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A Study on Morphology, Structure and Properties of Silver and Gold Coatings Applied by a Chemical Reduction Deposition Method Using Double-Spray Device

Bakhshizadeh, Ali | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52754 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Dolati, Abolghasem
  7. Abstract:
  8. Silver and gold are precious, expensive metals and are used in various applications, such as jewellery and ornamentals, electronics and optics. In the present study, soda-lime glass surfaces firstly were activated with acidic stannous chloride solution. Then, silver and gold were coated on these surfaces via simultaneous spraying of two solution: A silver- or gold-complex bearing solution and a reducing agent (Dextrose for Ag and H2O2 for Au) bearing solution. For silver coating, the effect of various parameters such as time, reducing agent concentration, number of passes, presence and concentration of Urotrpin and Decamethylcyclopentasiloxane (DMCPS) as microstructural modifiers and brighteners, and temperature on the deposition rate was investigated. For gold coating, the effect of pH, Au concentration, time and presence of Urotropin as an additive on growth and deposition rate was explored. The deposition rates for silver and gold coating were 40 and 25 nm/min, respectively and both coatings showed parabolic behaviour in weight gain. Urotropin was a promising additive that reduced the deposition rate by 15-25%, but yielded a noticeably smoother (average surface roughness = 17.87 nm for silver and 23.86 nm for gold), brighter surface with smaller particle size for both silver (30-70 nm) and gold (< 50 nm). Finally, UV-Visible Spectroscopy was performed to determine the transmission/absorption characteristics of silver and gold coatings. The lowest absorption for silver coating was in the range λ = 310-390 nm, while for gold coating this range was shifted to λ = 450-570
  9. Keywords:
  10. Silver Nitrate ; Hydrogen Peroxide ; Spray ; Microstructure ; Optical Properties ; Tetrachloric Acid ; Dextrose

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