Nguyen Vu Uyen Nhi, Doan Duong Xuan Thuy, Do Quang Minh, Kieu Do Trung Kien,
Volume 20, Issue 3 (9-2023)
Abstract
This paper introduces a method for producing red copper glaze by adding copper oxide (CuO) and silicon carbide (SiC) additives to the base glaze. SiC created a reducing environment in situ and allowed the glaze to be sintered in an oxidizing furnace environment. Nanocrystals are the determinants of the red color of the glaze. The CuO reduction reaction temperature range of SiC produces a reducing environment in the glaze as detected by the method (DSC). The functional group and phase of nanocrystals were determined by Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) spectroscopy.
Bijan Eftekhari Yekta, Omid Banapour Ghafari,
Volume 20, Issue 4 (12-2023)
Abstract
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.
Hamed Nadimi, Hossein Sarpoolaky, Mansour Soltanieh,
Volume 20, Issue 4 (12-2023)
Abstract
In the present investigation, an attempt was made to evaluate the dissolution behavior of Ti in molten KCl-LiCl. The X-ray diffraction (XRD) pattern of heated Ti plate at 800 oC for 4 h without carbon black in molten salt revealed that TiCl3 formation was feasible. For more assurance, Ti plate was heated at 950 oC for 4 h in the presence of carbon black to identify synthesized TiC. Transmission electron microscope (TEM) and scanning electron microscope (SEM) images from precursors and the final product showed that nano-crystalline TiC formation from coarse Ti particles was almost impossible without Ti dissolution. Thermodynamics calculations using Factsage software proved that it was possible to form various TiClx compounds. The TiC formation mechanism can be discussed in two possible ways: a reaction between Ti ion and carbon black for synthesizing TiC (direct) and a reaction between TiCl4 and carbon black led to indirect TiC synthesis. Elemental mapping using energy dispersive X-ray spectroscope (EDS) indicated that up to 815 oC, chlorine existed in the map.
Ahad Saeidi, Sara Banijamali, Mojgan Heydari,
Volume 21, Issue 2 (6-2024)
Abstract
This study explores the fabrication, structural analysis, and cytocompatibility of cobalt-doped bioactive glass scaffolds for potential applications in bone tissue engineering. A specific glass composition modified from Hench's original formulation was melted, quenched, and ground to an average particle size of 10 μm. The resulting amorphous powder underwent controlled sintering to form green bodies and was extensively characterized using simultaneous differential thermal analysis (DTA), Raman spectroscopy, and Fourier Transform Infrared analysis (FTIR). After mixing with a resin and a dispersant, the composite was used in digital light processing (DLP) 3D printing to construct scaffolds with interconnected macropores. Thermal post-treatment of 3D printed scaffolds, including debinding (Removing the binder that used for shaping) and sintering, was optimized based on thermogravimetric analysis (TG) and the microstructure was examined using FE-SEM and XRD. In vitro bioactivity was assessed by immersion in simulated body fluid (SBF), while cytocompatibility with MC3T3 cells was evaluated through SEM following a series of ethanol dehydrations. The study validates the fabrication of bioactive glass scaffolds with recognized structural and morphological properties, establishing the effects of cobalt doping on glass behavior and its implications for tissue engineering scaffolds. Results show, Low cobalt levels modify the glass network and reduce its Tg to 529 oC, while higher concentrations enhance the structure in point of its connectivity. XRD results shows all prepared glasses are amorphous nature, and DTA suggests a concentration-dependent Tg relationship. Spectroscopy indicates potential Si-O-Co bonding and effects on SiO2 polymerization. Cobalt's nucleating role promotes crystalline phases, enhancing bioactivity seen in rapid CHA layer formation in SBF, advancing the prospects for bone tissue engineering materials.
Mahnaz Dashti, Saeid Baghshahi, Arman Sedghi, Hoda Nourmohammadi,
Volume 21, Issue 3 (9-2024)
Abstract
Abstract
The power line insulators are permanently exposed to various environmental pollutants such as dust and fine particles. This may lead to flashovers and therefore widespread power blackouts and heavy economic damage. One way to overcome this problem is to make the insulator surface superhydrophobic. In this research, the superhydrophobic properties of the insulators were improved by applying room-temperature cured composite coatings consisting of epoxy and hydrophobic nano-silica particles. Either octadecyl trichlorosilane (ODTS) or hexamethyldisilazane (HMDS) was used to coat the silica nanoparticles and make them hydrophobic. Then, the hydrophobic silica was added to a mixture of epoxy resin and hardener. The suspension was applied on the surfaces of a commercial porcelain insulator and cold cured at ambient temperature. The coating increased the water contact angle from 50° to 149°. Even after 244 h exposure to the UV light, the samples preserved their hydrophobic properties. The adhesion of the coating was rated as 4B according to the ASTM D3359 standard. The coating decreased the leakage current by 40% and increased the breakdown voltage by 86% compared to the uncoated sample and showed promise for making power line insulators self-cleaning.
