فصلنامه سرامیک ایران
سال نوزدهم شماره 1 (پیاپی 73، بهار 1402)

Copper oxide is obtained by various methods, including electrolysis, recovery of copper salts or copper oxide, thermal oxidation and hydrothermal treatment. Electrochemical method is very interesting due to its low cost, low temperature, ease of operation, high purity and compatibility with the environment. In this research, the effects of NaCl, Na2SO4 and CTAB (cetyltrimethylammonium bromide, C19H42BrN) electrolytes on the synthesis of Cu2O nanoparticles by electrochemical method were investigated. Changes of NaCl in three values of 58.5, 117 and 175.5 (g/lit); changes of Na2SO4 in concentrations of 24, 32 and 48 (g/lit) and changes of CTAB in the range of 2, 4, 6 and 15 (g/lit) were selected. The current density and temperature were fixed and equal to 0.4 (amps/cm2) and 70°C, respectively, and the fixed distance between the cathode and the anode was considered to be 2.5 cm. FESEM and XRD were used to observe the morphology of the samples and identify the composition and determine the particle size. The results showed that by increasing the concentration of NaCl and Na2SO4 electrolyte, the purity of Cu2O increased. The size of Cu2O crystals was below 100 nm and the formation of Cu2O was polycrystalline. Also, high concentration of NaCl gave better results compared to Na2SO4. CTAB effectively prevents the growth of Cu2O nanoparticles and the particle size was inversely related to the increase of CTAB. The best result was obtained in the sample with 4 (g/lit) CTAB and 175(g/lit)NaCl. Cu2O nanoparticles with high purity and crystal size of 27.87 nm were produced.

Zinc oxide (ZnO) ceramic is of interest due to its unique properties such as semiconductor, photocatalytic, biocompatibility and high dielectric constant. This research investigates the effect of annealing temperature on the dielectric properties, microstructure, and electrical resistance of ZnO ceramics. ZnO samples, after sintering at 1250°C, were annealed at temperatures of 850, 950, and 1050°C for 4 hours. X-ray diffraction analysis results showed that annealing reduces microstrain in the samples and increases the size of crystallite. No significant differences were observed in the size and morphology of the grains in the annealed and non-annealed samples. Annealing resulted in a significant decrease in the dielectric constant and dielectric loss of ZnO ceramics. The sample annealed at 950°C had the lowest dielectric constant and dielectric loss. Annealing at 950°C reduced the dielectric constant of ZnO ceramic from 111,000 to 35,000 and the dielectric loss from 22 to 6, measured at 1 kHz. The reduction in electrical losses may be attributed to the decrease in microstrain and the increase in crystallite size. The conductivity of annealed samples was lower than ZnO ceramic. Annealing caused an increase in the electrical resistance of the grain and grain boundary of ZnO ceramics. A significant increase in the electrical resistance of the grain boundary may indicate a decrease in the concentration of oxygen vacancies, which leads to a decrease in the dielectric constant of ZnO ceramics.

Iron oxide nanoparticles have been gaining much attention lately due to their magnetic properties and biocompatibility. This research focused on investigating the properties and synthesis of iron oxide nanoparticles that have been substituted with zinc ZnxFe3-xO4 (x= 0.0, 0.2, 0.4, 0.6)  using the hydrothermal method. The synthesized samples were analyzed using X-ray diffraction and found that they have a space group of fd3m. The crystal size of the samples was found to be smaller than 20 nm. Vibrating sample magnetic analysis (VSM) was used to determine the magnetic behavior of the nanoparticles. The analysis showed that the nanoparticles exhibited superparamagnetism. In addition, the saturation magnetization values of the nanoparticles for samples with x = 0, 0.2, 0.4, and 0.6 were 44.10, 49.09, 43.51, and 48.07 emu/g, respectively. The microstructure and grain size of magnetic nanoparticles were analyzed using a field emission electron microscope (FESEM). The FESEM images revealed that the majority of the grains are spherical and have uniform distribution. The average grain size for the sample ranges between 10 and 30 nm. Based on these results, it can be concluded that these particles are suitable for use in medical and catalytic applications.

In recent years, there has been a significant interest in lanthanum-based perovskites due . Lanthanum strontium manganite (LSMO) is one of the most well-known materials. In this research, the synthesis and investigation of the effect of oleic acid on the structural and magnetic properties of La0.7Sr0.3MnO3 nanoparticles by the combustion sol-gel method is discussed. The structural and magnetic properties of the prepared samples were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), magnetic properties analysis (VSM), and field emission electron microscopy (FESEM). In the XRD study, it was found that the crystal structure of the samples is hexagonal. Also, the average crystal size in the samples increased from 18 nm to about 33 nm as a result of adding oleic acid. The images obtained from FESEM show that the presence of oleic acid in the synthesis of nanoparticles caused it to affect the shape of the particles as a surface layer. Synthesized nanoparticles have a particle size between 20-100 nm, and with the increase of oleic acid, the particle size becomes more than 100 nm. FTIR spectroscopy revealed the effective bonding between LSMO nanoparticles and oleic acid, based on these results, it clearly shows the presence of oleic acid molecules on the surface of magnetic particles. In the investigation of magnetic properties, it was found that the presence of non-magnetic sodium oleate surface layer, which due to the addition of oleic acid on nanoparticles, the saturation magnetization value decreased from 38.55 emu/g to 28.46 emu/g.

Hard tissues in the body consist of intricate three-dimensional composites, wherein approximately 30% constitutes collagen fibers, 60% mineral reinforcing particles, and 10% water. The mineral copounds of Natural bone tissues, such as calcium phosphate materials play a fundamental role in enhancing strength,hardness, and pressure resilience. The use of calcium phosphate bioceramics as bone grafts, such as Whitlockite(Ca18Mg2(HPO4)2(PO4)12), offers a promising method for treating bone defects due to its close chemical, biological, and crystalline resemblance to natural hard tissue. Also, Its biocompatibility, functionality, stability under acidic pH, negative surface charge, osteo inductivity and osteo conductivity, and maintaining Mg ions in their crystal structure make it an ideal bone substitute as compared to the other Ca-P bio ceramics.
This study aims to synthesize Whitlockite nanopowders using the chemical precipitation method with the precursers Mg(OH)2, Ca(OH)2, and H3PO4, and investigate the effects of pH, temperature, and Ca/Mg and Ca/P ions  ratios on the synthesized Whitlockite. Additionally, the impact of varying temperature and pH on the reactions during Whitlockite synthesis is explored. To characterize the synthesized powders, XRD, FTIR, SEM, and EDS analyses were employed. The results revealed that optimizing pH to 5 and temperature to 80°C yielded  Whitlockite with a crystal grain size of 61 nm. Increasing the ratio of (Mg2+ / Ca2+) ions concentrations in the reaction solution resulted in the formation of the Whitlockite phase and the magnesium phosphate phase (MgHPO4), while decreasing that ratio produced the monetite phase (CaHPO4) or dicalcium phosphate dihydrate (CaHPO4.2(H2O)). Furthermore, at 70°C, the formation of hydroxyapatite initially occurred, however the reaction favored the transformation into the more stable Whitlockite phase as pH values became acidic. In conclusion, this research highlights the significance of chemical precipitation for Whitlockite synthesis, providing valuable insights into the influence of pH, temperature, and ion ratios on the resulting crystalline phases. The findings contribute to a deeper understanding of the potential applications of Whitlockite as a bioceramic material for bone defects treatment.

MAX phase materials are a new family of three-layer carbide and nitride compounds, represented by the general formula Mn+1AXn, where n = 1-3, M stands for primary transition metals, and A is the element of group A of the periodic table and X is nitrogen or carbon. In recent years, new research has focused on the MAX phase, as it became possible to obtain MXene through their selective etching and removal of the A element. In this review, the development of the MAX phase and its characteristics are introduced. In the next step, the structure, morphology, electronic structure, and diversity of the MAX phase are described and finally, different preparation methods and applications related to MAX phase films, bulk, and powder materials are introduced according to current preparation technologies.