SIMULTANEOUS INFRARED REFLECTION-ABSORPTION SPECTROSCOPY AND QUARTZ-CRYSTAL MICROBALANCE MEASUREMENTS FOR IN-SITU STUDIES OF THE METAL ATMOSPHERE INTERFACE/

A new experimental setup for in. situ studies of the metal/atmosphere interface has been developed based on simultaneous infrared reflection absorption spectroscopy (IRAS) and quartz crystal microbalance (QCM) measurements of a metal surface. It consists of an in situ chamber in which the metal can be exposed to a well-controlled atmosphere. Four e xternal devices are connected to the in situ chamber; a Fourier transf orm infrared spectrometer with external optical compartments, a QCM se nsor probe with a frequency counter, a corrosive air generator, and a corrosive air analyzing system. In order to demonstrate the capability of the IRAS/QCM setup, copper was exposed to purified air at 80% rela tive humidity and 25 degrees C. Under these exposure conditions, the i nterface between copper and air consists of cuprous oxide and water ph ysisorbed on the oxide. The kinetics of the cuprous oxide formation co uld be followed in situ with both techniques. The combined IRAS/QCM re sults show excellent agreement with previous combined IRAS and cathodi c reduction measurements and with optical calculations of the IRAS res ponse. Under these conditions, the detection limit in terms of an equi valent Cu2O film thickness is 10 Angstrom for IRAS in situ analysis an d 2 Angstrom for QCM in situ analysis, respectively.