Gold electroless deposition

A detailed descriptimi of the gold electroless deposition process may be found in the first original papers." ... 

De Leo M, Pereira FC, Moretto LM, Scopece P, Polizzi S, Ugo P (2007) Towards a better understanding of gold electroless deposition in track-etched templates. Chem Mater 19 5955-5964... 

Saliba, R., Mingotaud, C., Argoul, F. and Ravaine, S. (2001) Electroless deposition of gold films under organized monolayers. 

The pores in a commercially available polycarbonate filtration membrane (Poretics) were used as templates to form the nanotubules (pore diameter = 50 nm pore density = 6 X 10 pores cm thickness = 6 pm). As before, the electrolessly plated Au deposits both on the pore walls and the membrane faces [71]. The gold surface layers on the membrane faces allow us to make electrical contact to the Au nanotubules within the pores. The thickness of the gold layers deposited on the pore walls can be controlled... 

Electroless Deposition of Gold. Okinaka (21) verified the mixed-potential theory for the case of electroless gold deposition. Eigure 8.6 shows that the partial cathodic... 

Diffusion barriers are coatings that serve in that role specifically, protection against undesirable diffusion. One of the best examples is that of a 100- tm-thick electrode-posited copper layer that serves as an effective barrier against the diffusion of carbon. Another example is that of nickel and nickel alloys (notably, electrolessly deposited Ni-P) that block diffusion of copper into and through gold overplate. This is achieved by the deposition of a relatively thin Ni-P layer (less than 1 /mm) between the copper and its overlayer. Naturally, the effectiveness of the diffusion barrier increases with its thickness. Other factors in the effectiveness of a diffusion barrier... 

Hilmi and Luong [25] employed a gold working electrode, formed by electroless deposition onto the chip capillary outlet, for highly sensitive amperometric detection of nitroaromatic explosives [with a detection limit of 24 ppb trinitrotoluene (TNT)]. Analysis of a mixture of four explosives (TNT, 2,4-DNT,... 

More recently, another application of SECM detection in DNA and protein chips and in electrophoresis gels has emerged with different detection principles. Wang et al. [81] labeled single-stranded DNA (ssDNA) with gold nanoparticles. After binding to their complementary strand at the chip surface, silver was electroless deposited at the... 

For decorative purposes especially precious metal finishes frequently are applied to plastics—for example, on buttons. In one process, a layer of copper is deposited on the initial conductive film, then electroless nickel, and lastly gold is deposited by immersion. Precious metals, particularly gold, may be used as an alternative to chromium on top of the conventional thick copper and electroplated nickel system. 

Electroless plating — An autocatalytic process of metal deposition on a substrate by reduction of metal ions from solution without using an external source of electrons. It is promoted by specific reductants, namely formaldehyde, sodium hypophosphide, sodium boro-hydride, dialkylamine borane, and hydrazine. Electroless deposition has been used to produce different metal (e.g., nickel, cobalt, copper, gold, platinum, palladium, silver) and alloy coatings. It can be applied to any type of substrate including non-conductors. Some substrates are intrinsic catalytic for the electroless deposition other can be catalyzed usually by sensibilization followed by Pd nucleation also, in some non-catalytic metallic substrates the electroless process can be induced by an initial application of an appropriate potential pulse. In practical terms, the evaluation of the catalytic activity of a substrate for the electroless deposition of a given metal is... 

Kohli, N., Hassler, B.L., Parthasarathy, L., Richardson, R.J., Ofoli, R.Y., Worden, R.M., Lee, I. (2006). Tethered lipid bilayers on electrolessly deposited gold for bioelectronic applications. Biomacromolecules 7 3327-35. 

The gold nanotube membranes were prepared via the template synthesis [21,22] method by electroless deposition of gold along the pore walls of a polycarbonate template membrane [19,43]. The template was a commercially available filter (Osmonics), 6 p.m thick, with cylindrical 30 nm diameter pores and 6 x 10 pores per square centimeters of membrane surface area. 

The three amplification procedures used with this functionahzed Au-quartz crystal interface consisted of detection first using avidin and biotin-labelled liposomes, secondly using avidin-Au-nanoparticle conjugate and the catalysed electroless deposition of gold, and thirdly avidin-alkaline phosphatase interaction with 5-bromo-4-chloro-3-indolyl phosphate causing the biocatalysed precipitation of the insoluble product on the piezoelectric crystal. The separation of surface treatment outside the QCM cell coupled with... 

Electroless deposition is a process that has been used in practice for centuries. Although not recognized as such, electroless deposition of noble metals, e.g., silver or gold was known to the ancient civilizations. In spite of very slow developments throughout the centuries, significant scientific results have been achieved in the second part of the twentieth century.1 3 The research achievements in the area of electroless deposition have contributed to tremendous applications and developments in various industries. 

Since the appearance of the Brenner s paper27 in 1947, electroless deposition was extensively studied for many industrial applications. The most investigated systems by far include nickel, copper, silver, gold, and related alloys. 

Many electroless deposition processes are very useful for the fabrication of various devices in the electronics industry. Significant importance for the electronics applications have metals such as silver, gold, nickel, copper, cobalt, palladium, and related alloys. All of these mentioned metals can quite simply and successfully be deposited via electroless deposition. 

To find the conditions in which the electroless deposition of gold at Ni-P surfaces with an acceptable appearance and adhesion would be possible, the activation of Ni-P substrates with 10% HC1 solution or a mixture of 0.1 M NH4F and sodium sulfamate was investigated. The results showed that only low phosphorus alloys (P content less than 5 wt%) pretreated with ammonium fluoride/sodium sulfamate mixture can be used for a successful electroless gold plating from cyanide solution and hydrazine as a reducing agent.31... 

In the electroless deposition of gold from noncyanide solutions onto Ni-B and Ni-P surfaces, solutions containing thiosulfate and sulfite were used. The composition of a noncyanide solution for electroless deposition of gold used by Kato et al.32 is presented in Table 2. 

Composition of noncyanide solution for electroless deposition of gold used by Kato et al.32... 

It seems that the solution for electroless deposition of gold with ascorbic acid as a reducing agent developed by Sullivan and Kohl34 and presented in Table 3 produces very uniform coating with excellent adhesion, low porosity, good solderability, and very small crystallite size (about 25 nm).29... 

Electroless deposition can successfully be used in the production of various composite materials useful for the electronics applications. The examples include silver-coated copper or nickel particles, used in screen printing,43 gold-coated nickel powders, silver and/or palladium-coated polymers or glass powders used in ball grid array, etc. 

Gold nanoparticles were electrolessly deposited on the surface of carbon nanotubes from cyanide solution using borohydride as a... 

The formation of elemental gold layer at the surface of conductive polymers has been reported in the literature 92,93 Synthesis of nanostructures and self-assembled palladium nanowires from Pd(II) complexed solutions using hydrazine as a reducing agent were reported by Shi et al.94,95 The process was carried out for 120s at 60°C. Electroless deposition of nanowires of other metals is also possible and quite realistic. However, no particular engineering applications are yet known. 

Asefa, T., and Lennox, R.B. 2005. Synthesis of gold nanoparticles via electroless deposition in SBA-15. Chemistry of Materials 17, 2481-2483. 

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