A Temperature-Programmed Desorption Technique for Studying Surface Contamination and Acid-Base Properties of Thick Metal Sheets

This paper describes how the temperature-programmed desorption (TDP) technique, which is widely used in the fields of surface science and catalysis, has been newly adapted to investigate the thick metallic sheet samples of about 10cm2 area used in adhesion studies. A high frequency induction system has been designed in order to achieve a high heating rate (up to 200 K.s_1) without creating substantial temperature gradients in the sheet. The sample is placed in a secondary vacuum reactor and the gas desorbed is analysed by means of a quadrupole mass spectrometer. The results presented deal with stainless steel and chromium surfaces, subjected to various chemical treatments. The sensitivity and the resolution of the technique presented are shown to be sufficient to study metallic surface contamination and to characterise the acid sites at the surface by desorption of a basic probe molecule such as ammonia.