IN-SITU AND EX-SITU MONITORING OF ELECTROCHEMICAL DEPOSITION OF SILVER USING QUARTZ-CRYSTAL RESONATORS

Electrochemical deposition of silver from a 1 mM AgNO3 aqueous acidic solution at 20 mu A cm(-2) was monitored by means of in-situ quartz cr ystal impedance (QCI) technique, in-situ quartz crystal microbalance ( QCM) technique, ex-situ QCI technique and atomic absorption spectrosco py. However, the mass evaluated from the data obtained in the in-situ QCI and QCM measurements on the basis of Sauerbrey equation deviated f rom intrinsic mass of the deposited silver because of a low deposition efficiency, liquid viscously or rigidly coupled with the resonator an d/or stress generated in the deposited layer. Thus one must pay attent ion to these factors when one calibrates a quartz crystal microbalance on the basis of electrochemical deposition of a metal. In-situ QCI me thod utilizing a network analyzer is shown to be a powerful technique for simultaneous and qualitative monitoring of mass and surface struct ure changes. For the quantitative mass measurements, the mass sensitiv ity must be calibrated using another direct method such as atomic abso rption spectroscopy.