Phase In X-ray Diffraction Pattern Research Articles

Effect of Thermal Treatment on Physico-Chemical Properties of White Mineral Trioxide Aggregate Synthesized from Limestone Precipitate Calcium Carbonate

This study reports the preparation of white mineral trioxide aggregate (WMTA) using precipitate calcium carbonate (PCC) by sol-gel method at various thermal treatments 900, 1100, and 1300 °C. The composition of WMTA included PCC (55% CaO), C6H16O3Si-TEOS (21% SiO2), Al(NO3)3⋅9H2O (2% Al2O3), and Bi2O3. WMTA 1100 with the highest purity was proven by the presence of C3S, C3A, and α-Bi2O3 phase in X-ray diffraction patterns. Results show that based on the SEM image WMTA 1100 formed a smaller crystal agglomeration (6-8 µm) and FTIR analysis found Bi-O (BiO3) vibration in Bi2O3 at 1100 and 950 cm-1, a characteristic of the β-C2S phase. The radiopacity value of WMTA 1100 resembles ProRoot MTA, namely 6.86±0.36 millimeters of aluminum (mm Al). WMTA 1100 gives the highest compressive strength, smallest solubility, highest pH, and calcium levels in comparison to WMTA 900 and WMTA 1300.

The bioactivities of prepared Ti, Zn, TiO2, ZnO and Al2O3 nanoparticles by rapid breakdown anodization technique

Ti and Zn content have essential role in determining the characters of many biomedical alloys and studying their bioactivities is an important issue. These elements with TiO2, ZnO and Al2O3 oxides were synthesized in nano sizes by Rapid Breakdown Anodization (RBA) method. Electrophoretic deposition (EPD) technique was utilized to deposit produced powders on their corresponding metal sheets. Bioactivity tests (BACT) of these materials were accomplished by soaking them inside simulated body fluid (SBF) solution for one month to detect the constructions of apatite layers on their surfaces. X-Ray Diffraction (XRD) and scanning electron microscope (SEM) analysis were utilized to record the bioactivities of these samples. After BACT Hydroxyapatite (HAp) phase was recorded in XRD patterns of Ti, TiO2 and Zn, ZnO. Also SEM images of these materials showed the creations of new HAp particles. These two tests referred to the bioactivities of these nanoparticles. There were no peaks belonged to HAp phase in XRD pattern of Al2O3. This refers to absence of bioactivity for this oxide. Energy dispersive X-ray spectroscopy (EDS) was used to measure weights and atomic percentages of elements before and after BACT. Molar Ca/P ratio was calculated for all samples, their values were 0.97, 1.277 and 0.86 for Ti,TiO2; Zn, ZnO and Al2O3 nanoparticles respectively.

Chemical conversion of a solid body of the composite gypsum/polyhydroxybutyrate in hydroxyapatite/polyhydroxybutyrate

Abstract The transformation of the gypsum into hydroxyapatite allows added value to this raw material, because the ceramic obtained has a high commercial value in relation to gypsum, while the polymer adds biocompatibility and bioactivity properties to the biocomposite. Thus, hydroxyapatite/polyhydroxybutyrate composites were prepared from the gypsum/polyhydroxybutyrate, using a 10% mass ratio of the polymer. The material was obtained by means of a chemical conversion carried out in a solution of ammonium hydrogen phosphate (0.5 mol.L-1) and alkaline medium (ammonium hydroxide 6.0 mol.L-1) for pH control. The reaction occurred at 100 °C at different test times. Analyzes of infrared spectroscopy showed functional groups characteristic of hydroxyapatite after 36 h of reaction; in addition, the biomaterial was identified as the major phase in X-ray diffraction patterns. Scanning electron microscopy of the materials before and after conversion showed a clear change in their morphologies, indicating the success of the synthesis.

Hydrogen Pressure and Temperature Dependence of the Disproportionated State and Magnetic Anisotropy in the ${d}$ -HDDR Process of Nd–Fe–B–Ga–Nb Powders

Nd–Fe–B-based alloy powders were subjected to the dynamic hydrogen disproportionation desorption recombination treatment and the effect of the hydrogen pressure and temperature conditions in the disproportination step on magnetic anisotropy as well as the state of disproportionated samples was investigated. Magnetic anisotropy was maximized when the sample was hydrogen disproportionated at 30 kPa and 800 °C–820 °C. The analyses of the X-ray diffraction (XRD) patterns showed that the iron boride phase formed during the hydrogen disproportionation step crystallized in the tetragonal structure. The lattice parameters and the peak intensity of this iron boride phase in XRD patterns varied depending on the disproportionation conditions. Both magnetic anisotropy and iron boride peak intensity became stronger when the disproportionation condition was close to the boundary of disproportionation and recombination reactions. These results suggest that there is some kind of relationship between magnetic anisotropy and the state of iron boride phase in disproportionated samples.

Phase diagram calculation and predication of Au–Pd–Zr ternary system

Au–Pd–Zr ternary alloy phase diagram at 25 °C was calculated by Panda phase calculation software, and the thermodynamic data were based on three binary alloy phase diagrams: Pd–Au, Au–Zr, and Pd–Zr. Five composition points in the ternary phase diagram were selected to predict the precipitation order. One (32Au–32Pd–36Zr) of the five composition points in ternary phase diagram was chosen to verify the correctness of the phase diagram calculation and the precipitation order by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The unknown phase in XRD patterns was predicated by EDS and materials studio (MS) software. The experimental results show that there are seven key ternary reactions points and 17 phase regions in all isothermal sections at 25 °C. The thermodynamic process and microstructure for the alloy phase can be described in order according to the vertical section in phase diagram. The phase compositions of the chosen one point are consistent with calculation prediction. The unknown phase in XRD patterns should be Zr2AuPd by the first principle X-ray simulation.

Investigation of Cerium-Substituted Europium Iron Garnets Deposited by Biased Target Ion Beam Deposition

We report on the deposition, crystallization, and magnetic properties of cerium-substituted europium iron garnet having the general form of (CeEu)3(FeGa)5O12. The films were deposited on gallium gadolinium garnet and fused quartz substrates using biased target ion beam deposition at a rate of 2.7 nm/min. The Ce:EIG thin film has a composition of Ce1.3Eu1.7Fe3Ga1.6O12, with 30% of the Ce in the 4+ oxidation state and the remainder as Ce 3+ . The film exhibits the primary peaks of the garnet phase in X-ray diffraction patterns. In the visible part of the electromagnetic spectrum, the film on GGG exhibits a Faraday rotation of 3.3°/µm with coercivity of 0.58 kOe, whereas the film on fused quartz exhibits 1.1°/µm with a coercivity of 0.8 kOe. The film on the fused quartz substrate has a saturation magnetization of 17 emu/cm 3 at room temperature.

SOLID STATE REDUCTION OF MoO3 WITH CARBON VIA MECHANICAL ALLOYING TO SYNTHESIZE NANO-CRYSTALINE MoO2

In this research, effect of milling time on solid state reduction of MoO 3 with carbon has been investigated. It was found that mechanical activation of a mixture of MoO 3 and carbon at ambient temperature by high energy ball milling was not able to reduce MoO 3 to metallic molybdenum. MoO 3 was converted to MoO 2 at the first stage of reduction and peaks of the latter phase in X-ray diffraction patterns were detected when the milling time exceeded from 50 hours. The main effect of increased milling time at this stage was decreasing of MoO 3 peak intensities and significant peak broadening due to decrease in size of crystallites. After prolonged milling, MoO 3 was fully reduced to nano-crystalline MoO 2 and its mean crystallite size was calculated using Williamson–Hall technique and found to be 17.5 nm. Thermodynamic investigations also confirm the possibility of reduction of MoO 3 to MoO 2 during the milling operation at room temperature. But, further reduction to metallic molybdenum requires thermal activation at higher temperature near 1100 K. XRD and SEM techniques were employed to evaluate the powder particles characteristics.

Synthesis and characterization of alkylammonium/Bi2212 nanohybrids

Single-phase nanohybrids of Bi2Sr2CaCuO8+d (Bi2212) with alkylammonium salts have been synthesized for the first time by a stepwise intercalation method. To increase the gallery height between the Bi-0 layers of Bi2212 crystal, intercalated precursor was prepared by the chemical vapor transport technique with Bi2212 and HgBr2 in a sealed quartz ampoule. Then, n-dodecyl trimetylammonium bromide (DTA:Br) or n-hexadecyl trimethylammonium bromide (HTA:Br) was intercalated into HgBr2/Bi2212 via ion exchange method. Nanohybrids were characterized by powder X-ray diffraction (XRD). There was no trace of the pristine phase in XRD patterns for all nanohybrids, indicating that DTA or HTA ion is incorporated homogeneously into each Bi2212 layer It is found that the gallery height of Bi2212 host is expanded from 3.08 run to 8.22 run (Δc = 5.14 nm) in HTA/Bi2212 nanohybrid. HTA/Bi2212 nanohybrid was exfoliated into single layers in acetone. A transparent colloid is found to be stable for 5 days after ultrasonication.

Microwave-hydrothermal versus conventional hydrothermal preparation of Ni- and Zn-ferrite powders

Ni- and Zn-ferrite powders were prepared by a coprecipitation method in a microwave-hydrothermal (M-H) reaction. The formation conditions of the ferrite were determined in detail according to the reaction conditions (pH, temperature, and time) in this work. The phase identification, crystallinity, and morphology of the prepared samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The ferrite phase began to form at a relatively low temperature (120°C) in a short-holding time (30 min) under the M-H process. The crystallization of single-phase ferrite was promoted with an increase of annealing temperature and time. In this work, we also compared the ferrite powder prepared by the M-H method with one prepared by the conventional hydrothermal method. Under the same conditions, the sample prepared by the conventional hydrothermal method did not show the ferrite phase in XRD pattern.

Identification of t' Phase in ZrO2‐7.5 wt% Y2O3 Thermal‐Barrier Coatings

The presence of nontransformable tetragonal (t') phase in plasma‐sprayed ZrO2‐Y2O3 coatings enhances the stability of the coating during high‐temperature exposure. In this paper, we describe the importance and procedure for correctly identifying t’phase in X‐ray diffraction patterns of the as‐sprayed and heat‐treated coatings. The results agree with the phase diagram. We also point out that in the heat‐treated materials, the durability should be specified in terms of t'‐ZrO2.