Pulse Plasma Sintering of Nano-Crystalline Cu Powder

2006 ◽  
Vol 114 ◽  
pp. 239-244 ◽  
Author(s):  
Andrzej Michalski ◽  
Marcin Rosiński ◽  
D. Siemiaszko ◽  
Jakub Jaroszewicz ◽  
Krzysztof Jan Kurzydlowski

Nanocrystalline copper powders, produced by the reduction of the CuO with hydrogen, were consolidated using the pulse plasma sintering (PPS) method. The sintering process was carried out at temperatures between 500 and 900 oC under a load of 60 MPa for 5 min. The average crystallite size of the sintered component obtained at 500 oC was about 80nm and at 900 oC 1880 nm. The components produced at 500 oC had a relative density of 90 %, and those sintered at 900 oC 92 %; their hardness was 215 and 140 HV0.1, respectively.

2006 ◽  
Vol 114 ◽  
pp. 227-232 ◽  
Author(s):  
Andrzej Michalski ◽  
Jakub Jaroszewicz ◽  
Marcin Rosiński ◽  
D. Siemiaszko ◽  
Krzysztof Jan Kurzydlowski

The paper presents the results of examination of the structure and properties of nanocrystalline Cu-Al2O3 composites with the two different Al2O3 contents: 10 and 20 vol.%. The composites were produced using a mixture of copper and Al2O3 powders with an average crystallite size of about 60nm for Cu and about 40nm for Al2O3. The powders were consolidated by pulse plasma sintering (PPS) for 5 minutes at a temperature of 650oC under a load of 60 MPa. Irrespective of the volumetric content of Al2O3, the relative density of the composites was about 92%, and the average Cu crystallite size was about 80nm. The hardness of the composites varied with the volumetric content of Al2O3, and was equal to 270 HV0.1 for 20 and to 240 HV0.1 for 10% of Al2O3. The Cu-20%Al2O3 composite had a resistivity of 0.386 while that with 10% of Al2O3 was 0.149 56m.


2006 ◽  
Vol 114 ◽  
pp. 245-250
Author(s):  
Andrzej Michalski ◽  
D. Siemiaszko ◽  
Jakub Jaroszewicz ◽  
Marcin Rosiński ◽  
M. Psoda

Nanocrystalline WC-12wt.%Co was consolidated by Pulse Plasma Sintering (PPS) at various temperatures between 900 and 1200oC for 6 minutes under a pressure of 60MPa. Cemented carbides sintered at 1100oC have a relative density of 99%, a hardness of 2248HV30, the fracture toughness, KIC=12.5 MPa*m1/2, and have a structure containing 50nm WC crystallites. Increasing the sintering temperature to 1200oC causes an increase in the size of the WC crystallite size to about 110 nm, reduces the hardness to 2198HV30, and decreases the KIC to 9.7 MPa*m1/2.


2011 ◽  
Vol 484 ◽  
pp. 130-134 ◽  
Author(s):  
Marcin Rosiński ◽  
Andrzej Michalski ◽  
Magdalena Płocińska ◽  
Jerzy Szawłowski

Tungsten carbide (WC) and WCCo powders added with 30 vol.% cubic boron nitride (cBN) and 5 and 12 wt% of Ti were sintered by the pulse plasma sintering (PPS) technique. The sintering process was conducted under a load of 75 MPa at a pressure of 5.10- 5 mbar and a temperature of 1100-1500°C for 5min. The phase composition, density, hardness and microstructure of the sintered material thus obtained were examined. In the cBN-WCTi5wt% composite with an addition of 6wt% Co, the cBN particles are well bound with the matrix. The transcrystalline fractures of the cBN particles also indicate that the binding forces between these particles and the WCCoTi matrix exceed the matrix cohesion. The interfaces between the cBN grains and the surrounding matrix are almost straight lines, and no reactions between the cBN grains and the matrix were revealed in SEM observations.


Author(s):  
A. Michalski ◽  
M. Rosiński ◽  
D. Siemiaszko ◽  
Jakub Jaroszewicz ◽  
Krzysztof J. Kurzydłowski

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3398
Author(s):  
Katarzyna Konopka ◽  
Marek Krasnowski ◽  
Justyna Zygmuntowicz ◽  
Konrad Cymerman ◽  
Marcin Wachowski ◽  
...  

The paper describes an investigation of Al2O3 samples and NiAl–Al2O3 composites consolidated by pulse plasma sintering (PPS). In the experiment, several methods were used to determine the properties and microstructure of the raw Al2O3 powder, NiAl–Al2O3 powder after mechanical alloying, and samples obtained via the PPS. The microstructural investigation of the alumina and composite properties involves scanning electron microscopy (SEM) analysis and X-ray diffraction (XRD). The relative densities were investigated with helium pycnometer and Archimedes method measurements. Microhardness analysis with fracture toughness (KIC) measures was applied to estimate the mechanical properties of the investigated materials. Using the PPS technique allows the production of bulk Al2O3 samples and intermetallic ceramic composites from the NiAl–Al2O3 system. To produce by PPS method the NiAl–Al2O3 bulk materials initially, the composite powder NiAl–Al2O3 was obtained by mechanical alloying. As initial powders, Ni, Al, and Al2O3 were used. After the PPS process, the final composite materials consist of two phases: Al2O3 located within the NiAl matrix. The intermetallic ceramic composites have relative densities: for composites with 10 wt.% Al2O3 97.9% and samples containing 20 wt.% Al2O3 close to 100%. The hardness of both composites is equal to 5.8 GPa. Moreover, after PPS consolidation, NiAl–Al2O3 composites were characterized by high plasticity. The presented results are promising for the subsequent study of consolidation composite NiAl–Al2O3 powder with various initial contributions of ceramics (Al2O3) and a mixture of intermetallic–ceramic composite powders with the addition of ceramics to fabricate composites with complex microstructures and properties. In composites with complex microstructures that belong to the new class of composites, in particular, the synergistic effect of various mechanisms of improving the fracture toughness will be operated.


2007 ◽  
Vol 82 (15-24) ◽  
pp. 2621-2626 ◽  
Author(s):  
M. Rosinski ◽  
E. Fortuna ◽  
A. Michalski ◽  
Z. Pakiela ◽  
K.J. Kurzydlowski

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