Silver, dissolution

Most electroless silver appHcations are for silvering glass or metallizing record masters. Mirror production is the principal usage for electroless silver. The glass support is cleaned, catalyzed using a two-step catalyst, and coated on one side with an opaque silver film (46). Silver-plated nylon cloth is used as a bacteriostatic wound dressing. A tiny current appHed to the cloth causes slow silver dissolution. The silver acts as a bactericide (47). 

The inhibiting influence of sodium diisobutyldithiophosphinate [385] and 2-mercaptobenzothiazole [386] on silver dissolution in aqueous solutions of pH = 11 has also been investigated. Inhibition was caused by adsorption of both compounds, accompanied with the displacement of cyanides from the silver surface. 

With the lid of the bottle tightly in place, heat the silver composition to 80° C. with mild agitation for a time sufficient to dissolve the silver—dissolution is essentially instantaneous. 

T. P. Hoar (38a) has suggested that the different behavior of ferric and ceric ions in silver dissolution may be considered from a purely electrochemical viewpoint. The anodic and cathodic potentials are very close in the ferric system their polarization curves meet at rather small values of the corrosion current, which does not require that all ferric ion near the metal surface be reduced to ferrous. On the other hand the potential of the ceric-cerous couple is about 0.8 V more noble, and complete reduction at the interface (or complete concentration polarization with respect to ceric ion) is necessary to lower this potential to the value of the Ag-Ag+ couple. 

Studies of passivation layers and corrosion phenomena, particularly with iron and magnesium using EXAFS, NEXAFS and related X-ray absorption spectroscopies have been reviewed elsewhere [589]. Using GIXAFS, depth profiling has become possible and spatially resolved studies of silver dissolution and lithium intercalation have been reported. 

One applies mercury to a silver dissolution in nitrous acid this substance having more relation with this acid, than this acid has with silver, it unites to it and precipitates silver. 

FIGURE 4.5 Plot showing cation and anion concentrations during a kinetic Monte Carlo simulation of silver dissolution with the initial electrolyte concentrations for the anions and cations set at 1M. Reproduced with permission from Policastro et al. [31]. The Electrochemical Society, 2012. 

Li, J. and Wadsworth, M.E. (1993) Electrochemical study of silver dissolution in cyanide solutions. J. Electrochem. 

Figure 11. The effect of the polarization scan rate on the maximum current density of silver dissolution from (1) Agl5Au and (2) Ag20Au alloys in 0.09 MNaNOj +0.001 MHNO3 + 0.01 M AgNOs.

The apparent thickness of the solid-phase diffusion zone calculated according to Eq. (34) with the use of the data of the Table 3 takes values of a few nanometers irrespectively of the alloy composition and the scan rate. A correction for the roughness factor only additionally decreases the 5 value, i.e. 5 A for the whole recording time of a chronovoltammogram. All these facts confirm the idea that, imder the selected polarization conditions, the solid-phase diffusion front in Ag-Au alloys practically follows the siuface rehef of the electrode. For this reason, the diffusion flux and, hence, the partial current density of silver dissolution should be determined by normalizing the current to the true rather than geometric surface area of the electrode. 

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