Temat: niobium - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Hydrogen effect on the electronic and structural properties of Nb-Fe alloys
Autorzy:: Brzeska-Michalak, B.
Ostrasz, A.
Tematy:: Mössbauer spectroscopy of 57Fe
iron-niobium alloys
niobium hydrides; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/148793.pdf Link otwiera się w nowym oknie
Opis:: The influence of hydrogen on the electronic and structural properties of Nb1-yFey alloys has been studied with 57Fe Mössbauer spectroscopy and X-ray diffraction. No ability of hydrogen to creation of the ferromagnetic properties has been observed in this system. The results clearly indicate the ß-NbH0.85÷0.77 hydride formation in place of ?-Nb phase. The quadrupole splitting and the isomer shift of the ß-NbHx subspectrum have been considered in terms of interaction between the interstitials and the Mössbauer atoms within the hydride phase.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: The Effects of Niobium on the Bioactivity of Ni-Ti-Al-Nb Shape Memory Alloys
Autorzy:: Teixeira, Ricardo Luiz Perez
de Lacerda, José Carlos
Conceição, Isabella Carolina
da Silva, Sidney Nicodemos
Siqueira, Guilherme O.
Moura, Francisco
Tematy:: nitinol
niobium
aluminum
bioactivity
cytotoxicity; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2049692.pdf Link otwiera się w nowym oknie
Opis:: This work aims to analyze the effects of niobium on the bioactivity of a titanium, nickel, aluminum, and niobium alloy obtained by the Plasma Skull Push Pull process (PSPP). Titanium alloys, such as NiTinol (NiTi), are metallic biomaterials that have wide application in health and surgical prostheses. In this work the microstructural and bioactivity characteristics of the alloys are evaluated. The addition of aluminum improves alloy ductility and reduces its cost. The addition of niobium favors the hydroxyapatite nucleation. Therefore, the addition of the combination of the two elements contributes to lower cost and better alloy bioactivity.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Recovery of Niobium Pentaoxide and Ammonium Sulfate from Titanium-Magnesium Production Waste
Autorzy:: Ultarakova, Almagul
Lokhova, Nina
Karshyga, Zaure
Toishybek, Azamat
Yessengaziyev, Azamat
Kassymzhanov, Kaisar
Mukangaliyeva, Arailym
Tematy:: titanium residue
sludge
leaching
niobium chloride
niobium pentaoxide
purification
dust chamber
sublimation
desorption
ammonium sulfate; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/59113535.pdf Link otwiera się w nowym oknie
Opis:: This study was aimed to investigate the development of a technology for the extraction of niobium pentaoxide and ammonium sulfate from titanium-magnesium production waste, specifically, the sublimates of dust chamber into concentrate in the form of niobium pentoxide. Optimal conditions for washing the niobium hydroxide precipitate by repulpation with hot (60–70°C) distilled water, drying at 200°C for 6 hours were determined. The influence of temperature and duration of the process was studied. Optimal conditions for the dynamic desorption of niobium from saturated ionite (Purolite A100) was determined. The results further indicated that the optimum quantity of the solution of desorption with sulfuric acid was equal to 5.5% and ammonium oxalate was equal to 4%, while temperature and the flow rate of the desorbing solution was 22–27°C and 6 rpm, respectively. The study of the precipitation of niobium from sulfuric acid desorbates showed that the interaction of niobium ions with ammonia takes place at a low rate. The degree of precipitation of niobium hydroxide equal to 99.6% was achieved in 7 hours of agitation of the suspension at a temperature of 22–25°C.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: High Versatility of Niobium Alloyed AHSS
Autorzy:: Kučerová, L.
Opatová, K.
Káňa, J.
Jirková, H.
Tematy:: TRIP steel
niobium
heat treatment
thermomechanical treatment; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/958202.pdf Link otwiera się w nowym oknie
Opis:: The effect of processing parameters on the final microstructure and properties of advanced high strength CMnSiNb steel was investigated. Several processing strategies with various numbers of deformation steps and various cooling schedules were carried out, namely heat treatment without deformation, conventional quenching and TRIP steel processing with bainitic hold or continuous cooling. Obtained multiphase microstructures consisted of the mixture of ferrite, bainite, retained austenite and M-A constituent. They possessed ultimate tensile strength in the range of 780-970 MPa with high ductility A_{5 mm} above 30%. Volume fraction of retained austenite was for all the samples around 13%. The only exception was reference quenched sample with the highest strength 1186 MPa, lowest ductility A_{5 mm} = 20% and only 4% of retained austenite.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Preconcentration of a low-grade betafite ore by dense medium cyclone
Autorzy:: Lv, Zihu
Wei, Min
Zhao, Dengkui
Wu, Dongyin
Liu, Changmiao
Cheng, Hongwei
Tematy:: preconcentration
betafite
dense medium cyclone
uranium
niobium; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/2146943.pdf Link otwiera się w nowym oknie
Opis:: In order to find an economical and feasible short process for betafite preconcentrating and to provide a reference for the development of similar low-grade uranium deposits, preconcentration of the betafite ore was investigated based on mineralogical characterization study, float-sink tests, and dense medium cyclone (DMC) separation experiments. The float-sink test results revealed that the gravity separation of the betafite ore was feasible, and the expected particle size range was chosen to be 3~0.3 mm. The effect of important parameters of the DMC experiment such as particle size, grade of the feed, separation density, and inlet pressure on the separation performance of betafite ore was studied. Under the optimal experimental conditions, the expanded experiments were performed and the heavy minerals contained 4557 ppm U and 5200 ppm Nb2O5 with a recovery of 88.86% and 79.73%, respectively, were obtained. Besides, the enrichment ratio (E) values of U and Nb2O5 were 14.24 and 12.78 severally, and the tailings discarding ratio (R) value was 93.76%. The results demonstrate that the preconcentration of low-grade betafite by DMC can remove a large number of tailings and obtain a high-grade uranium concentrate.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Effects of Adding Niobium and Vanadium to Fe-Based Oxide Dispersion Strengthened Alloy
Autorzy:: Park, Chun Woong
Choi, Won June
Byun, Jong Min
Kim, Young Do
Tematy:: Fe-based ODS
vanadium
niobium
superalloy
hardness; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/353024.pdf Link otwiera się w nowym oknie
Opis:: In this study, the effects of adding niobium and vanadium to Fe-based oxide dispersion strengthened alloys are confirmed. The composition of alloys are Fe-20Cr-1Al-0.5Ti-0.5Y₂ O₃ and Fe-20Cr-1Al-0.5Ti-0.3V-0.2Nb-0.5Y₂ O₃. The alloy powders are manufactured by using a planetary mill, and these powders are molded by using a magnetic pulsed compaction. Thereafter, the powders are sintered in a tube furnace to obtain sintered specimens. The added elements exist in the form of a solid solution in the Fe matrix and suppress the grain growth. These results are confirmed via X-ray diffraction and scanning electron microscopy analyses of the phase and microstructure of alloys. In addition, it was confirmed that the addition of elements, improved the hardness property of Fe-based oxide dispersion strengthened alloys.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Magnetocaloric effect in a $Mn_{2}-pyridazine-[Nb(CN)_{8}]$ molecular magnetic sponge
Autorzy:: Zentkova, Maria
Sieklucka, Barbara
Pełka, Robert
Wasiutyński, Tadeusz
Pinkowicz, Dawid
Fitta, Magdalena
Czapla, Mariusz
Bałanda, Maria
Mihalik, Marian
Opis:: A comprehensive study of the magnetocaloric effect (MCE) in the $Mn_{2}-[Nb(CN)_{8}]$ molecular magnet with a two-step magnetic sponge behavior is reported. The structural trans- formations provoked by dehydration bring about an increase in the magnetic ordering temperature ($T_{c}$) from 43 K through to 68 K and up to 98 K. All three phases are soft isotropic ferrimagnets. The change in magnetic entropy in the par- tially and fully dehydrated phases is smaller than that in the “as synthesized” form by a factor of 0.6. The field depen- dence of MCE at $T_{c}$ is consistent with the values of the critical exponents derived from the magnetization data.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 8.

Tytuł:: Double switching of a magnetic coordination framework through intraskeletal molecular rearrangement
Autorzy:: Czapla, Mariusz
Pinkowicz, Dawid
Bałanda, Maria
Oszajca, Marcin
Gaweł, Bartłomiej
Sieklucka, Barbara
Łasocha, Wiesław
Podgajny, Robert
Nitek, Wojciech
Makarewicz, Magdalena
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 9.

Tytuł:: Synthesis and structural characterization of niobium-doped hydroxyapatite ceramics
Autorzy:: Korzeniewski, Wojciech
Witkowska, Agnieszka
Tematy:: structure
nanoceramics
sol-gel method
hydroxyapatite
niobium
mechano-chemical synthesis; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Powiązania:: https://bibliotekanauki.pl/articles/284989.pdf Link otwiera się w nowym oknie
Opis:: Hydroxyapatite (HAp) ceramic materials are consi-dered as one of the most promising implant materials in bone surgery and in dentistry. They exhibit unique biocompatibility, bioactivity, and osteoconductivity, which are the most desirable biomaterial features. However, HAp itself is brittle, has low strength, high degree of crystallinity and low solubility at physiological pH. Doping synthetic HAp with metal ions plays an important role in improving its structural and physico--chemical properties. HAp doped with niobium ions has not been widely investigated so far. However, the results of studies available in the literature show that the synthesized CaO-P2O5-Nb2O5 compounds still show good biocompatibility, very low cytotoxicity and, additionally, they stimulate osteoblast proliferation. Therefore, this study is dedicated to the niobium--doped HAp ceramics obtained by two methods: mechano-chemical synthesis and sol-gel method. Bioceramics chemical composition, morphology, and structure were characterized by means of scanning electron microscopy imaging, BET method, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results indicate that nanoceramics of non-stoichiometric HAp with a clear Ca deficiency on the nanograin surface were obtained. Moreover, it has been observed that the presence of Nb dopants and the synthesis method directly affect unit cell parameters, crystallinity degree, crystallites size, porosity and distribution of niobium in the grain structure. Mechano-chemical synthesis has allowed effective niobium incorporation into the HAp structure, leading to the quite homogeneous Nb distribution in the grain volume. Whereas, Nb-doping by sol-gel method has led to dopants location mainly on the grain surface.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Acidic Corrosion Behaviour of Niobium-Added Welding Overlays Fabricated by Self-Shielded Metal-Cored Wires
Autorzy:: Liu, Dashuang
Wu, Yucheng
Long, Weimin
Wei, Ping
Wang, Rui
Zhou, Wei
Tematy:: acidic corrosion behavior
niobium addition
self-shielded metal-cored wire; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/59110569.pdf Link otwiera się w nowym oknie
Opis:: Both corrosion and abrasion remove materials from some engineering components such as impact coal crusher hammers, pulverizer rings, chute liner, and rolls or molds. Intensive research has been done on improving the wear resistance of high chromium alloys, however, studies into corrosion resistance of high chromium alloys are insufficient. In order to determine the amount of ferroniobium addition in the wire to achieve the best corrosion resistance, and find out the mechanism of ferroniobium enhancing the corrosion resistance of the welding overlays, the high-Cr iron-based welding overlays with different niobium addition were fabricated by using self-made self-shielded metal-cored wires and their acidic corrosion resistance in 3.5 wt.% NaCl solution + 0.01 mol/L HCl solution were investigated by electrochemical corrosion test. The microstructure and corrosion morphology were characterized by OM, SEM, XRD and EDS. The polarization curves and values of Icorr, Ecorr and Rc indicate the corrosion resistance is at the highest with 3.6 wt.% niobium addition, and at the lowest when the niobium addition is 10.8 wt.%. The corrosion of welding overlay occurs in the matrix of microstructure. With the increase of niobium addition from 3.6 wt.% to 10.8 wt.%, the proportion of network eutectic structure in the welding overlay is increased. Up to 10.8 wt.%, the microstructure is transformed from hypereutectic structure into eutectic one, leading to a higher acceleration of corrosion rate. When niobium addition reaches 14.4 wt.%, the welding overlay is transformed into a hypoeutectic structure. The addition of niobium element consumes carbon element in the alloy, which makes the increase of chromium content in the final solidified matrix, leading to an improvement in corrosion resistance.
Dostawca treści:: Biblioteka Nauki

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