Characterization of titanium and titanium nitride coatings obtained with a PIII&D system

M. FAZIO; L. S. VACA; A. MÁRQUEZ

Campinas

Congreso; 23rd Annual Users Meeting (LNLS); 2013

Ti and TiN coatings on stainless steel are proposed to improve the hardness and tribological properties of the surface of this material. Cathodic arc deposition is an efficient technique to produce thin films due to its high deposition rate. In these devices, a high current (100 A) runs between the electrodes generating the emission of a metallic plasma jet from the cathode. When a substrate is located intercepting the plasma jet, a metallic coating is obtained. Applying a pulsed negative bias to the sample, the ion impinging energy on the surface can be increased and if the bias voltage is high ( kV) the ions achieve enough energy to be implanted. When the high negative potential is on ions are accelerated towards the surface and are im- planted, while the bias is on ions condense on the surface resulting in the deposition of a coating or a film. In this way plasma immersion ion implantation is combined with deposition (PIII&D). PIII&D has demonstrated to be useful for the fabrica- tion of nanostructure coatings. The use of high voltage pulses to bias the substrate allows to obtain denser films and to relax internal stress improving the adhesion. The aim of this work was the characterization of Ti and TiN thin films obtained with a PIII&D system. The system was constituted by a dc cathodic arc with a Ti cathode of 5 cm in diameter and an annular copper anode of 8 cm in diameter. The discharge was run continuously at 100 A. The substrate was biased with a pulsed generator. Pulse amplitude was varied from 1 to 15 kV, the pulse rate was fixed at 200 Hz with a pulse duration fo 35 us. Films deposited on stainless steel and silicon substrates with different ion implantation conditions were study at the XRD2 beamline of the LNLS. A theta/2theta geometry similar to Bragg Bentano configuration and grazing incidence were employed. By means of XRR, the film density was determined. The PIII&D technique has not introduced signi¯cant changes in the morphology of the films compared with coatings deposited with a cathodic arc without pulsed bias. However, XRD diffractograms showed clear differences, as shifts in the peak position broadening and splittingof the peaks, indicating that PIII&D has affected the film structure. The lattice parameters and crystallite size were compared among films obtained without and with implantation.