STUDY ON A PLASMA FOCUS APPLICATION: EFFECT ON NITRIDED OR CARBURIZED AUSTENITIC STAINLESS STEEL OF ENERGETIC LIGHT IONS BOMBARDMENT

J. GARCÍA MOLLEJA; MILANESE M.; NIEDBALDSKI J; L. NOSEI; J. FERRÓN; J. M. BURGI; SUPÁN J; GUICHÓN S.; FEUGEAS J.

Mar Del Plata

Workshop; Latin American Workshop On Plasma Physics 2011; 2011

LAWPP

An experimental study is made in order of knowing the behaviour of austenitic stainless steel, which we previously nitrided or carburized, under the impact of energetic pulses of ions and plasma. Austenitic stainless steel has good mechanical properties and excellentcorrosion resistance. This type of steel (AISI 316L in our case) can improve its hardness and wear resistance by using ion nitriding or ion carburizing. The crystalline structure is modified by a cold plasma treatment which causes the formation of a new phase called expandedaustenite, formed by means of the diffusional processes triggered on the steel surface. These processes are well known but a complete characterization was never reached. In this work we nitrided austenitic steel AISI316L samples using a 80 % hydrogen - 20 % nitrogeno atmosphere at 5 mbar and a temperature of 400 C. Ion carburization has been made, too. In this case we used the same working parameters and a mixture of 50 % Ar - 45 % H - 5 % CH . After that, we studied this expanded austenitic phase under energetic ion 2 4bombardment with a dense plasma focus device, with an energy of 2 kJ. The vacuum chamber was filled with low mass gases, 1.6 mbar deuterium or helium or 2.4 mbar of hydrogen. The respective sample was located at 82 mm from the anode. The number of pulses (1, 5,and 10) gradually modifies the crystalline structure of nitrided or carburized samples. A characterization of the samples was made with a Reichert optical metallographic microscope. Crystalline structure was determined by means of GIXRD (Grazing Incidence X-RayDiffraction), comparing structure modification with different gas and number of pulses. Vickers microhardness was used to know surface hardness before and after the treatment.