AN INTERFACE STUDY OF VARIOUS PVD TIN COATINGS ON PLASMA-NITRIDED AUSTENITIC STAINLESS-STEEL AISI 304

The adhesion between a TiN coating and a plasma-nitrided austenitic st ainless steel is influenced by using different process steps. In order to obtain some information about the effects of various parameters, d ifferent process steps are used during the coating of austenitic stain less steel AISI 304. The deposition of a TiN layer with a Ti intermedi ate layer results in bad adhesion, especially when a thicker TiN coati ng has been deposited. X-Ray diffraction measurements indicate the pre sence of a martensitic phase on top of the plasma-nitrided surface aft er deposition of the TiN coating. This martensitic phase is also obser ved if after plasma nitriding only an additional heat treatment is car ried out. A transmission electron microscopy study is also performed t o reveal the microstructure.