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Cylindrical shape samples of AISI 420 martensitic stainless steel were nitrided by cathodic cage plasma nitriding technique at temperatures of 623, 673 and 773 K for 5 h. In this technique the samples are placed on an insulating plate inside a cage that shields the cathodic potential. A systematic study was made to test the efficiency of this technique, when compared with conventional ionic nitriding, related to the elimination of defects such as edge effect. The process present a bigger nitriding rate and the samples nitrided using this new technique displayed crystalline phases and hardness comparable with those obtained using conventional ionic nitriding. Moreover, it was possible to eliminate completely the erosion rings often present in conventionally ionic nitrided samples due to edger effects.

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AISI 409 ferritic stainless steel samples were nitrided using the cathodic cage plasma nitriding technique (CCPN), with the addition of methane to reduce chromium precipitation, increase hardness and wear resistance and reduce the presence of nitrides when compared to plasma carbonitriding. Microhardness profiles and X-Ray analysis confirm the formation of a very hard layer containing mainly ε-Fe 3 N and expanded ferrite phases.

This research used the "cathodic cage (CC)" technique for TiO 2 film deposition on duplex stainless steel substrate. This technique uses a multiple hollow cathode effect. Duplex stainless steel substrates were treated at temperatures of 300 o C, 350 o C and 400 o C, giving a temperature value ratio (T s /T m ) of 0.27 to 0.31 (Ts being the substrate temperature and Tm the melting temperature of the deposited material). Treatment times of 1, 2 and 4 hours were administered and polycrystalline TiO 2 films were obtained. The films were analyzed by optical microscopy (OM), X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). During analysis, the formation of uniform films and the possibility of controlling the TiO 2 phase were observed. It was also shown that with longer treatment times and higher temperatures the rutile phase predominates. For treatment times of 4 hours at all temperatures, the rutile structure was present. With treatment times of less than 4 hours, anatase was present. In addition, results showed that this simple, low cost technique can be an alternative method for depositions of TiO 2 films, with the advantage of high levels of control over porosity, thickness and phase composition (anatase and rutile).