Wyniki wyszukiwania - BazTech

1

Characterization of zirconia composites with nickel particles

Zygmuntowicz J., Miazga A., Łoś J., Konopka K.

Composites Theory and Practice

|

2017

|

R. 17, nr 2

109--113

EN

The aim of this paper was to characterize the microstructure and selected properties of Ni-3YSZ composites. The composites were prepared from a powder mixture containing 90 vol.% ZrO2 and 10 vol.% nickel powder. In the experiments the following powders were used: ZrO2 powder stabilized by 3 mol% Y2O3 from TOSOH ZIRCONIA 3YSZ of an average particle size less than 100 nm and density 6.05 g/cm3 and Ni powder from Sigma-Aldrich of an average particle size 1.5 µm and density 8.9 g/cm3. The samples were formed by uniaxial pressing. Two series of samples were fabricated with different sintering temperatures: series I was sintered at 1400°C and series II was sintered at 1600°C. The sintering process was conducted in an argon atmosphere. The structure of the samples was examined by X-ray diffraction (XRD) after sintering. The microstructure of the composites was investigated by scanning electron microscopy (SEM). The chemical composition was examined by energy-dispersive X-ray spectroscopy (EDS). The selected physical properties of the prepared composites was measured by the Archimedes method. The hardness was measured using Vickers hardness testing. Based on the hardness measurements the KIC values were determined. Uniaxial pressing and the sintering method enabled the manufacture of Ni-3YSZ composites. The microstructure observation revealed homogeneous distribution of the Ni particles in the ZrO2 matrix in both series. The XRD patterns of the composites after sintering at 1400°C (series I) and 1600°C (series II) show that the composites consisted of three phases: t-ZrO2, m-ZrO2 and Ni. It was found that the temperature of 1400°C is not sufficient to obtain Ni-3YSZ composites with a high relative density.

PL

Celem pracy było określenie mikrostruktury i wybranych właściwości kompozytów Ni-3YSZ. Kompozyty wytwarzano z mieszaniny proszku zawierającej: 90% obj. ZrO2 i 10% obj. proszku Ni. W eksperymencie zastosowano następujące proszki: proszek ZrO2 stabilizowany 3% mol Y2O3, firmy TOSOH ZIRCONIA 3YSZ o średniej wielkości cząstek mniejszej niż 100 nm i gęstości 6,05 g/cm3 oraz proszek Ni firmy Sigma-Aldrich o średnim rozmiarze cząstek 1,5 μm i gęstości 8,9 g/cm3. Próbki zostały uformowane w wyniku prasowanie jednoosiowego. Przygotowano dwie serie próbek o różnych temperaturach spiekania: serię I spiekano w temperaturze 1400°C, a serię II spieczono w temperaturze 1600°C. Proces spiekania prowadzono w atmosferze ochronnej argonu. Za pomocą dyfrakcji rentgenowskiej (XRD) określono skład fazowy wytworzonych kompozytów. Mikrostrukturę kompozytów zbadano z wykorzystaniem skaningowej mikroskopii elektronowej (SEM). Skład chemiczny określono za pomocą spektrometru dyspersji energii promieniowania rentgenowskiego (EDS). Wybrane właściwości fizyczne przygotowanych kompozytów zostały zmierzone z użyciem metody Archimedesa. Twardości kompozytów określono metodą Vickersa. Na podstawie pomiarów twardości wyznaczono wartość odporności na kruche pękanie (KIC). Metoda prasowania jednoosiowego pozwoliła na wytwarzanie kompozytów Ni-3YSZ. Obserwacje mikrostruktury ujawniły jednorodne rozmieszczenie cząstek Ni w osnowie ZrO2 w obydwu seriach. Na podstawie analizy fazowej stwierdzono, że wytworzone kompozyty po procesie spiekania w 1400°C (seria I) oraz 1600°C (seria II) charakteryzowały się obecnością trzech faz: t-ZrO2, m-ZrO2 i Ni. Stwierdzono, iż temperatura 1400°C nie wystarcza do uzyskania kompozytów Ni-3YSZ o wysokiej gęstości względnej.

2

ZrO2-Ni composites : properties and characterization

Zygmuntowicz J., Falkowski P., Miazga A., Konopka K.

Composites Theory and Practice

|

2016

|

R. 16, nr 4

249--254

EN

In recent years dynamic progress has been seen in almost all areas of engineering materials. It has contributed to the development of new, innovative materials such as composite materials. Nowadays, a great deal of research is focused on ceramic/metal composites due to their potential to be used in many applications. An example of such a material is ZrO2-Ni composites. This paper describes ZrO2-Ni composites formed by uniaxial pressing and sintering in an argon atmosphere. The microstructure, selected physical and mechanical properties such as hardness, fracture toughness and the biaxial strength of the composites were investigated. The sintered composites had a relative density close to 99% of the theoretical density. The distribution of the component phases was uniform. It was found that the presence of Ni particles affects the mechanical properties of the ZrO2 matrix. It was also revealed that the composites exhibit a lower bending strength than ceramic materials obtained under the same conditions. The composites show a decrease in hardness in regard to the hardness of monolithic ZrO2. The presence of Ni particles in the composites causes dissipation of propagating crack energy, which results in an increased fracture toughness value measured for ZrO2-Ni composites in comparison to the value obtained for monolithic zirconia.

PL

Dynamiczny postęp, jaki miał miejsce w ostatnich latach, widoczny jest praktycznie w każdym obszarze inżynierii materiałowej. Przyczynił się on do opracowania nowych materiałów, takich jak materiały kompozytowe. Obecnie, wiele badań dotyczy kompozytów ceramika/metal ze względu na ich duży potencjał aplikacyjny. Przykładem materiału z tej grupy jest kompozyt ZrO2-Ni. W artykule opisano kompozyty o osnowie tetragonalnego tlenku cyrkonu z dodatkiem niklu formowane na drodze prasowania jednoosiowego oraz spiekane w atmosferze argonu. W pracy opisano mikrostrukturę, wybrane właściwości fizyczne oraz właściwości mechaniczne, takie jak: twardość i odporność na kruche pękanie oraz wytrzymałość mechaniczną na zginanie otrzymanych spieków. Otrzymane spieki charakteryzowały się gęstością względną na poziomie 99% gęstości teoretycznej oraz jednorodnym rozmieszczeniem obu faz w mikrostrukturze kompozytu. W wyniku przeprowadzonych badań stwierdzono wpływ cząstek Ni na właściwości mechanicznych ZrO2. Stwierdzono, że kompozyty wykazują niższą wytrzymałość na zginanie niż materiały ceramiczne uzyskiwane w tych samych warunkach. Kompozyty wykazują spadek twardości w odniesieniu do twardości monolitycznego ZrO2. Obecność Ni w kompozytach prowadzi do rozpraszania energii pęknięcia, co powoduje wzrost wartości odporności na kruche pękanie kompozytów ZrO2-Ni w porównaniu do wartości uzyskanych dla monolitycznego ZrO2.

3

Fabrication methods and heat treatment conditions effect on structure and properties of the gradient tool materials

Dobrzański L., Kloc-Ptaszna A., Pawlyta M., Pakieła W.

Archives of Materials Science and Engineering

|

2012

|

Vol. 56, nr 1

5-21

EN

Purpose: This work concerns manufacturing and research on a new group of the gradient tool materials, manufactured by the conventional powder metallurgy method, consisting in compacting a powder in a closed die and sintering it. Design/methodology/approach: The materials were obtained by mixing the powders of the HS6-5-2 high-speed steel, tungsten carbide (WC). The mixes were poured one after another into the die, yielding layers with the gradually changing volume ratio of carbides within the high-speed steel matrix. Structural research by using the scanning and transmission electron microscopes, x-ray microanalysis and density, hardness and porosity tests, were performed. Structure and hardness of selected materials after heat treatment were also investigated. The pin on plate test was used in order to examine the tribological properties of the analyzed materials. Findings: On the basis of the results of the research, it was found that it is possible to obtain gradient materials by the powder metallurgy methods, in order to ensure the required properties and structure of the designed material. It was shown that the new sintered graded materials are characterized by a multiphase structure, consisting of ferrite, primary carbides of the high speed steel, of the MC and M6C type, and dependently of the reinforcement phase, of the tungsten carbide WC which are introduced into the material, in the powder form. It has been proved by the pin on plate test that the addition of the tungsten carbide to the high-speed steel significantly improved the tribological properties. Practical implications: Developed material is tested for turning tools. Originality/value: The material presented in this paper has layers consisting of the carbide-steel with growing hardness on one side, and on the other side the high-speed steel, characterized by a high ductility.

4

Wpływ temperatury spiekania na właściwości tworzyw z ZnO

Wiśniewski P.

Szkło i Ceramika

|

2009

|

R. 60, nr 4

17-21

PL

W artykule opisano podstawowe właściwości i zastosowanie tlenku cynku. W części doświadczalnej przedstawiono wyniki badań nad wpływem temperatury spiekania na właściwości kształtek z tlenku cynku otrzymanych metodą prasowania jednostronnego. Próbki spiekano w trzech temperaturach: 900, 1000 i 1100 stopni Celsjusza i porównano właściwości kształtek tj. gęstość, porowatość otwartą, nasiąkliwość wodną, skurczliwość i wytrzymałość mechaniczną na zginanie określoną metodą trójpunktową.

EN

The paper presents the fundamental properties and application of zinc oxide. In experimental part the results of influence the sintering temperature on parameters of ZnO-based materials obtained by die pressing. The samples were sintered at three temperatures 900, 1000,1100 degrees centigrade and compare parameters: density, open porosity, water absorption, shrinkage and three-point bending strength.

5

Structure and properties of the gradient tool materials based on a high-speed steel HS6-5-2 reinforced with WC or VC carbides

Dobrzański L. A., Kloc-Ptaszna A.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

Vol. 37, nr 2

213-237

EN

Purpose: This paper concerns manufacturing and researching a new group of the gradient tool materials, manufactured by a conventional powder metallurgy method, consisting in compacting a powder in a closed die and sintering it. Design/methodology/approach: The materials were obtained by mixing the powders of the HS6-5-2 high-speed steel, tungsten carbide (WC), and vanadium carbide (VC). The mixes were poured one by one into the die, yielding layers with the gradually changing volume ratio of carbides within the high-speed steel matrix. Structural research by using the scanning and transmission electron microscopes, x-ray microanalysis and density, hardness and porosity tests, were performed. Structure and hardness of selected materials after heat treatment were also investigated. Findings: On the basis of the results of the research, it was found that it was possible to obtain gradient materials by the powder metallurgy methods, in order to ensure the required properties and structure of the designed material. It was shown that the new sintered graded materials were characterized by a multiphase structure, consisting of ferrite, primary carbides of the high speed steel, of the MC and M6C type, and dependently of the reinforcement phase, of the tungsten carbide WC or the vanadium carbide VC, which were introduced into the material, in the form of powder. Additionally in the structure of the WC-reinforced materials the W2C phase occurs. The gradient tool materials reinforced with the WC carbide were characterized by a higher hardness, and a lower porosity in relation to the materials reinforced with the VC carbide. It was found that the desired structure and properties (density, porosity and hardness) had the material containing 25% of the WC carbide in the surface layer, after sintering at the temperature 1210oC, for 30 minutes. The heat treatment application causes a significant increase of the surface layer hardness of the material. The highest surface layer hardness, equal to 71.6 HRC, shows the material austenitized at the temperature 1120şC, hardened and tempered twice at the temperature 530oC. Practical implications Developed material is tested for turning tools. Originality/value: The material presented in this paper has layers consisting of the carbide-steel with growing hardness on one hand, and the high-speed steel, characterized by a high ductility on the other.

6

Structure and properties of gradient tool materials with the high-speed steel matrix

Dobrzański L. A., Kloc-Ptaszna A., Matula G., Torralba J. M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2007

|

Vol. 24, nr 2

47-50

EN

Purpose: This work concerns research on the structure and properties of gradient tool materials with the HS6-5-2 high-speed steel matrix reinforced by the tungsten carbide. Design/methodology/approach: The materials were fabricated using the conventional powder metallurgy method, consisting in compacting the powder in a closed die, and subsequent sintering. All the sintered test pieces were subjected to examination of density, porosity, and hardness; observations were also made using the scanning electron microscope (SEM), equipped with the back-scatter electrons detector (BSE) and the dispersive energy analyser (EDAX D4). Findings: The density of the compacted and sintered test pieces grows along with the sintering temperature increase. The porosity grows along with the WC content growth in the particular layers. It was observed that the sintering time has an effect on the porosity growth. The longer the sintering time is, the higher the porosity is. The HRA hardness of the compacted and sintered test pieces grows along with the sintering temperature increase. It was noted that application of a longer sintering time results in slight hardness lowering. Practical implications: Developed material is tested for turning tools. Originality/value: The material presented in this paper has layers consisting of the carbide-steel with growing hardness on one side, and on the other side the high-speed steel, characterized by a high ductility.

7

Structure of the gradient carbide steels of HS 6-5-2 high-speed steel matrix

Dobrzański L. A., Kloc-Ptaszna A., Matula G., Torralba J. M.

Archives of Materials Science and Engineering

|

2007

|

Vol. 28, nr 10

589-592

EN

Purpose: The goal of this work is to obtain gradient carbide steels based on a high-speed steel reinforced with tungsten carbide. Design/methodology/approach: The materials were fabricated using the conventional powder metallurgy method. The gradient carbide steels was fabricated by mixing high-speed steel with WC powders. The uniaxial pressing before sintering was used for manufacturing the materials, consisting in compacting the powder in a closed die, and subsequent sintering. The sintered test pieces observations were also made using the scanning electron microscope (SEM), equipped with the back-scatter electrons detector (BSE) and the dispersive energy analyser (EDAX D4). Findings: It was observed that the as-sintered properties of gradient carbide steels are strongly affected by the tungsten carbide content. Practical implications: Developed material is tested for cutting tools. Originality/value: The material presented in this paper has layers, at one side consisting of the high-speed steel, characterized by a high ductility and at the other side the carbide steel characterized by a higher hardness. A forming methods were developed for high-speed and WC powders, making it possible to obtain materials with seven layers in their structure.