Papers by Author: Stanislaw Gierlotka

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Authors: H. Marciniak, Stanislaw Gierlotka, Bogdan F. Palosz
Authors: Stanislaw Gierlotka, Andrzej Gregorczyk, Bogdan F. Palosz, Ewa Grzanka, Piotr Biczyk, Ulrich Bismayer
Authors: Bogdan F. Palosz, Ewa Grzanka, Svetlana Stelmakh, Stanislaw Gierlotka, Roman Pielaszek, Ulrich Bismayer, H.-P. Weber, Th. Proffen, W. Palosz
Authors: Bogdan F. Palosz, Stanislaw Gierlotka, Ewa Grzanka, K. Akimow, Roman Pielaszek, Piotr Biczyk, A. Grzegorczyk, Svetlana Stelmakh, Ulrich Bismayer, J.F. Janik
Authors: J. Michalski, M.J. Woźniak, K. Konopka, J. Bieliński, Stanislaw Gierlotka, Krzysztof Jan Kurzydlowski
Abstract: An Al2O3/Ni-P composite was formed by hot pressing of alumina powder, coated with chemically plated nano Ni-P. The powders were consolidated at room temperature, 600 and 1000oC. The consolidated specimens were studied by SEM, TEM/HRTM, MFM (magnetic force microscopy) and tested or hardness. It was found that the fabrication method results in a structure of interpenetrating phases of high electric conductivity and that samples consolidated at room temperature and sintered at 600oC retain the nanometric grain size of the metallic phase. Hardness measurements are discussed in terms of the fabrication temperature and structure of the composites.
Authors: Roman Pielaszek, Witold Łojkowski, Stanislaw Gierlotka, Stephen Doyle
Authors: Bogdan F. Palosz, Svetlana Stelmakh, Stanislaw Gierlotka, M. Aloszyna, Roman Pielaszek, P. Zinn, Th. Peun, Ulrich Bismayer, D.G. Keil
Authors: Roman Pielaszek, Svetlana Stelmakh, Stanislaw Gierlotka, Bogdan F. Palosz, Dirk Kurtenbach, Ulrich Bismayer
Authors: J. Michalski, Tomasz Wejrzanowski, Stanislaw Gierlotka, J. Bieliński, K. Konopka, Tomaž Kosmač, Krzysztof Jan Kurzydlowski
Abstract: The fabrication of 3D interpenetrating phases in ceramic-metal composites by high pressure sintering of ceramic powder coated with Ni-P nanoparticles produced by electro-less chemical plating is reported. Electro-less nickel plating resulted in a nano-metric layer of spherical Ni-P nanoparticles of approximately 20-50 nm diameter over the entire surface of the ceramic powder. The coated powders were consolidated by hot pressing (HP) process followed by pressureless sintering after cold isostatic pressing (CIP). SEM, TEM and XRD methods were used to investigate the influence of the consolidation temperature and pressure on the microstructure of composites and particularly the morphology of metallic Ni-P phase. The homogeneity of the interpenetrating network structure was measured by computer image analysis and compared with the results of electric resistance measurements. The results indicate that the use of electroless nickel plating and high pressure consolidation process enables the fabrication of uniform 3D interpenetrating continuous metal-ceramic composites and controlled-density composites possessing a metallic phase of nano- or micro-metre size.
Authors: Grzegorz Kalisz, Ewa Grzanka, Dariusz Wasik, Anna Swiderska-Sroda, Stanislaw Gierlotka, Jolanta Borysiuk, Maria Kaminska, Andrzej Twardowski, Bogdan F. Palosz
Abstract: Nano-composites consisting of a primary matrix phase of hard nanocrystalline SiC and a secondary nanocrystalline GaAs semiconductor phase were obtained by high-pressure zone infiltration. The synthesis occurs in three stages: (i) at room- temperature the SiC nanopowder is compacted under high pressure to 8 GPa, (ii) the temperature is increased to 1240°C, above the melting point of GaAs, and the pores were filled with liquid, (iii) on cooling GaAs nanocrystallites grow in the pores. The synthesis was performed using a toroid-type high-pressure apparatus (IHPP PAS, Warsaw) and a six anvil cubic press (MAX80 at HASYLAB, Hamburg). X-ray diffraction studies were performed with a laboratory D5000 Siemens diffractometer. The phase compositionn, grain size and macrostrains in the synthesized materials were examined. The microstructure of the composites was characterized using a Scanning Electron Microscopy (SEM), and High Resolution Transmission Electron Microscopy (TEM). Far-infrared reflectivity and Raman spectroscopy measurements were used to trace built-in strains.
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