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Electrochemical Characterization of Archaeological Tin‐Opacified Lead‐Alkali Glazes and Their Corrosion Processes
Author(s) -
DoménechCarbó A.,
DoménechCarbó M. T.
Publication year - 2005
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200503322
Subject(s) - cassiterite , tin , electrochemistry , materials science , alkali metal , corrosion , metal , redox , metallurgy , electrode , mineralogy , chemistry , organic chemistry
The electrochemical response of weathered and unweathered archaeological tin‐opacified glazes attached to paraffin‐impregnated graphite electrodes is described. Upon comparison with the square wave voltammetric response of SnO 2 , PbO and PbO 2 , Sn‐ and Pb‐centered reduction processes can be characterized. Reduction of Sn(IV) involves the stepwise formation of solid Sn(II) and Sn metal, successively, at potentials of −0.08 and −0.55 V vs. AgCl/Ag. Reduction of network‐modifier Pb(II) in glazes occurs at −0.5 V and is accompanied by the reduction of network‐forming Pb(IV) at potentials ranging from +0.65 to +0.20 V, confirming the presence of such centers in glazes. Voltammetric data suggest the presence of small amounts of Sn(II) resulting from the reduction of cassiterite during the firing process. A series of correlations between the peak currents can be established, indicating that the weathering process obeys a kinetic process rather than a equilibrium‐like situation.