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1.
HIMANSHU TRIPATHI AREPALLI SAMPATH KUMAR S P SINGH 《Bulletin of Materials Science》2016,39(2):365-376
The aim of the present investigation was to study the role of Al2O3 in the Li2O–CaO–P2O5–SiO2 bioactive glass for improving the bioactivity and other physico-mechanical properties of glass. A comparative study on structural and physico-mechanical properties and bioactivity of glasses were reported. The structural properties of glasses were investigated by X-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy and the bioactivity of the glasses was evaluated by in vitro test in simulated body fluid (SBF). Density, compressive strength, Vickers hardness and ultrasonic wave velocity of glass samples were measured to investigate physical and mechanical properties. Results indicated that partial molar replacement of Li2O by Al2O3 resulted in a significant increase in mechanical properties of glasses. In vitro studies of samples in SBF had shown that the pH of the solution increased after immersion of samples during the initial stage and then after reaching maxima it decreased with the increase in the immersion time. In vitro test in SBF indicated that the addition of Al2O3 up to 1.5 mol% resulted in an increase in bioactivity where as further addition of Al2O3 caused a decrease in bioactivity of the samples. The biocompatibility of these bioactive glass samples was studied using human osteoblast (MG-63) cell lines. The results obtained suggested that Li2O–CaO–Al2O3–P2O5–SiO2-based bioactive glasses containing alumina would be potential materials for biomedical applications. 相似文献
2.
Rajendra Kumar Singh A. Srinivasan G. P. Kothiyal 《Journal of materials science. Materials in medicine》2009,20(1):147
Magnetic bioglass ceramics (MBC) are being considered for use as thermoseeds in hyperthermia treatment of cancer. While the bioactivity in MBCs is attributed to the formation of the bone minerals such as crystalline apatite, wollastonite, etc. in a physiological environment, the magnetic property arises from the magnetite [Fe3O4] present in these implant materials. A new set of bioglasses with compositions 41CaO · (52 ? x)SiO2 · 4P2O5 · xFe2O3 · 3Na2O (2 ≤ x ≤ 10 mol% Fe2O3) have been prepared by melt quenching method. The as-quenched glasses were then heat treated at 1050°C for 3 h to obtain the glass-ceramics. The structure and microstructure of the samples were characterized using X-ray diffraction and microscopy techniques. X-ray diffraction data revealed the presence of magnetite in the heat treated samples with x ≥ 2 mol% Fe2O3. Room temperature magnetic property of the heat treated samples was investigated using a Vibrating Sample Magnetometer. Field scans up to 20 kOe revealed that the glass ceramic samples had a high saturation magnetization and low coercivity. Room temperature hysteresis cycles were also recorded at 500 Oe to ascertain the magnetic properties at clinically amenable field strengths. The area under the magnetic hysteresis loop is a measure of the heat generated by the MBC. The coercivity of the samples is another important factor for hyperthermia applications. The area under the loop increases with an increase in Fe2O3 molar concentration and the. coercivity decreases with an increase in Fe2O3 molar concentration The evolution of magnetic properties in these MBCs as a function of Fe2O3 molar concentration is discussed and correlated with the amount of magnetite present in them. 相似文献
3.
Sonam Rani Sujata Sanghi Ashish Agarwal Neetu Ahlawat 《Journal of Materials Science》2009,44(21):5781-5787
Lithium ion transport has been studied in bismuth lithium phosphate glasses in the frequency range 20 Hz–1 MHz and in the
temperature range 423–573 K using impedance spectroscopy. The addition of Bi2O3 in Li2O·P2O5 glass is related to the modification of the glass structure and facilitates the Li+ ions migration. The ac and dc conductivities, activation energy of the dc conductivity and relaxation frequency are extracted
from the impedance spectra. Conductivity of the present glass system is found to be ionic in nature. The electrical response
of the glasses has been studied using both conductivity and electric modulus formalisms. A single ‘master curve’ for normalized
plots of all the modulus isotherms observed for a given composition indicates the temperature independence of the dynamic
processes for ions in these glasses. Nearly identical values of activation energy for dc conduction and for conductivity relaxation
time indicate that the ions overcome same energy barrier while conducting and relaxing. 相似文献
4.
Mesoporous bioactive glasses (MBGs) of the CaO–SiO2–P2O5 system containing relatively high P2O5 contents (10–30 mol%) were prepared from a sol–gel. An evaporation-induced self-assembly (EISA) technique was used with poly(ethylene
oxide)-block–poly(propylene oxide)-block–poly(ethylene oxide) (EO20–PO70–EO20, P123) acting as a template. The structural, morphological and textural properties of MBGs were investigated by small-angle
X-ray diffraction (SAXRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and a N2 sorption/desorption technique. SAXRD and TEM results display the reduced long-range ordering of mesopores with increasing
P2O5 content. N2 sorption/desorption analysis shows that all three samples exhibit a type IV isotherm with type H1 hysteresis loops, characteristic
of independent cylindrical slim pore channels and this material has a Barret–Joyner–Halenda (BJH) model pore size of ~4 nm
and BET specific surface area ~430 m2/g. NMR results indicate a more condensed framework for samples with 30 mol% P2O5 than samples with 10 mol% P2O5. For in vitro bioactivity tests where samples were soaked in simulated body fluid (SBF), samples with 30 mol% P2O5 showed higher crystallinity than those with lower P2O5 contents Silicon concentration increased in SBF solution during the soaking period, which indicates MBGs can be degradable
in SBF solution. 相似文献
5.
Aluminium-based metal matrix composite strengthened by in situ Al2O3 and Al3Zr particles were synthesized by powder metallurgy route. Phase analysis by X-ray diffraction and scanning electron microscopy revealed that the reaction between Al and ZrO2 produced Al2O3 and Al3Zr phases in the sintered composites. The hardness of the composite is a strong function of sintering temperature as well as the volume fraction of reinforcements. The dry sliding wear test results clearly indicated that increasing the volume fraction of zirconia particles in the composite improved the wear resistance. Microcutting, ploughing, delamination and oxidation were the main mechanisms of wear. 相似文献
6.
N S VEDEANU I B COZAR R STANESCU R STEFAN D VODNAR O COZAR 《Bulletin of Materials Science》2016,39(3):697-702
The xV2O(1?x)[0.8 P2O5 ? 0.2 K2O] glass system with 0 ≤ x ≤ 50 mol% was prepared and the structural changes induced in these glasses by increasing the vanadium oxide content were investigated by IR and ESR spectroscopies. The dual behaviour role of V2O5 oxide, as network modifier (for x ≤ 10 mol%) and the network former (x ≥ 20 mol%), as a consequence of phosphate network depolymerization and P–O–V and V–O–V linkages appearance was also highlighted. The antibacterial effect of the glasses with x ≤ 20 mol% V2O5 content was tested by optical density (OD) measurements. A linear correlation between the amount of vanadium and the antibacterial effect was evidenced. 相似文献
7.
The possibility of using phytic acid as a precursor to synthesize CaO–P2O5–SiO2 glasses by sol–gel method has been explored and the pseudo ternary phase diagram has been established. It was shown that
gel-glasses over a broader range of compositions could be prepared compared to other phosphorus precursors or melt-quenching
method. Furthermore, phytic acid was found to assist calcium being incorporated into glass networks. In vitro tests in simulated
body fluid (SBF) were performed on the above gel–glasses and it was found that they were bioactive over a much broader compositional
range especially at high phosphate content, thus enabling one to design bioactive materials with various degradation rates
by adjusting the phosphate content. 相似文献
8.
Six glasses of the chemical composition 10ZnO–xPbO–(90−x) P2O5 were prepared. With an increase in PbO content a non-monotonous step like increase in the density, in the glass transition
temperature, and in the refractive index was observed. From the Raman and IR spectra studied the evidence is given for the
phosphate network depolymerization as PbO content increases. Increase in PbO content leads also to an increase in refractive
index (n) up to n = 1.74, for x = 55, and to an increase in the glass transition temperature (T
g) from T
g = 270 °C (x = 30) to T
g = 360 °C (x = 55).
相似文献
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9.
Haiyu Wang Hua Su Yuanming Lai Huaiwu Zhang Yuanxun Li Xiaoli Tang 《Journal of Materials Science: Materials in Electronics》2017,28(19):14190-14194
In this paper, the effects of Li2O–B2O3–Bi2O3–SiO2 (LBBS) glass on the phase formation, sintering characteristic, the microstructure and microwave dielectric properties of temperature-stable (Mg0.95Co0.05)2TiO4–Li2TiO3 ceramics were investigated. (Mg0.95Co0.05)2TiO4–Li2TiO3 powders were obtained by using the traditional solid-state process. A small amount of LBBS doping can effectively reduce sintering temperature and promote the densification of the ceramics. X-ray diffraction analysis revealed not only the primary phase (Mg·Co)2TiO4 associated with Li2TiO3 minor phase but also a third phase (Mg·Co)TiO3. The dielectric constant and Qf values vary with the doping amount of LBBS and sintering temperatures. With the compensation of the positive temperature coefficient (τ f ) of Li2TiO3 and the negative τ f of (Mg0.95Co0.05)2TiO4, the τ f of the specimens fluctuates around zero. The (Mg0.95Co0.05)2TiO4 ceramic with 2.5 wt% LBBS addition and sintering at 900?°C for 4 h exhibited excellent microwave dielectric properties: ? r ?=?19.076, Qf?=?126100 GHz, and τ f ?=?0.98 ppm/°C. 相似文献
10.
xV2O5·(100 − x)[0.7P2O5·0.3CaO] glass system was obtained for 0 ≤ x ≤ 35 mol% V2O5. In order to obtain information regarding their structure, several techniques such as X-Ray diffraction, FT-IR, and EPR spectroscopies
were used. X-Ray diffraction patterns of investigated samples are characteristic of vitreous solids. FT-IR spectra of 0.7P2O5·0.3CaO glass matrix and its deconvolution show the presence in the glass structure of all structural units characteristic
to P2O5. Their number are increasing for x ≤ 3 mol% V2O5 then, for higher content of vanadium ions, the number of phosphate structural units are decreasing leading to a depolymerization
of the structure. The structural units characteristic to V2O5 were not evidenced but their contribution to the glass structure can be clearly observed. EPR revealed a well resolved hyperfine
structure (hfs) typical for vanadyl ions in a C4v symmetry for x ≤ 3 mol% V2O5. For 5 < x < 20 mol% V2O5 the spectra show a superposition of two EPR signals one due to a hfs structure and another consisting of a broad line typical
for associated V4+–V4+ ions. For x ≥ 20 mol% V2O5 only the broad line can be observed. The composition dependence of the line-width suggests the presence of dipole–dipole
interaction between vanadium ions up to x ≤ 5 mol% V2O5 and superexchange interactions between vanadium ions for x > 5 mol% V2O5. 相似文献
11.
X. H. Zheng X. C. Jiang D. P. Tang C. Zhang 《Journal of Materials Science: Materials in Electronics》2011,22(7):781-784
CaO–SrO–Li2O–Ln2O3–TiO2 ceramics were prepared by solid state reaction method, where Ln2O3 consists of equal proportions of Nd2O3 and Sm2O3. Dielectric properties and crystal structure were investigated with respect to the content of TiO2. Single phase with an orthorhombic perovskites structure was formed within the composition range of investigation. The frequency
dependence of dielectric properties of the present ceramics was extensively investigated. Dielectric constant was less sensitive
to frequency. However, dielectric loss and temperature coefficients were both very sensitive to frequency and gradually decreased
with increasing frequency, such as the variation was more than ten times between 1 MHz and several GHz. The relationship between
the temperature coefficient and dielectric loss was also discussed at different frequencies. And the mechanism of the frequency
dependence was discussed in term of the role of Li ions. 相似文献
12.
The capability of BaO–ZnO–B2O3–P2O5 glass in hosting various ceramic fillers (up to 20 mass% of Al2O3, TiO2, and ZnO) has been investigated. All the investigated filler-added glasses have demonstrated a reasonable densification at
550 °C to form stable ceramic filler-glass composites. Modifications of the thermophysical properties, such as coefficient
of thermal expansion (CTE), glass transition temperature, and dilatometric softening temperature, by the addition of the fillers
have been investigated and correlated to phase and microstructural evolution. The CTE of the fabricated composites with varying
filler addition is well correlated with theoretical predictions based on the Turner equation considering the modification
by phase evolution, which indicates the thermal property tuning potential of the BZBP-based glass composites for application
to barrier ribs of plasma display panels. 相似文献
13.
Semih Seyyidoğlu Macit Özenbaş Necmeddin Yazıcı Ayşen Yılmaz 《Journal of Materials Science》2007,42(15):6453-6463
In this study, ZrP2O7 was synthesized by the solid state reaction of ZrO2 and NH4H2PO4 at 900 °C. Then, in set 1; 10, 5, 1, 0.5, 0.1, 0.05, 0.03% previously prepared Sr2P2O7 were doped into ZrP2O7, and Sr2P2O7 slightly affect the unit cell parameter of cubic ZrP2O7 (a = 8.248(6)–8.233(8) Å). The reverse of this process was also applied to Sr2P2O7 system (set 2). ZrP2O7 changes the unit cell parameters of orthorhombic Sr2P2O7 in between a = 8.909(5)–8.877(5) Å, b = 13.163(3)–13.12(1) Å, and c = 5.403(2)–5.386(4) Å. Analysis of the vibrations of the P2O 7 4? ion and approximate band assignments for IR and Raman spectra are also reported in this work. Some coincidences in infrared and Raman spectra both sets were found and strong P–O–P bands were observed. Surface morphology, EDX analysis, and thermoluminescence properties of both sets were given the first time in this paper. 相似文献
14.
The thermodynamics and kinetics of hydrogen absorption–desorption of nfTa2O5–Mg–MgH2—composite (nf stands for nano-flakes) have been studied. The nfTa2O5–Mg composite could absorb hydrogen at room temperature (17 °C). The hydrogen desorption of nfTa2O5–MgH2 composite starts at 200 °C. The remarkably improved hydrogen absorption–desorption of catalyzed Mg–MgH2 could be attributed to the nano-engineered surface by nfTa2O5. The enthalpies of hydrogen absorption–desorption were found to be 80 ± 2, and 76 ± 3 kJ/mol respectively. The activation energy of hydrogen absorption was evaluated as 49 ± 5 kJ/mol which is same as the energy barrier for diffusion of hydrogen in Mg matrix. The apparent activation of hydrogen desorption of nfTa2O5–MgH2 was found to be 74 ± 7 kJ/mol. The nfTa2O5–MgH2 composite has shown cyclic stability up to fifty hydrogen absorption–desorption without significant changes in the kinetics and hydrogen storage capacity. 相似文献
15.
Bin Li Wenqin Luo Yongya Wang Yanhui Zhang Haiyan Wu 《Journal of Materials Science》2018,53(11):8030-8038
The glass and glass ceramics containing SiO2–CaO–Fe2O3–P2O5 were prepared by sol–gel method. The influence of the Fe contents on the crystallization and local structure of the glass and glass ceramics was systematically investigated. The crystal structure of the glass ceramics was identified by XRD characterization. Hematite phase can be precipitated from the glass matrix in all glass ceramics with various Fe contents, and the crystallographic parameters of hematite were determined by XRD Rietveld refinement. The crystallization kinetics of the glasses was investigated in detail. Relative low activation energies were obtained at low Fe contents. The local structure evolution of the glass and glass ceramics has been studied in-depth by means of FTIR and Mössbauer spectroscopy. Fe element is present both as network former and network modifier which significantly influenced the crystallization activation energies of the glasses. The results of this work may be of great significance for the material design and practical applications of bioactive magnetic glass ceramics for hyperthermia. 相似文献
16.
Shaaban M. Salem E. M. Antar A. G. Mostafa S. M. Salem S. A. El-badry 《Journal of Materials Science》2011,46(5):1295-1304
(10Li2O–20GeO2–30ZnO–(40-x)Bi2O3–xFe2O3 where x = 0.0, 3, 6, and 9 mol%) glasses were prepared. A number of studies, viz. density, differential thermal analysis, FT-IR spectra,
DC and AC conductivities, and dielectric properties (constant ε′, loss tan δ, AC conductivity, σ
ac, over a wide range of frequency and temperature) of these glasses were carried out as a function of iron ion concentration.
The analysis of the results indicate that, the density and molar volume decrease with an increasing of iron content indicates
structural changes of the glass matrix. The glass transition temperature T
g and onset of crystallization temperature T
x increase with the variation of concentration of Fe2O3 referred to the growth in the network connectivity in this concentration range, while glass-forming ability parameter ΔT decrease with increase Fe2O3 content, indicates an increasing concentration of iron ions that take part in the network-modifying positions. The FT-IR
spectra evidenced that the main structural units are BiO3, BiO6, ZnO4, GeO4, and GeO6. The structural changes observed by varying the Fe2O3 content in these glasses and evidenced by FTIR investigation suggest that the iron ions play a network modifier role in these
glasses while Bi2O3, GeO2, and ZnO play the role of network formers. The temperature dependence of DC and AC conductivities at different frequencies
was analyzed using Mott’s small polaron hopping model and, the high temperature activation energies have been estimated and
discussed. The dielectric constant and dielectric loss increased with increase in temperature and Fe2O3 content. 相似文献
17.
Tulyaganov DU Agathopoulos S Valerio P Balamurugan A Saranti A Karakassides MA Ferreira JM 《Journal of materials science. Materials in medicine》2011,22(2):217-227
New compositions of bioactive glasses are proposed in the CaO–MgO–SiO2–Na2O–P2O5–CaF2 system. Mineralization tests with immersion of the investigated glasses in simulated body fluid (SBF) at 37°C showed that
the glasses favour the surface formation of hydroxyapatite (HA) from the early stages of the experiments. In the case of daily
renewable SBF, monetite (CaHPO4) formation competed with the formation of HA. The influence of structural features of the glasses on their mineralization
(bioactivity) performance is discussed. Preliminary in vitro experiments with osteoblasts’ cell-cultures showed that the glasses
are biocompatible and there is no evidence of toxicity. Sintering and devitrification studies of glass powder compacts were
also performed. Glass-ceramics with attractive properties were obtained after heat treatment of the glasses at relatively
low temperatures (up to 850°C). 相似文献
18.
D. S. Lipatov A. N. Guryanov M. V. Yashkov M. M. Bubnov M. E. Likhachev 《Inorganic Materials》2018,54(3):276-282
An all-vapor phase MCVD process has been proposed for the fabrication of fiber preforms with a Yb2O3–Al2O3–P2O5–SiO2 multicomponent glass core. We have investigated the tubular preform collapse into a rod and demonstrated approaches capable of preventing P2O5 losses in the central part of the core during the collapse process. Preforms with a flat, perfect step-index profile have been fabricated. 相似文献
19.
Xiaoling Ma Huibing He Ya Sun Youxiang Zhang 《Journal of Materials Science: Materials in Electronics》2017,28(22):16665-16671
Li1.2Mn0.54Co0.13Ni0.13O2 was synthesized by sol–gel method at 700, 800, 900 and 1000 °C, respectively, characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and measured as the cathode materials for lithium-ion batteries (LIBs). After their performances have been compared, 800 °C was considered as the optimum synthesis temperature for Li1.2Mn0.54Co0.13Ni0.13O2 as the cathode materials for LIBs. When charge–discharged at 20 mA g?1 in a voltage window of 2.0–4.8 V, the Li1.2Mn0.54Co0.13Ni0.13O2 synthesized at 800 °C (LMNCO-800) showed charge and discharge capacities of 376.2 and 276.3 mAh g?1, respectively, with irreversible capacity of 99.9 mAh g?1 and Coulombic efficiency of 73.4%, in the first charge–discharge cycle. The discharge capacity was 239.0 mAh g?1 in the 50th charge–discharge cycle, with capacity retention of 86.6%. The LMNCO-800 also showed superior high-rate performances. When cycled at the rates of 0.5, 1, 2 and 5 C rate (1 C?=?200 mA g?1), the discharge capacities of the Li1.2Mn0.54Co0.13Ni0.13O2 can reach 241, 171, 150 and 110 mAh g?1, respectively. When characterized with high-resolution transmission electron microscopy (TEM), nanodomains with two different structures can be found in LMNCO-800, with some nanodomains showing monoclinic Li2MnO3 structure and the other nanodomains showing hexagonal LiMO2 structure. 相似文献
20.
Reinhold Melcher Nahum Travitzky Cordt Zollfrank Peter Greil 《Journal of Materials Science》2011,46(5):1203-1210
Porous alumina preforms were fabricated by indirect 3D printing using a blend of alumina and dextrin as a precursor material.
The bimodal granulate powder distribution with a bed density of 0.8 g/cm3 was increased to 1.4 g/cm3 by overprinting. The porosity of the sintered bodies was controlled by adjusting the printing liquid to precursor powder
ratio in the range of 33–44 vol%. The green bodies exhibited bending strengths between 4 and 55 MPa. An isotropic linear shrinkage
of ~17% was obtained due to dextrin decomposition and Al2O3 sintering at 1600 °C. Post-pressureless infiltration of the sintered preforms with a Cu–O alloy at 1300 °C for 1.5 h led
to the formation of a dense Al2O3/Cu–O interpenetrating phase composite (IPC). X-ray analysis of the fabricated composites showed the presence of α-Al2O3, Cu and Cu2O. CuAl2O4 spinel was not observed at the grain boundaries during HRTEM examination. The Al2O3/Cu–O interpenetrating phase composite revealed a fracture toughness of 5.5 ± 0.3 MPam1/2 and a bending strength of 236 ± 32 MPa. In order to demonstrate technological capability of this approach, complex-shaped
bodies were fabricated. 相似文献