Papers by Author: Wojciech Starosta

Abstract: The plasma beams were generated in a Rod Plasma Injector (RPI) operated in the Deposition by Pulsed Erosion (DPE) and Pulse Implantation Doping (DPE) modes. Samples of unalloyed and austenitic stainless steels were irradiated with short (μs scale) intense (energy density 2.0-5.0 J/cm²) pulses. The near surface layer - thickness in μm range - was melted and simultaneously doped with active element like nitrogen, cerium and lanthanum. Heating and cooling processes were of non-equilibrium type. The most important obtained results were: (i) austenitic structure was present in unalloyed steels after HIPPB modification processes and (ii) modified surface layers of austenitic stainless steel showed significant improvement of tribological properties and increase of high temperature oxidation resistance as compared with initial material.

Abstract: Austenitic stainless steels with their very good corrosion resistance are used in industrial applications nuclear and petrochemical industries, pulp and paper chemical, food and chemical processing, biomedical industries and others. But poor tribological and mechanical properties of austenitic stainless steels limit their applications in engineering fields. AISI 316L steel was subjected to transient treatment using high intensity pulsed plasma beams HIPPB. The plasma pulses contained both ions/atoms of electrodes material: Ce, La or (Ce+La) and those of working gas. The pulse energy densities (3.0 J/cm²) were sufficient to melt the near surface layer of steel and introduce REE to the melted material. Heating and cooling processes were of non-equilibrium type.

Abstract: Addition of some active elements such as yttrium, cerium, lanthanum and other rare earths elements (REE) to austenitic stainless steels helps to improve their high temperature oxidation resistance and tribological properties. The high intensity plasma pulses were used to introduce Ce and La into AISI 316L austenitic stainless steel. The plasma pulses contained both ions/atoms of Ce-La and those of the working gas. The pulse energy densities were sufficient to melt the near surface layer of the steel and introduce those elements into the surface layer. Scanning electron microscopy (SEM) as well as energy dispersion spectroscopy (EDS) was used during each one part of surface characterisation. Obtained results allowed us to make decision about directions of modified material successive investigations.