INTERFACE STUDY OF PHYSICALLY VAPOR-DEPOSITED TIN COATINGS ON PLASMA-NITRIDED TOOL STEEL SURFACES WITH AUGER-ELECTRON SPECTROSCOPY, RESONANT NUCLEAR-REACTION ANALYSIS AND RUTHERFORD BACKSCATTERING SPECTROSCOPY

Abstract

It is known that adhesion of a TiN coating on a plasma-nitrided tool steel surface depends strongly on the kind of substrate material and on the process steps between plasma nitriding and deposition of TiN. To obtain relevant information concerning the interface composition a combined Auger electron spectroscopy (AES), resonant nuclear reaction analysis (RNRA) and Rutherford backscattering spectroscopy (RBS) analysis has been performed. With these techniques, mutually complementary information could be obtained by measuring quantitative nitrogen (RNRA) and qualitative nitrogen, titanium and iron depth profiles (AES). The composition of the interface between the TiN coating and the plasma-nitrided surface was deduced from both AES and RBS results. The results indicate that the transition treatment carried out between plasma nitriding and TiN coating influences the interface composition. They will be explained in relation to previous adhesion results. The work was carried out on high speed steel ASP 23 and on cold-worked steel 1.2379.