Papers by Author: R. Sitek

Abstract: The paper presents results of investigations into the structure and corrosion resistance of Ti-Al diffusion layers produced on two phase (a+b) Ti6Al4V alloy by Chemical Vapour Deposition (CVD). The process was carried out in aluminium chloride (AlCl3) mixed with argon atmosphere. Surface topography and microstructure characterization of the coatings were examined by scanning electron microscopy (SEM). The local chemical composition witch 1 μm lateral resolution was measured via EDS. The phase content was investigated by X-ray diffraction and analysis of the chemical composition of the surface by XPS. Corrosion resistance was tested using the potentiodynamic method in 0.1M Na2SO4 and 0.1M H2SO4 solutions at the room temperature. Their resistance to high temperature at atmospheric pressure was tested by 24-hours cycling to 700°C. The results indicate that the layers produced on the Ti6Al4V titanium alloy exhibit a very good adhesion combined with exceptional corrosion resistance, especially high at high temperatures.

Abstract: The paper presents the results of investigations into the structure and properties of Ni-Al diffusion layers produced on INCONEL 100 by Chemical Vapour Deposition (CVD). The process was carried out in aluminium chloride (AlCl3) mixed with hydrogen atmosphere. The as-deposited layers were subjected to thermal treatment in vacuum to optimize their adhesion, hardness and temperature-resistance. Microstructural characterization of the coatings was carried out by scanning electron microscopy (SEM) The chemical composition was measured via EDS and the phase content was investigated by X-ray diffraction XRD. The resistance to high temperature of the coatings at atmospheric pressure was tested by applying 24-hours cycles at 950 °C. Scratch-tests provided data on the microhardness and adhesion of the coatings. The results indicate that the layers produced on the INCONEL 100 exhibit a very good adhesion combined with exceptional corrosion resistance at high temperatures.

Abstract: The paper presents the use of trimethylaluminum in PACVD method to obtain the surface layers like alumina or aluminum nitride on Inconel nickel alloy. The glow discharge nitriding at a temperature of 750°C leads to the formation of aluminum oxynitride in the layer, whereas annealing in argon plasma at a temperature of 1050°C – to the formation of nickel and aluminum based intermetallic phases of the NiAl or Ni3Al type with aluminum oxide present within the outer zone of the coating. The presence of the surface layer of the Al2O3+NiAl+Ni3Al type formed on nickel alloys may be significant from the point of view of the applications that require a high heat resistance.