis : Interfacial reactions

Conclusions - For (600°C) faster Au diffusion into untreated glass D Au  cm 2 /s than pre-treated glass D Au  cm 2 /s Ti and Sn interlayers act as a diffusion barrier - Ti and Sn diffusion into the gold film and into the glass formation of compounds Au-Ti or Au-Sn ? - Diffusion of alkali components from the glass into the gold film formation of compounds ? - Substantial presence of O in the gilded zone formation of a gold oxide ?

Part 2: Characterization of a “liquid-gold” Specimen In-situ observations and analyses during the heating process Conclusions

Our liquid gold Solid resin in situ analytical methods Optical microscope, X-ray diffraction, and thermal methods (differential scanning calorimeter and gravimetric analysis) Sequential methods Scanning electron microscope, energy dispersive spectrometry FTIR spectroscopy 500  m

1 mm 25°C 1 mm 25°C 1 mm 65°C 1 mm 65°C 1 mm 350°C 1 mm 350°C 1 mm 450°C 1 mm 450°C 1 mm 600°C 1 mm 600°C 1 mm 200°C 1 mm 200°C Optical Microscope + Thermo-Gravimetric Analysis Metallic film formation smoothing, spreading Drying phase Evaporation of the solvent mix Thermal decomposition of the resinates

Reflectance FTIR  25°C - 150°C : Loss of hydrocarbons  150°C - 330°C :  C=O vibration Decomposition of R-SO 2 -OR' groups  Above 350°C : Thin film formation C-H vibration C=O vibration R-SO 2 -OR' groups Transmittance

300°C  650°C  FWHM Increase of gold crystallite size 300°C Crystalline gold Amorphous resins X-Ray diffraction

Complementary analysis : EDS Surface analysis after firing HEATING Liquid gold after screen-printing Thickness  50  m 600°C : Heterogeneous film Thickness  150 nm

Conclusions - Critical temperature 300°C Existence of the first gold crystallites - From 300°C to 600°C, Gold recrystallisation and grain growth Oxidation or decomposition of some componds :V,Rh? Smoothing and spreading of the film Interdiffusion of gold into the glass and alkali elements into the gilded film (part 1) What is the effect on adhesion properties?