Piotr Klimczyk - Academia.edu (original) (raw)

Papers by Piotr Klimczyk

The simulation was aimed to determine of the temperature distribution in the Bridgman-type toroid... more The simulation was aimed to determine of the temperature distribution in the Bridgman-type toroidal apparatus in the initial stage of the sintering process. Calculations were performed using finite element method (FEM). Geometric model which mapped graphite heating element, the sintered material and mineral-polymer gaskets, which fulfill the role of a pressure medium, as well as electrical and thermal insulator was used. Heating in the model is realized by the flow of electric current whose changes as a function of time, correspond to the actual values occurring during the sintering process using the high-pressure high temperature apparatus - HPHT (High Pressure High Temperature). Verification of the results was made on the basis comparison of the calculated values of voltage and current flow, and temperature to the values recorded in the control measurements. The resulting good agreement comparison values for the presented model allows for its further development of, considering th...

Mechanik, 2015

Przedstawiono główne założenia, pozwalające na modelowy opis zagadnień mechanicznych i cieplnych ... more Przedstawiono główne założenia, pozwalające na modelowy opis zagadnień mechanicznych i cieplnych występujących podczas spiekania z użyciem toroidalnych kowadeł Bridgmana. Na ich podstawie skonstruowano modele obliczeniowe, w których wykorzystano rzeczywistą geometrię kowadeł i wszystkich części składowych istotnych dla modelowanego procesu. Obliczenia wykonano metodą elementów skończonych, z zastosowaniem komercyjnego środowiska obliczeniowego ANSYS. Uzyskane wyniki porównano z wartościami zarejestrowanymi podczas pomiarów kontrolnych, co pozwoliło na potwierdzenie słuszności przedstawionych założeń w obszarze zjawisk cieplnych. SŁOWA KLUCZOWE: toroidalne kowadło Bridgmana, metoda elementów skończonych, spiekanie

Ceramics International, 2013

The influence of high speed centrifugal compaction process, the HCP method, on the properties of ... more The influence of high speed centrifugal compaction process, the HCP method, on the properties of green compacts and sintered samples of Al 2 O 3 and ZrO 2 micropowders was investigated. This method may reduce friction between particles and prevent bridging of particles during compaction. The properties of the sintered materials strongly depend on the conditions of the centrifugal process: i.e. duration, rotation speed, solid content and dispersive liquids. The centrifugal compaction process of powder forming often results in gradient phase composition. An algorithm describing sedimentation of a group of spherical particles of different sizes and of different materials was used. Calculations for Al 2 O 3 and ZrO 2 deposition for the real conditions of the high-speed centrifugal compaction process have been carried out using the Barnea-Mizrahi equation. Deposition was carried out using an ultra-centrifuge with rotational speeds of 10,000, 20,000 and 30,000 rpm for various pH of dispersive liquids. Pore size and pore size distribution of Al 2 O 3 and ZrO 2 green compacts were measured by the mercury porosimetry method. Densities, Young's moduli and Vickers hardness distribution of sintered compacts prepared in various conditions are reported.

International Journal of Refractory Metals and Hard Materials, 2014

ABSTRACT Three types of polycrystalline diamond composites (PCDs) were studied. The first materia... more ABSTRACT Three types of polycrystalline diamond composites (PCDs) were studied. The first material was sintered using the mixture containing 80 wt % diamond, 15 wt % of Ti-Si-C powder (mixture of 47.1 wt % Ti3SiC2 and TiSi2, TiC and SiC, from self-propagating high-temperature synthesis) and 5 wt % nanometric Ti(CN) powders. The second material was prepared using diamond powder and 10 wt% of titanium diboride. Materials were sintered using a Bridgman-type high-pressure apparatus at 8 GPa and at the temperature of 2000 °C. The third material was a commercial PCD containing 88 wt % of diamond, 10 wt% of Co and 2 wt% of WC. The coefficients of friction for diamond composites in a sliding contact with an Al2O3 ceramic ball were determined from room temperature up to 800 °C, in air. X-ray diffraction patterns of diamond composites after HP-HT sintering and wear tests, are presented. In the studies, due to using Raman spectroscopy the strong influence of the bonding phase on the oxidation of diamond composites was confirmed. The most thermally stable material is the diamond composite with TiB2. High temperature bonding phase for diamond composites guarantees higher hardness and low coefficient of friction at elevated temperatures.

Ceramics International, 2009

In this work, the fabrication of bulk TiC 0.7 /TiB 2 nanostructured composites through metastable... more In this work, the fabrication of bulk TiC 0.7 /TiB 2 nanostructured composites through metastable transformation processing is investigated by taking advantages of two non-conventional powder metallurgy methods. First, the highly metastable TiC 0.7 /TiB 2 agglomerated powders are synthesized by the so-called self-propagating high-temperature synthesis (SHS), followed by rapid quenching. Then, the spark plasma sintering (SPS) method is adopted to consolidate the SHSed powders.

Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009

Nanostructured free-standing materials with the near-eutectic composition ZrO2–60wt.% Al2O3were p... more Nanostructured free-standing materials with the near-eutectic composition ZrO2–60wt.% Al2O3were prepared by atmospheric plasma spraying (APS) of micron-scale powders plus subsequent quenching using liquid nitrogen-cooled substrates. The microstructure was characterized by X-ray diffraction (XRD), SEM, and TEM, and the influence of thermal treatment at 1400° C on the mechanical properties like bending strength, Young’s modulus, microhardness as well as the friction

Key Engineering Materials, 2015

In the presented work the effect of graphene platelets (GPLs) grade and mixture homogenization pa... more In the presented work the effect of graphene platelets (GPLs) grade and mixture homogenization parameters on the microstructure and selected properties of Si 3 N 4 -graphene composites have been investigated. Three different commercial grades of the multilayer graphene platelets were used as a filler for ceramic matrix. The mixtures of silicon nitride powder with 2wt% of GPLs were prepared using planetary mill at 200 -400 rpm for 1 -16 h. The water, acetone and isopropanol have been tested as a wetting medium. The composites were sintered using Spark Plasma Sintering -SPS at 1650 °C under 35 MPa of uniaxial pressure during the whole cycle. Microstructure, density, Young modulus, hardness and indentation fracture toughness of the sintered samples have been investigated. The microstructure homogeneity of the composites depends mainly on the milling duration. Milling process should last for about 4 -8 h at 200 rpm for optimum results. Mechanical properties of the composites are slightly varied depending on the mixture preparation parameters. The homogenization time has a little stronger influence on the Young's modulus and hardness in the case of composites containing larger graphene sheets, in connection with the fragmentation of its microstructure. The best properties have composites reinforced by the GPLs characterised both by the smallest thickness and lateral size of nanosheets.

Journal of Superhard Materials, 2015

ABSTRACT In these studies, one group of PCD materials has been prepared using diamond powder and ... more ABSTRACT In these studies, one group of PCD materials has been prepared using diamond powder and 10 wt % of TiB2 and the second batch of the PCD material has been prepared using a mixture of diamond powder with 5 wt % of TiB2 and 2 wt % of Co. The materials have been sintered using a Bridgman�type high�pressure apparatus at 8.0 ± 0.2 GPa and a temperature of 2000 ± 50 °C. Thermogravimetric (TG) measurements and Differential Thermal Analysis (DTA) have been carried out for diamond micropowders, TiB2 bonding phase, and sintered composites. The coefficients of friction for diamond composites in a sliding contact with an Al2O3 ceramic ball have been determined from the room temperature up to 800°C. Material phase compositions were analyzed for initial samples and after wear tests, at the temperature of 800°C. Raman spectra of diamond composites with borides bonding phases, observed for the first�order zone center modes of diamond and graphite during heating up to 800°C in air have been presented. Thermal properties have been compared with the commercial diamond–cobalt PCD. It has been found that diamond with TiB2 and Co is the most resistant to the hardness changes at elevated temperatures and this material maintains the high hardness value up to 800°C but it has a high coefficient of friction.

Journal of Alloys and Compounds, 2004

Theoretical and experimental studies of cubic BN mixed with Ti and TiN in the molar ratio 1:1 are... more Theoretical and experimental studies of cubic BN mixed with Ti and TiN in the molar ratio 1:1 are reported and compared with the properties of Ti and TiN films grown by the arc plasma deposition method on cBN substrate. Theoretical calculations show that Ti and TiN react with cubic BN forming new phases at 1000 and 1400°C. The cBN composites

Purpose: The paper analyzes the influence of the temperature and pressure on the properties and s... more Purpose: The paper analyzes the influence of the temperature and pressure on the properties and structure of the austenitic AISI 316L stainless steel reinforced with 1% vol.TiB2 ceramics.Design/methodology/approach: The sintered austenitic AISI 316L stainless steel reinforced with 1% vol.TiB2 were obtained using the high temperature-high pressure (HT-HP) method at pressure of 5.0 and 7.5 ± 0.2 GPa and temperatures 900°C, 1150°C and 1300°C. The duration of sintering was 60 seconds. Young’s modulus measurements were carried out using ultrasonic method. Mechanical properties were determined by Vickers hardness test. For microstructure observation scanning electron microscope JEOL JSM-6460LV was used.Findings: The decrease of the hardness of the sintered austenitic AISI 316L stainless steel with the increasing temperature of sintering was observed. However, the Young’s modulus increases with the growth of the temperature of sintering. The results showed that the hardness increased with ...

Purpose: The purpose of the presented work is to study the influence of different Si3N4 and SiC p... more Purpose: The purpose of the presented work is to study the influence of different Si3N4 and SiC powders on mechanical properties of Si3N4–SiC composites, to obtain a hard and tough engineering material, especially for cutting applications.Design/methodology/approach: Three kinds of Si3N4 – SiC composite, with initial powders of different grain size: micro-, submicro- and nano-structured, were sintered by the HPHT (High-Pressure High-Temperature) method. Several variants were made of each composite, with different Si3N4 to SiC phase volume ratios. The influence of grain size of the initial Si3N4 and SiC powders on mechanical properties of sintered materials was investigated. Density, Young’s modulus, hardness and fracture toughness of composites were measured. Microstructural (SEM) investigations were also conducted for selected samples.Findings: A strong influence of initial powder size on mechanical properties of Si3N4 – SiC composites can be observed. Sintered materials obtained f...

Physics, Chemistry and Application of Nanostructures - Reviews and Short Notes - Proceedings of the International Conference on Nanomeeting 2009, 2009

Physics, Chemistry and Applications of Nanostructures - Reviews and Short Notes - Proceedings of International Conference Nanomeeting – 2011, 2011

Journal of the European Ceramic Society, 2015

ABSTRACT The study concerns silicon nitride based composites with an up to 10 wt% graphene nonofl... more ABSTRACT The study concerns silicon nitride based composites with an up to 10 wt% graphene nonoflakes (GNP) addition. An XRD and Raman analysis of hot-pressed prepared composites were conducted. The microstructural SEM observations supported by element EDS analysis were also made. Elastic and mechanical properties (Knoop hardness, bending strength, fracture toughness) were measured. The manufactured sinters were put to friction coefficient and wear tests. Wear scars on discs after the abrasion tests were observed by optical and SEM microscopy. Performance examinations of hot-pressed cutting tools were performed.

Processing and Application of Ceramics, 2009

ABSTRACT The effects of compacting pressure, powder degassing and high pressure sintering tempera... more ABSTRACT The effects of compacting pressure, powder degassing and high pressure sintering temperature and time on the densification and properties of nanocrystalline titanium nitride have been investigated. For this reason, TiN powder with a mean particle size of 55 nm was pressed in the range of compacting pressure from 0.2 to 1.0 GPa and sintered under static pressure of 3.5 GPa in the temperature range of 900–1600°C for 45–120 s. Some of green bodies were degassed in vacuum before sintering. It was shown that samples compacted in the pressure range of 0.2–0.6 GPa have the highest density after the thermobaric treatment. The maximum density (about 97.3 %TD) was obtained with degassed samples. Microhardness and microstructure investigations have shown that recrystallization of the TiN nanopowder begins at the sintering temperatures of 1100–1200°C and sintering time less than one minute. The maximum microhardness obtained was 23.2±1.0 GPa and the maximum Young modulus was 370 GPa.

The simulation was aimed to determine of the temperature distribution in the Bridgman-type toroid... more The simulation was aimed to determine of the temperature distribution in the Bridgman-type toroidal apparatus in the initial stage of the sintering process. Calculations were performed using finite element method (FEM). Geometric model which mapped graphite heating element, the sintered material and mineral-polymer gaskets, which fulfill the role of a pressure medium, as well as electrical and thermal insulator was used. Heating in the model is realized by the flow of electric current whose changes as a function of time, correspond to the actual values occurring during the sintering process using the high-pressure high temperature apparatus - HPHT (High Pressure High Temperature). Verification of the results was made on the basis comparison of the calculated values of voltage and current flow, and temperature to the values recorded in the control measurements. The resulting good agreement comparison values for the presented model allows for its further development of, considering th...

Mechanik, 2015

Przedstawiono główne założenia, pozwalające na modelowy opis zagadnień mechanicznych i cieplnych ... more Przedstawiono główne założenia, pozwalające na modelowy opis zagadnień mechanicznych i cieplnych występujących podczas spiekania z użyciem toroidalnych kowadeł Bridgmana. Na ich podstawie skonstruowano modele obliczeniowe, w których wykorzystano rzeczywistą geometrię kowadeł i wszystkich części składowych istotnych dla modelowanego procesu. Obliczenia wykonano metodą elementów skończonych, z zastosowaniem komercyjnego środowiska obliczeniowego ANSYS. Uzyskane wyniki porównano z wartościami zarejestrowanymi podczas pomiarów kontrolnych, co pozwoliło na potwierdzenie słuszności przedstawionych założeń w obszarze zjawisk cieplnych. SŁOWA KLUCZOWE: toroidalne kowadło Bridgmana, metoda elementów skończonych, spiekanie

Ceramics International, 2013

The influence of high speed centrifugal compaction process, the HCP method, on the properties of ... more The influence of high speed centrifugal compaction process, the HCP method, on the properties of green compacts and sintered samples of Al 2 O 3 and ZrO 2 micropowders was investigated. This method may reduce friction between particles and prevent bridging of particles during compaction. The properties of the sintered materials strongly depend on the conditions of the centrifugal process: i.e. duration, rotation speed, solid content and dispersive liquids. The centrifugal compaction process of powder forming often results in gradient phase composition. An algorithm describing sedimentation of a group of spherical particles of different sizes and of different materials was used. Calculations for Al 2 O 3 and ZrO 2 deposition for the real conditions of the high-speed centrifugal compaction process have been carried out using the Barnea-Mizrahi equation. Deposition was carried out using an ultra-centrifuge with rotational speeds of 10,000, 20,000 and 30,000 rpm for various pH of dispersive liquids. Pore size and pore size distribution of Al 2 O 3 and ZrO 2 green compacts were measured by the mercury porosimetry method. Densities, Young's moduli and Vickers hardness distribution of sintered compacts prepared in various conditions are reported.

International Journal of Refractory Metals and Hard Materials, 2014

ABSTRACT Three types of polycrystalline diamond composites (PCDs) were studied. The first materia... more ABSTRACT Three types of polycrystalline diamond composites (PCDs) were studied. The first material was sintered using the mixture containing 80 wt % diamond, 15 wt % of Ti-Si-C powder (mixture of 47.1 wt % Ti3SiC2 and TiSi2, TiC and SiC, from self-propagating high-temperature synthesis) and 5 wt % nanometric Ti(CN) powders. The second material was prepared using diamond powder and 10 wt% of titanium diboride. Materials were sintered using a Bridgman-type high-pressure apparatus at 8 GPa and at the temperature of 2000 °C. The third material was a commercial PCD containing 88 wt % of diamond, 10 wt% of Co and 2 wt% of WC. The coefficients of friction for diamond composites in a sliding contact with an Al2O3 ceramic ball were determined from room temperature up to 800 °C, in air. X-ray diffraction patterns of diamond composites after HP-HT sintering and wear tests, are presented. In the studies, due to using Raman spectroscopy the strong influence of the bonding phase on the oxidation of diamond composites was confirmed. The most thermally stable material is the diamond composite with TiB2. High temperature bonding phase for diamond composites guarantees higher hardness and low coefficient of friction at elevated temperatures.

Ceramics International, 2009

In this work, the fabrication of bulk TiC 0.7 /TiB 2 nanostructured composites through metastable... more In this work, the fabrication of bulk TiC 0.7 /TiB 2 nanostructured composites through metastable transformation processing is investigated by taking advantages of two non-conventional powder metallurgy methods. First, the highly metastable TiC 0.7 /TiB 2 agglomerated powders are synthesized by the so-called self-propagating high-temperature synthesis (SHS), followed by rapid quenching. Then, the spark plasma sintering (SPS) method is adopted to consolidate the SHSed powders.

Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009

Nanostructured free-standing materials with the near-eutectic composition ZrO2–60wt.% Al2O3were p... more Nanostructured free-standing materials with the near-eutectic composition ZrO2–60wt.% Al2O3were prepared by atmospheric plasma spraying (APS) of micron-scale powders plus subsequent quenching using liquid nitrogen-cooled substrates. The microstructure was characterized by X-ray diffraction (XRD), SEM, and TEM, and the influence of thermal treatment at 1400° C on the mechanical properties like bending strength, Young’s modulus, microhardness as well as the friction

Key Engineering Materials, 2015

In the presented work the effect of graphene platelets (GPLs) grade and mixture homogenization pa... more In the presented work the effect of graphene platelets (GPLs) grade and mixture homogenization parameters on the microstructure and selected properties of Si 3 N 4 -graphene composites have been investigated. Three different commercial grades of the multilayer graphene platelets were used as a filler for ceramic matrix. The mixtures of silicon nitride powder with 2wt% of GPLs were prepared using planetary mill at 200 -400 rpm for 1 -16 h. The water, acetone and isopropanol have been tested as a wetting medium. The composites were sintered using Spark Plasma Sintering -SPS at 1650 °C under 35 MPa of uniaxial pressure during the whole cycle. Microstructure, density, Young modulus, hardness and indentation fracture toughness of the sintered samples have been investigated. The microstructure homogeneity of the composites depends mainly on the milling duration. Milling process should last for about 4 -8 h at 200 rpm for optimum results. Mechanical properties of the composites are slightly varied depending on the mixture preparation parameters. The homogenization time has a little stronger influence on the Young's modulus and hardness in the case of composites containing larger graphene sheets, in connection with the fragmentation of its microstructure. The best properties have composites reinforced by the GPLs characterised both by the smallest thickness and lateral size of nanosheets.

Journal of Superhard Materials, 2015

ABSTRACT In these studies, one group of PCD materials has been prepared using diamond powder and ... more ABSTRACT In these studies, one group of PCD materials has been prepared using diamond powder and 10 wt % of TiB2 and the second batch of the PCD material has been prepared using a mixture of diamond powder with 5 wt % of TiB2 and 2 wt % of Co. The materials have been sintered using a Bridgman�type high�pressure apparatus at 8.0 ± 0.2 GPa and a temperature of 2000 ± 50 °C. Thermogravimetric (TG) measurements and Differential Thermal Analysis (DTA) have been carried out for diamond micropowders, TiB2 bonding phase, and sintered composites. The coefficients of friction for diamond composites in a sliding contact with an Al2O3 ceramic ball have been determined from the room temperature up to 800°C. Material phase compositions were analyzed for initial samples and after wear tests, at the temperature of 800°C. Raman spectra of diamond composites with borides bonding phases, observed for the first�order zone center modes of diamond and graphite during heating up to 800°C in air have been presented. Thermal properties have been compared with the commercial diamond–cobalt PCD. It has been found that diamond with TiB2 and Co is the most resistant to the hardness changes at elevated temperatures and this material maintains the high hardness value up to 800°C but it has a high coefficient of friction.

Journal of Alloys and Compounds, 2004

Theoretical and experimental studies of cubic BN mixed with Ti and TiN in the molar ratio 1:1 are... more Theoretical and experimental studies of cubic BN mixed with Ti and TiN in the molar ratio 1:1 are reported and compared with the properties of Ti and TiN films grown by the arc plasma deposition method on cBN substrate. Theoretical calculations show that Ti and TiN react with cubic BN forming new phases at 1000 and 1400°C. The cBN composites

Purpose: The paper analyzes the influence of the temperature and pressure on the properties and s... more Purpose: The paper analyzes the influence of the temperature and pressure on the properties and structure of the austenitic AISI 316L stainless steel reinforced with 1% vol.TiB2 ceramics.Design/methodology/approach: The sintered austenitic AISI 316L stainless steel reinforced with 1% vol.TiB2 were obtained using the high temperature-high pressure (HT-HP) method at pressure of 5.0 and 7.5 ± 0.2 GPa and temperatures 900°C, 1150°C and 1300°C. The duration of sintering was 60 seconds. Young’s modulus measurements were carried out using ultrasonic method. Mechanical properties were determined by Vickers hardness test. For microstructure observation scanning electron microscope JEOL JSM-6460LV was used.Findings: The decrease of the hardness of the sintered austenitic AISI 316L stainless steel with the increasing temperature of sintering was observed. However, the Young’s modulus increases with the growth of the temperature of sintering. The results showed that the hardness increased with ...

Purpose: The purpose of the presented work is to study the influence of different Si3N4 and SiC p... more Purpose: The purpose of the presented work is to study the influence of different Si3N4 and SiC powders on mechanical properties of Si3N4–SiC composites, to obtain a hard and tough engineering material, especially for cutting applications.Design/methodology/approach: Three kinds of Si3N4 – SiC composite, with initial powders of different grain size: micro-, submicro- and nano-structured, were sintered by the HPHT (High-Pressure High-Temperature) method. Several variants were made of each composite, with different Si3N4 to SiC phase volume ratios. The influence of grain size of the initial Si3N4 and SiC powders on mechanical properties of sintered materials was investigated. Density, Young’s modulus, hardness and fracture toughness of composites were measured. Microstructural (SEM) investigations were also conducted for selected samples.Findings: A strong influence of initial powder size on mechanical properties of Si3N4 – SiC composites can be observed. Sintered materials obtained f...

Physics, Chemistry and Application of Nanostructures - Reviews and Short Notes - Proceedings of the International Conference on Nanomeeting 2009, 2009

Physics, Chemistry and Applications of Nanostructures - Reviews and Short Notes - Proceedings of International Conference Nanomeeting – 2011, 2011

Journal of the European Ceramic Society, 2015

ABSTRACT The study concerns silicon nitride based composites with an up to 10 wt% graphene nonofl... more ABSTRACT The study concerns silicon nitride based composites with an up to 10 wt% graphene nonoflakes (GNP) addition. An XRD and Raman analysis of hot-pressed prepared composites were conducted. The microstructural SEM observations supported by element EDS analysis were also made. Elastic and mechanical properties (Knoop hardness, bending strength, fracture toughness) were measured. The manufactured sinters were put to friction coefficient and wear tests. Wear scars on discs after the abrasion tests were observed by optical and SEM microscopy. Performance examinations of hot-pressed cutting tools were performed.

Processing and Application of Ceramics, 2009

ABSTRACT The effects of compacting pressure, powder degassing and high pressure sintering tempera... more ABSTRACT The effects of compacting pressure, powder degassing and high pressure sintering temperature and time on the densification and properties of nanocrystalline titanium nitride have been investigated. For this reason, TiN powder with a mean particle size of 55 nm was pressed in the range of compacting pressure from 0.2 to 1.0 GPa and sintered under static pressure of 3.5 GPa in the temperature range of 900–1600°C for 45–120 s. Some of green bodies were degassed in vacuum before sintering. It was shown that samples compacted in the pressure range of 0.2–0.6 GPa have the highest density after the thermobaric treatment. The maximum density (about 97.3 %TD) was obtained with degassed samples. Microhardness and microstructure investigations have shown that recrystallization of the TiN nanopowder begins at the sintering temperatures of 1100–1200°C and sintering time less than one minute. The maximum microhardness obtained was 23.2±1.0 GPa and the maximum Young modulus was 370 GPa.