Iranian Journal of Materials Science and Engineering

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Abstract: The application of inexpensive materials such as copper, zinc, lead, iron and steel slag in manufacturing of glass and glass-ceramic products in construction industry, lining materials as anti-corrosion and anti-abrasion coatings in metals and etc, has led to considerable progress in glass technology in recent years. The composition of slag glass-ceramics is mainly located in the SiO2-Al2O3-CaO-MgO system, in which one of the most important problems is the lack of bulk crystallization. To resolve the above-mentioned problem, the crystallization behavior of various compositions containing different nucleating agents Cr2O3 , Fe2O3 and TiO2 in the single, double and triple forms were studied by differential thermal analysis (DTA).The precipitated crystalline phases was determined by the X-ray diffractometry and the micro-structural analysis was studies using the SEM micrographs. The three point bending strength, micro-hardness and the chemical resistance of the best composition were determined. According to the results, the resulted glassceramic had a better specification than the stoneware floor tiles and the porcelain one, which are considered as the two important competitors for it.

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Abstract:Some types of glass and glass ceramics have a great potential for making bone tissue engineering scaffolds, drug carrier and bone cements as they can bond to host bone, stimulate bone cells toward osteogenesis, and resorb at the same time as the bone is repaired. Calcium phosphate glass ceramics have very attractive properties that allow them to use in bone tissue engineering. Calcium phosphate glasses could be used for the fabrication of resorbable constructs, with controlled biodegradability. This work was investigated crystallization and sinterability of biodegradable glass ceramics in the CaO–P2O5–Na2O–TiO2 system using differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Sinterability of the glasses also was investigated by measurement of sintering parameters. Different thermal treatments were applied to control the degree of devitrification of glasses. In the developed glass ceramics Ca2P2O7 were the first phase to precipitate in the mother glass structure, followed by Ca(PO3)2 and TiP2O7 at elevated temperature. Ca2P2O7 and Ca(PO3)2 seem to have a very positive effect in bone formation in vivo. It is therefore expected that glass ceramics understudy have good potential to be used for bone regeneration applications

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The effect of titanium dioxide addition on bonding strength of CaO-P2O5 -Na 2O-TiO2glass-ceramic system was investigated as a coating on titanium substrate. Thus, different amounts of TiO2 (2, 3.5 and 5mol %) were added to the base glass batch composition. The prepared glaze slips were applied on the substrate by dip coating method, dried and then heat treated at various temperatures. After that, bonding strength of the glass- substrates was determined via shear stress testing method. The de-bonded interfaces were analyzed by scanning electron microscopy (SEM). According to these results, the 5 mol% TiO 2 containing coating showed the best bonding strength, comparing with the other coatings. The bioactivity of the coated samples was investigated by soaking them in simulated body fluid (SBF). The surface of the samples was studied using SEM and X-Ray microprobe and it was observed that an apatite layer was grown on their surface

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This study focuses on the physical, magnetic, biological and antibacterial behaviour of cobalt-doped HAp powder samples. Pure and Cobalt- doped HAp nanoparticles were synthesized by hydrothermal method. Calcium nitrate, di- ammonium hydrogen phosphate and cobalt nitrate were used as precursor materials.  The synthesized powders were characterized using x-ray diffraction pattern (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), Raman spectroscopy as well as MTT assay and cell adhesion test. Disc diffusion method was used to investigate antibacterial activity of the samples. The results confirmed the substitution of Ca by Co ions in the HAp lattice. In addition, this substitution induced size reduction and morphology change in HAp particles. All cobalt substituted HAp powder samples displayed paramagnetic properties, as opposed to the diamagnetic behaviour observed in the pure HAp samples. In addition, these nanoparticles exhibited cell adhesion, biocompatibility and antibacterial activity against S.aureus bacteria.
This study focuses on the physical, magnetic, biological and antibacterial behaviour of cobalt-doped HAp powder samples. Pure and Cobalt- doped HAp nanoparticles were synthesized by hydrothermal method. Calcium nitrate, di- ammonium hydrogen phosphate and cobalt nitrate were used as precursor materials.  The synthesized powders were characterized using x-ray diffraction pattern (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), Raman spectroscopy as well as MTT assay and cell adhesion test. Disc diffusion method was used to investigate antibacterial activity of the samples. The results confirmed the substitution of Ca by Co ions in the HAp lattice. In addition, this substitution induced size reduction and morphology change in HAp particles. All cobalt substituted HAp powder samples displayed paramagnetic properties, as opposed to the diamagnetic behaviour observed in the pure HAp samples. In addition, these nanoparticles exhibited cell adhesion, biocompatibility and antibacterial activity against S.aureus bacteria.

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Strong glass-ceramic foams with a compressive strength of 20 MPa were prepared by adding various amounts of Fe₂O₃ to a soda lime-based glass composition, and SiC as a foaming agent. The foams were prepared by firing the compacted samples in the range of 750–950°C for different soaking times. The crystallization behavior of the samples was investigated by Simultaneous Thermal Analysis (STA), Scanning Electron Microscope, and X-Ray Diffractometer (XRD). Based on the results, solid solutions of pyroxene groups were crystallized by the surface mechanism, between 730˚C and 900˚C during the firing of the specimens, and their amounts increases with increasing of the added iron oxide. Besides, we found that Fe₂O₃ neither acts as a nucleant for pyroxene nor as an oxidizer for SiC. The results also showed that the compressive strength as well as the crystallization behavior of the foams was influenced by the presence of the SiC particles.

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Glasses in the B₂O₃-Li₂ (O, Cl₂, I₂) system were prepared through the conventional melt-quenching method. Then, the conductivity of the molten and glassy states of these compositions was evaluated. Furthermore, the thermal and crystallization behavior of the glasses was determined using simultaneous thermal analysis (STA) and X-ray diffractometry (XRD). The electrical conductivity of the melts was measured at temperatures ranging from 863 to 973 K, and the activation energy of the samples was calculated using the data obtained from ion conduction in the molten state and found to be in the vicinity of 32 kcal/mol. In glassy states, electrical conductivity was also measured. To determine this property, the electrochemical impedance spectroscopy method (EIS) was used. In the molten state, temperature played an important role in the ion conductivity; however, at lower temperatures, other factors became important. Based on the results, the addition of LiI and LiCl to the B₂O₃-Li₂O base glass system (75 B₂O₃, 10 Li₂O, 7.5 LiI, 7.5 LiCl) (mol%) increases the ionic conductivity of the glass from 3.2 10^-8 S.cm^-1 to 1.4 10^-7 S.cm^-1 at 300 K.