Wyniki wyszukiwania - Biblioteka Nauki

1

Structure and properties of ceramic preforms based on Al2O3 particles

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Dobrzański L. A. , Kremzer M. , Nagel A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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tom Vol. 35, nr 1

7-13

EN

Purpose: The main goal of this project is to elaborate and optimize the method of manufacturing the porous, ceramic preforms based on Al2O3 particles used as the reinforcement in order to produce modern metal matrix composites by pressure infiltration method with liquid metal alloys. Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of Al2O3 powder with addition of pore forming agent. The preform material consists of powder Alcoa Al2O3 CL 2500, however, as the forming factor of the structure of canals and pores inside the ceramic, agglomerated framework the carbon fibres Sigrafil C10 M250 UNS were used. The addition of carbon fibres was 30, 40 and 50% of weight. The TGA analysis of carbon fibres has been made. The investigations of the structure of powder Al2O3 Alcoa CL 2500, the used carbon fibres and the obtained ceramic preforms on the scanning electron microscope (SEM) have been made. The measurement of permeability of the obtained materials on the specially designed station has also been made. Findings: The obtained preforms are characterized by volumetric participation of ceramic phase of 15-31%, what is the result of differential addition of the pores forming agent, and the high permeability indicates on “the open porosity”. Research limitations/implications: The basic limit of the mentioned method is the possibility of obtaining preforms of porosity less than 85%, where in case of using the ceramic fibres the pores can be more than 90% of material volumetric. Practical implications: The manufactured ceramic preforms are widely used as the reinforcement to produce the composite materials by the infiltration method. That method allows manufacturing the metal elements locally reinforced and the near-net shape composite products. Originality/value: The received results show the possibility of obtaining the new preforms being the cheaper alternative for semi-finished products based on the ceramic fibres and the use of carbon fibres as the pores forming agent indicate that it is the high-quality process.

2

Aluminium matrix composites fabricated by infiltration method

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Dobrzański L. A. , Kremzer M. , Nowak A. , Nagel A.

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2009

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tom Vol. 36, nr 1

5-11

EN

Purpose: The aim of this work is to examine the structure and properties of metal matrix composites obtained by infiltration method of porous ceramic preforms by liquid aluminium alloy. Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of ceramic powder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the pore forming the carbon fibers Sigrafil C10 M250 UNS were used. Then ceramic preforms were infiltrated with liquid eutectic EN AC - AlSi12 aluminum alloy. Stereological and structure investigations of obtained composite materials were made on light microscope. The mechanical properties of obtained composite material were investigated in tensile strength test and hardness test. Findings: It was proved that developed technology of manufacturing of composite materials based on the porous ceramic Al2O3 preforms infiltrated by liquid aluminium alloy ensures expected structure and strength Hardness increased about twice compared to the matrix and this process can be used in practice. Practical implications: The presented metal matrix composites fabrication technology allows to obtain locally reinforced elements and near net shape products. Originality/value: Results show the possibility of obtaining the new aluminium matrix composite materials being the cheaper alternative for other materials based on the ceramic fibers.

3

Defective apoptosis of U937 cells induced by benzyl isothiocyanate (BITC)

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Stasilojc G. , Nagel A. , Koszalka P. , Bigda J. J.

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nr 4

4

Fabrication of ceramic preforms based on Al2O3 CL 2500 powder

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Dobrzański L. A. , Kremzer M. , Nagel A. , Huchler B.

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tom Vol. 18, nr 1-2

71--74

EN

Purpose: The aim of a work is to elaborate the method of manufacturing the porous, ceramic preforms based on Al2O3 particles used as the reinforcement in order to produce modern metal matrix composite materials. Design/methodology/approach: Semi-finished products were manufactured by the method of sintering of ceramic powder. The preform material consists of powder Condea Al2O3 Cl 2500, however, as the forming factor of the structure of canals and pores inside the ceramic, agglomerated framework the carbon fibres Sigrafil C10 M250 UNS were used. The investigations of the structure of powder Al2O3 Condea Cl 2500, the used carbon fibres and the obtained ceramic preforms on the scanning electron microscope (SEM) have been made. The measurement of permeability of the obtained materials on the specially designed station has also been made. Findings: The obtained preforms are characterised by volumetric participation of ceramic phase of 15 - 31%, what is the result of differential addition of the pores forming factor, and the high permeability indicates on “the open porosity”. Research limitations/implications: The basic limit of the mentioned method is the possibility of obtaining preforms of porosity less than 85%, where in case of using the ceramic fibres the pores can be more than 90% of material volumetric. Practical implications: The manufactured ceramic preforms are widely used as the reinforcement to produce the composite materials by the method of infiltration. That method allows manufacturing the metal elements locally reinforced and the near-net shape composite products. Originality/value: The received results show the possibility of obtaining the new preforms being the cheaper alternative for semi-finished products based on the ceramic fibres and the use of carbon fibres as the pores forming agent indicate that it is the high-quality process.

5

Aluminium matrix composites fabricated by pressure infiltration process

100%

Dobrzański L. A. , Kremzer M. , Gołombek K. , Nagel A.

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tom Vol. 28, nr 3-4

520-523

EN

The paper presents the method of manufacturing of modern aluminium matrix composites reinforced by ceramic particles. Material for experiments was made using the pressure infiltration of the ceramic preforms with the liquid aluminium alloy. Ceramic preforms were manufactured by the method of sintering of ceramic powder with the addition of pores forming agent in the form of carbon fibres Sigrafil CIO M250 UNS of Company SGL Carbon Group. The EN AC - AlSil2 alloy features the matrix material, whereas the A1203 Condea CL 2500 powder was used as the reinforcement. The ceramic preforms were coated with the Ni-P alloy to improve the wettability of AI2O3 particles. Metallographic examinations were made on the light microscope and on the scanning electron microscope (SEM) of the preforms structure and of the structures of the obtained composite materials. The obtained results indicate to the possibility of obtaining new materials with all advantageous properties of the particular composite constituents by infiltration of the ceramics with the liquid aluminium alloy.

PL

W pracy została przedstawiona metoda wytwarzania nowoczesny materiałów kompozytowych a osnowie aluminiowej wzmacnianych cząstkami ceramicznymi. Materiał do badań wytworzono na drodze infiltracji ciśnieniowej porowatych preform ceramicznych ciekłym stopem aluminium. Ceramiczne preformy wytworzono metodą spiekania proszku ceramicznego z dodatkiem kształtującym strukturę porów w postaci włókien węglowych Sigrafil CIO M250 UNS o charakterystykach zestawionych w tabeli 3. Odlewniczy stop aluminium EN AC -AlSil2, którego skład chemiczny przedstawiono w tabeli 1 stanowił osnowę, natomiast jako wzmocnienia użyto proszku A1203 Condea CL 2500. Własności użytego proszku ceramicznego zestawiono w tabeli 2. Preformy ceramiczne zostały pokryte stopem Ni-P w celu poprawy zwilżalności cząstek AI2O3. Pokrycie wewnętrznych powierzchni porowatych szkieletów spiekanych umożliwiło urządzenie służące do przepompowywania przez nie odczynników użytych w procesie nanoszenia powłok przedstawione na rys. 1. Wykonano badania metalograficzne w mikroskopie świetlnym i elektronowym mikroskopie skaningowym celem zbadania struktury preform ceramicznych (rys. 2) i otrzymanych na ich bazie materiałów kompozytowych ( rys. 3 i 4). Otrzymane wyniki wskazują na możliwość uzyskania metodą infiltracji ceramiki ciekłym stopem aluminium nowych materiałowo własnościach łączących pozytywne cechy składników kompozytu.

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The translational aspect of CTCs aggressive phenotype in breast cancer patients

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Topa J. , Markiewicz A. , Nagel A. , Szade J. , Majewska H. , Skokowski J. , Seroczynska B. , Welnicka-Jaskiewicz M. , Zaczek A. J.

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nr S2