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The article discusses selected aspects of vacuum brazing of joints in fuel, hydraulic and pneumatic systems of modern aero engines. The effect of surface roughness, as well as that of temperature and time of brazing on the flow properties of AgCu42Ni2 and Au-18Ni brazing alloys on the 18-8 austenitic grade steel is discussed. The morphology of steel- filler alloy-steel joints is analyzed. Phenomena taking place during the displacement of the front interface of the filler alloy in gaps of varied width are discussed.

Thermo-chemical treatment of austenitic stainless steels has recently been increasingly developed with the aim to improve the frictional wear resistance of the steels without spoiling their high corrosion resistance. Prospective lines of this development are processes conducted under glow discharge conditions, such as nitriding at temperatures below 500°C, nitriding combined with oxidising, and producing composite layers of the nitrided layer+Ti(NCO) with the use of a Ti(OC3H7)4 vapour-containing atmosphere. The paper presents the results of metallographic examinations and the measurements of the phase composition, corrosion resistance and frictional wear of the surface layers produced using these processes, and also describes the kinetics of the glow discharge assisted nitriding process. The results show an increase of the frictional wear resistance of the steels, whereas their good corrosion resistance is preserved.