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Wyświetlanie 1-8 z 8
Tytuł:
Boride Layer Growth Kinetics of AISI H13 Steel Borided with Nano-Sized Powders
Autorzy:
Karakaş, M. S.
Günen, A.
Kanca, E.
Yilmaz, E.
Powiązania:
https://bibliotekanauki.pl/articles/351842.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
boriding
growth kinetics
activation energy
Opis:
Growth kinetics of boride layers in AISI H13 steel was investigated using the pack boriding method at temperatures of 1073, 1173 and 1273 K (800°C, 900°C and 1000°C) for periods of 2, 4 and 6 h with nano-sized boron (NB) and micron-sized Ekabor II powders as boriding agents. The total thickness of the boride layer (including both FeB and Fe2B) after boriding at 1273 K (1000°C) for 6 h was 103.8 μm and 96.5 μm for the NB and Ekabor II specimens, respectively. X-ray diffraction analysis of the boride layers on the surfaces borided with NB and Ekabor II revealed the presence of FeB and Fe2B phases with sawtooth morphology. The FeB/Fe2B volume ratio was higher in the specimens borided with NB. The thickness of the boride layer (FeB + Fe2B) increased with the increasing boriding temperature and time. The FeB layer in the NB specimen displayed a (002) preferred orientation.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 1; 159-165
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diffusion Kinetics of Binary Ti-Ni Shape Memory Alloys
Autorzy:
Ucar, N.
Dogan, S.
Ozdemir, A.
Karakas, S.
Calik, A.
Powiązania:
https://bibliotekanauki.pl/articles/1031122.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
boriding
shape memory alloys
microhardness
boride layer
diffusion
Opis:
In this work, the boriding of binary Ti-Ni shape memory alloys was carried out in a solid medium at 1173 and 1273 K for 2, 4, and 8 h using the powder pack method with Ekabor-Ni powders. The boride layer was characterized by optical microscopy and scanning electron microscopy. The obtained results show that boride layer thickness increases with the increasing boriding temperature and time. Depending on temperature and boride layer thickness, the diffusion process is thermally activated, with the mean value of the activation energy being close to 67 kJ/mol.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 524-526
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Erosive Wear Resistance of Boronized Ash-Blowing Nozzles
Autorzy:
Calik, A.
Ozbakir, O.
Karakas, S.
Ucar, N.
Powiązania:
https://bibliotekanauki.pl/articles/1030338.pdf
Data publikacji:
2017-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
boriding
wear resistance
boride layer
hardness
Opis:
In this study, pack boronizing was applied to ash-blowing nozzles manufactured from AISI 1040 steels using Ekabor II powders as the boronizing source at a temperature of 1273 K for a duration of 8 h. Erosive wear tests of boride ash-blowing nozzles were carried out in ash delivery line of thermal reactor under actual working conditions. It was observed that erosive wear resistance of borided ash-blowing nozzles were increased 3 times as a result of the boronizing process. The improved wear resistance of the borided samples can be explained by increased surface hardness and higher work hardening.
Źródło:
Acta Physica Polonica A; 2017, 131, 2; 252-254
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Different Phosphorus Precursors on Biomimetic Hydroxyapatite Powder Properties
Autorzy:
Karakaş, A.
Hazar Yoruç, A.
Gökçe, H.
Karabulut, A.
Ceylan Erdoğan, D.
Powiązania:
https://bibliotekanauki.pl/articles/1399963.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.J-
Opis:
Hydroxyapatite is the main component of natural hard tissues, such as teeth and bone. It has been studied extensively as a candidate biomaterial for its use in prosthetic applications. Hydroxyapatite was formulated as $Ca_{10}(PO_4)_6(OH)_2$ and it has a high stability under physiological conditions. Also hydroxyapatite can be synthesized using different calcium and phosphorus precursors. In this study, biomimetic hydroxyapatite powder has been synthesized simulating physiological conditions. Synthetic body fluids which have the same composition as human blood plasma instead of pure water were used as precipitation media to obtain biological conditions. Recent research involved the effect of different Ca-precursors however aim of this study is to determine the effect of phosphorus resources. In this study, the synthesis of hydroxyapatite powder is carried out by using biomimetic method in synthetic body fluids. Calcium acetate $[Ca(CH_3COO)_2, CA]$ and diammonium hydrogen phosphate $[(NH_4)_2HPO_4, DAHP]$, ammonium dihydrogen phosphate $[NH_4H_2PO_4, ADHP]$, dipotassium hydrogen phosphate $[K_2HPO_4, DPHP]$ and orthophosphoric acid $[H_3PO_4, OPA]$ were used as Ca- and P-precursors. Chemical structures of synthesized powders have been examined by Fourier transform infrared and X-ray diffraction. Results showed that synthesized powders have a pure hydroxyapatite structure. However, ADHP precursors have an unfavorable effect on sintered hydroxyapatite powders. Using ADHP phase transition was caused in pure hydroxyapatite structure and apatite and whitlockite were observed as secondary phases. Their particle size, surface area determination and morphological structures have been characterized by Zeta-Sizer, biomimetic hydroxyapatite the Brunauer-Emmett-Teller analysis and scanning electron microscopy images, respectively. As a result different starting materials have affected the structure, particle size and morphological properties of biomimetic hydroxyapatite.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 418-420
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Precipitation Method on Properties of Hydroxyapatite Powders
Autorzy:
Hazar Yoruç, A.
Karakaş, A.
Ayas, E.
Koyun, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399899.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.J-
Opis:
The aim of this study was the compare the properties of hydroxyapatite as a function of two different methods (chemical and biomimetic precipitation). Powder products were called as chemical hydroxyapatite for chemical method and biomimetic hydroxyapatite for biomimetic method. Precipitated powders with both methods were characterized by Fourier transform infrared, X-ray diffraction, X-ray fluorescence and measurements of hardness and density. Chemical analysis results showed that dried-biomimetic hydroxyapatite sample consists of hydroxyapatite $[Ca_{10}PO_4)_6(OH)_2]$ as main phase and beta-tricalcium phosphate (β-TCP) as secondary phase and dried-chemical hydroxyapatite sample also includes pure hydroxyapatite phase. Chemical hydroxyapatite and biomimetic hydroxyapatite powders were sintered using by spark plasma sintering method. Vickers hardness values of sintered disk samples were measured. Furthermore chemical structure of the final products was analyzed. Also density values of chemical hydroxyapatite and biomimetic hydroxyapatite disks were measured. Finally it is concluded that different precipitation methods affect hydroxyapatite properties and this can be an advantage for biomedical applications.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 371-373
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Properties of Hydroxyapatite Powders Synthesized by Chemical and Biomimetic Techniques
Autorzy:
Hazar Yoruç, A.
Karakaş, A.
Koyun, A.
Yildiz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1491408.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.J-
Opis:
Hydroxyapatite $[HA; Ca_{10}(PO_4)_6(OH)_2]$ which composes inorganic phase of bones and teeth is one of the biomedical materials for artificial bone, reconstruction of broken or disordered bones, coating of metallic biomedical materials and dental surgery with its great biocompatibility. In this study, HA powders were synthesized from aqueous suspensions containing $H_3PO_4$ and $Ca(OH)_2$ with 1.67 Ca/P ratios (chemical HA, CHA) and second process is carried out in simulated body fluids consisting of $(NH_4)_2HPO_4$ and $Ca(NO_3)_2 \cdot 4H_2O$ as biomimetic hydroxyapatite (BHA). Moreover, properties of bovine HA (BoHA) and commercial HA (CoHA) were compared with properties of synthesized HA powders. Chemical structures of synthesized powders have been examined by the Fourier transform infrared technique and X-ray diffraction. The results showed that BHA powders have a pure HA content and no secondary phase, CHA also has monetite phase as secondary phase with HA in its structure. Particle size analysis was carried out with laser particle sizer and zeta-sizer, surface area of powders has been analyzed by the Brunauer-Emmett-Teller technique. Powder morphology is determined using scanning electron microscopy. As a result two different synthesis methods affected properties of HA powders.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 233-235
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Different Calcium Precursors on Biomimetic Hydroxyapatite Powder Properties
Autorzy:
Karakaş, A.
Hazar Yoruç, A.
Ceylan Erdoğan, D.
Doğan, M.
Powiązania:
https://bibliotekanauki.pl/articles/1491413.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.J-
Opis:
Hydroxyapatite is the main component of human hard tissues such as bones and teeth. Because it has a great biocompatibility with human organism, it is used as biomaterial with the purpose of form and repair hard tissues. Hydroxyapatite is formulated as $Ca_{10}(PO_4)_6(OH)_2$ and shows high stability under physiological conditions. In this study, biomimetic hydroxyapatite powder has been synthesized using by synthetic body fluids which has the same composition as human blood plasma. Moreover, the effect of different precursors on properties of synthesized powders has been investigated. For that purpose calcium nitrate tetrahydrate $[Ca(NO_3)_2 ·4H_2O]$, calcium chloride $[CaCl_2]$, calcium hydroxide $[Ca(OH)_2]$ and diammonium hydrogen phosphate $[(NH_4)_2HPO_4]$ were used as precursors. Mainly literature focused on the synthesis of hydroxyapatite powders was carried out using chemical method. However, in this study, the synthesis of hydroxyapatite powder is carried out using biomimetic method. Chemical structures of synthesized powders have been investigated by the Fourier transform infrared and X-ray diffraction methods. Results showed that synthesized powders have a pure hydroxyapatite structure. Surface area of the synthesized powders was measured by the Brunauer-Emmett-Teller method. Morphological structures have been characterized by using scanning electron microscopy. Furthermore, particle size of powders was calculated using the Brunauer-Emmett-Teller method. It was clearly seen that morphological properties of biomimetic hydroxyapatite have affected the use of different calcium precursors.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 236-239
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Hardness and Wear Behaviour οf Boronized and Carburized AISI 8620 Steels
Autorzy:
Calik, A.
Duzgun, A.
Ekinci, A.
Karakas, S.
Ucar, N.
Powiązania:
https://bibliotekanauki.pl/articles/1585043.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.-x
62.20.M-
62.20.Qp
68.35.Fx
Opis:
In this study, the hardness and wear behaviour of carburized and boronized AISI 8620 steels have been studied. The boronizing treatment increased the hardness of AISI 8620 steels from 395 $HV_{0.1}$ to a maximal 1610 $HV_{0.1}$ compared to the carburized steels and also significantly improved its wear behaviour. From obtained results, it can be concluded that boronizing is very effective surface hardening method for improving the wear properties of AISI 8620 steels.
Źródło:
Acta Physica Polonica A; 2009, 116, 6; 1029-1032
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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