Optimisation of TiN-IBAD coatings for wear reduction and corrosion protection

Hard TIN layer coatings are commonly used as a single layer or sometimes as multilayers in order to improve wear resistance due to their outstanding m echanical characteristics. Usually the corrosion protection by these films is only moderate. Pores and defects can easily be formed in the processing stage, The mechanical properties as well as the porosity can be influenced by ion bombardment during deposition. This contribution has the objective o f studying the correlation between corrosion and mechanical properties of t he TiN layers and TiO2/TiN multilayers on steel (Ck45) produced by ion beam assisted deposition (IBAD) as a function of deposition parameters, The exa mination of the electrochemical phenomena occurring on the surface of the l ayer was based on the current density/potential measurements and on the sca nning electrochemical microelectrode (SEME). Furthermore friction and wear resistance of the layer was determined by pin-on-disk measurements, and str ucture and morphology studied by X-ray diffraction (XRD) and AFM. The most important result was the finding that the degree of crystallinity of the co atings affected directly the hardness and wear resistance. The corrosion pr otection power on the other hand, increased with low crystallinity and high content of amorphous TiO2 or TiN. (C) 1999 Elsevier Science B.V. All right s reserved.