Reference Intensity Ratio Research Articles

Rice Husk as Raw Material in Synthesis of NaA (LTA) Zeolite.

The present work deals with the hydrothermal synthesis of a Na-A (LTA) zeolite using rice husk as a starting material. The focus was on defining the most favorable conditions for the synthesis of zeolite Na-A from rice husk in order to economize on both energy (i.e., synthesis temperatures) and reaction time and to enlarge the field of the pure and isolated synthesized phase. Four sets of experiments were carried out at environmental pressure temperatures varying from 40 °C to 85 °C with a SiO2/Al2O3 ratio from 1.75 to 3.5. Optimal conditions for crystallization of the Na-A zeolite from rice husk were reached at 60 °C with a SiO2/Al2O3 ratio of 1.75. Sixty degrees Celsius represents the minimum known temperature used for the synthesis of NaA zeolite from rice husk. The products of synthesis were characterized by X-ray diffraction, scanning electron microscopy, infrared and Raman spectroscopy. The purity of the synthesized zeolite is verified here for the first time through quantitative phase analysis using the combined Rietveld and reference intensity ratio methods.

Mechanochemical Synthesis of Sodium-Ion Conducting Chloride NaTaCl6

All-solid-state sodium batteries have been attracting attentions owing to their high energy density and safety. Solid electrolytes play a significant role in the electrochemical performances of all-solid-state batteries. Chloride-based solid electrolytes are particularly important for achieving high energy densities because of their high oxidation stability, ionic conductivity, and formability. Fewer sodium-ion conducting chlorides have been developed compared to lithium-ion conducting materials. It is necessary to discover the chlorides as the end-member of sodium-ion conductors. In this study, we report the development of a new NaTaCl6 chloride as an end-member sodium-ion conductor with high ionic conductivity. NaTaCl6 sample was mechanically prepared using a planetary ball mill apparatus. The X-ray diffraction patterns of the obtained sample displayed a broad pattern similar to the reported NaTaCl6 (ICSD#36519), suggesting that the sample contains both amorphous and crystalline phases. The reference intensity ratio method was used to investigate the weight ratios of the amorphous phases in the sample. The ratio was approximately 45 %. Transmission electron microscopy observations suggested that the sample consisted of the amorphous matrix and crystalline with the crystallite size of approximately 20 nm. The electrical conductivities of the pelletized samples were measured using two-terminal AC electrochemical impedance spectroscopy. The sample pellets were prepared by uniaxial pressing at 360 MPa without heat treatment. The pellet sample had the relative density of 85 % (powder density: 3.32 g cm–3, pellet density: 2.83 g cm–3). The sample shows σ 25ºC of 6.2×10–5 S cm–1, and the activation energy of 0.37 eV. To determine the NaTaCl6 onset oxidation voltage (OOV), linear sweep voltammetry measurement was carried out. The OOV of the sample at 60 ºC was 3.8 V vs. Na15Sn4. To demonstrate the high oxidation stability of NaTaCl6 in all-solid-state sodium batteries, it was used in a positive electrode by mixing Na3V2(PO4)3 as the active material and the buffer layer. The cell exhibited an initial reversible capacity of 96 mAh g–1 and stable cycling after 40 cycles with the capacity retention of 99.5 %. A 3.3 V all-solid-state sodium battery without oxide solid electrolytes was successfully operated. In this study, the NaTaCl6 electrolyte was developed with a high ionic conductivity and oxidation stability.Acknowledgement: This work was partly supported by JSPS KAKENHI (Grant Numbers: JP21H04701 and JP19H05816) and MEXT Program: Data Creation and Utilization-Type Material Research and Development Project Grant Number JPMXP1122712807.

Experimental determination of reference intensity ratio essential for accurate thickness measurement of HfO2 ultrathin films by XPS

When measuring the thickness of ultrathin overlayer films using X‐ray photoelectron spectroscopy (XPS), accurate values of the reference intensity ratio (R0) and the effective attenuation length (L) are essential. By definition, R0 is the peak intensity ratio for an overlayer and the substrate in “bulk” phases. Two issues need to be addressed in experimental determining R0 for ultrathin films: (i) How might a contamination layer on the sample used for measuring peak intensities impact R0? And (ii) do differences in the structure or chemistry of an ultrathin film make it inappropriate to determine R0 using bulk forms of the overlayer? In this study, we demonstrate the experimental determination of the R0 for an ultrathin HfO2 film on a Si(100) substrate with a 2 nm SiO2 layer. The values of R0 were determined using (i) the bulk materials of the HfO2 film and substrate and (ii) the ultrathin HfO2 films after different cleaning treatments. The results show that the R0 determined by the ultrathin films is higher than that determined by the bulk materials. Also, keeping the same level of carbonaceous contamination on the sample surface by cleaning as much as possible is essential for an accurate experimental determination of R0. In addition, the effective attenuation length was obtained using samples with known thicknesses measured by X‐ray reflectometry. The thicknesses and uncertainty budget of the ultrathin HfO2 films were then evaluated.

Fe doped LiNi0.8Co0.15Al0.05 O2 (NCA) cathode materials: Synthesis, structural and morphological studies

As a result of its substantial energy density, layered LiNi0.8Co0.15Al0.05O2 cathode materials are thought to be the most promising of the next-generation cathode materials for electric vehicles (EVs). In this research, self propagating combustion (SPC) is used to prepare cathode materials made of pristine LiNi0.8Co0.15Al0.05O2 (NCA) and NCA doped with 1% Fe to produce LiNi0.8Co0.14Fe0.01Al0.05O2. Based on X-Ray Diffraction (XRD) results, pristine and doped NCA cathode materials were pure and single phase. Reference Intensity Ratio (RIR) values for pristine and doped NCA are 0.87 and 1.12 respectively indicating that the amount of cation mixing was reduced with Fe doping. Through Rietveld refinement, it was discovered that the addition of Fe to NCA resulted in a decrease in cation mixing from 13.56% to 4.07%.It was found that both pristine and doped NCA possessed polyhedral like shape morphology. It can be seen that doping with 1% Fe does not change much in the crystallite size of the materials. By having less cation mixing, Fe doped was found to greatly improve the structural integrity of NCA cathode materials, which in turn improved the materials’ electrochemical performance.

Enhancing the Microhardness of Coatings Produced by Cold Gas Dynamic Spraying through Multi-Reinforcement with Aluminum Powders Containing Fullerenes and Aluminum Nitride

Coatings with high hardness were successfully obtained using low-pressure cold spray (LPCS) technology from nanocrystalline powders based on the aluminum alloy AlMg6, which were multi-reinforced with 0.3 wt.% fullerenes and 10–50 wt.% AlN. The powders were synthesized through a two-stage high-energy ball milling process, resulting in a complex mechanical mixture consisting of agglomerates and micro-sized ceramic particles of AlN. The agglomerates comprise particles of the nanocomposite material AlMg6/C60 with embedded and surface-located, micro-sized ceramic particles of AlN. Scanning electron microscopy and EDS analyses demonstrated a uniform distribution of reinforcing particles throughout the coating volume. An X-ray diffraction (XRD) analysis of the coatings revealed a change in the predominant orientation of matrix alloy grains to a more chaotic state during deformation over the course of cold gas dynamic spraying. A quantitative determination of AlN content in the coating was achieved through the processing of XRD data using the reference intensity ratio (RIR) method. It was found that the proportion of transferred ceramic particles from the multi-reinforced powder to the coating did not exceed ~65%. Experimental evidence indicated that LPCS processing of mono-reinforced nanocrystalline powder composite AlMg6/C60 practically did not lead to the formation of a coating on the substrate and was limited to a monolayer with a thickness of ~10 µm. The microhardness of the monolayer coating obtained from the deposition of AlMg6/C60 powder was 181 ± 12 HV. Additionally, the introduction of 10 to 50 wt.% AlN into the powder mixture contributed to the enhancement of growth efficiency and an increase in coating microhardness by ~1.4–1.7 times. The obtained results demonstrate that the utilization of agglomerated multi-reinforced powders for cold gas dynamic spraying can be an effective strategy for producing coatings and bulk materials based on aluminum and its alloys with high microhardness.

Luminescence and photocatalytic properties of bifunctional materials CaTi2O4(OH)2:Eu3+ and [CaTi2O4(OH)2–CaTiO3]:Eu3+

CaTi2O4(OH)2:Eu3+, CaTiO3:Eu3+ and [CaTi2O4(OH)2–CaTiO3]:Eu3+ were synthesized by a solvothermal method without the help of templates or surfactants. And their structures, luminescence properties, and photocatalytic properties were systematically studied. The RIR (reference intensity ratio) data of CaTi2O4(OH)2 were first investigated via X-ray diffraction (XRD), thus the ratios of each phase in the (m%CaTi2O4(OH)2-n%CaTiO3):3%Eu3+ biphasic mixture was determined. The bandgap value of CaTi2O4(OH)2:3%Eu3+ is 0.28 eV less than that of CaTiO3:3%Eu3+. The specific surface area of CaTi2O4(OH)2 is 8.2 times larger than that of CaTiO3. Compared with CaTiO3:Eu3+, the CaTi2O4(OH)2:Eu3+ showed stronger luminescence intensity. The Judd-Ofelt theory analysis show that the Eu3+ ions in CaTi2O4(OH)2:Eu3+ have low local symmetry, high Eu–O bonds covalence and low ligands electron density. The photocatalytic properties of CaTi2O4(OH)2:y%Eu3+, CaTiO3:x%Eu3+ and [62.2%CaTi2O4(OH)2-37.8%CaTiO3]:3% Eu3+ were comparatively studied in detail. The band-gap value of [62.2 % CaTi2O4(OH)2–37.8%CaTiO3]:3%Eu3+ is significantly reduced due to the presence of heterojunctions compared to CaTi2O4(OH)2:y%Eu3+ and CaTiO3: x%Eu3+. The built-in electric potential at heterojunction interface will guide electrons and holes to move in opposite directions, therefore [CaTi2O4(OH)2–CaTiO3]:Eu3+ has excellent photocatalytic activity.

Calculating the reference intensity ratio of crystalline phases with unknown atomic arrangements using the lattice parameters and chemical information

The reference intensity ratio (RIR) is the intensity ratio of a specified peak of the target crystalline phase to a certain peak of the reference phase in the powder X-ray diffraction pattern of a mixture of the target and reference phases in a weight ratio of 1:1. The RIR represents the diffraction power of the target phase compared with that of the reference phase. A quantitative phase analysis (QPA) can be readily made on the basis of only a powder pattern when the RIR values of all component phases in the mixture are available. The RIR of a target phase can be measured experimentally or calculated in accordance with its crystal structure. RIR values are given in most powder diffraction files (PDFs) published by the International Centre for Diffraction Data, but there are still more than 110 000 PDFs for which the RIR is absent. Newly discovered phases may be present in a mixture as components of unknown weight fractions, for which the RIR values can be neither measured nor calculated with the currently available method. Herein is presented a new method of calculating the RIR of a crystalline phase from its lattice parameters, the chemical content of the unit cell and a list of normalized intensities of reflections over a sufficiently large diffraction angle range. The new method can be used to calculate not only the absent RIRs in the PDFs but also the RIR of a component phase of a mixture of unknown weight fraction when the lattice parameters and chemical content of the unit cell of the corresponding phase are known.

Experimental synthesis and crystal structure refinement of a new ternary intermetallic compound Al3GaCu9

A new ternary intermetallic compound Al3GaCu9 was synthesized experimentally. A high-quality powder diffraction pattern of the compound was collected by an X-ray diffractometer, and its crystal structure was determined using the Rietveld refinement method. Results show that the compound has a cubic cell with the Al4Cu9 structure type (space group $P\bar{4}3m$ and Pearson symbol cP52). The lattice parameter a = 8.7132(3) Å, unit-cell volume V = 661.52 Å3, calculated density Dcalc = 7.26 g/cm3, and Z = 4. The residual factors converge to Rp = 2.96%, Rwp = 4.06%, and Rexp = 2.57%. The experimentally obtained reference intensity ratio value is 7.04.

Comparison of Quantitative X-ray Diffraction Mineral Analysis Methods

X-ray diffraction (XRD) analysis, as one of the most powerful methods, has been widely used to identify and quantify minerals in earth science. How to improve the precision of mineral quantitative analysis is still a hot topic. To date, several quantitative methods have been proposed for different purposes and accompanied by diverse software. In this study, three quantitative mineral analysis methods, including the reference intensity ratio (RIR), Rietveld, and full pattern summation (FPS) methods, are compared and evaluated to systematically investigate their accuracy and applicability. The results show that the analytical accuracy of these methods is basically consistent for mixtures free from clay minerals. However, there are significant differences in accuracy for clay-mineral-containing samples. In comparison, it seems that the FPS method has wide applicability, which is more appropriate for sediments. The Rietveld method has been shown to be capable of quantifying complicated non-clay samples with a high analytical accuracy; nevertheless, most conventional Rietveld software fails to accurately quantify phases with a disordered or unknown structure. The RIR method represents a handy approach but with lower analytical accuracy. Overall, the present results are expected to provide a potentially important reference for the quantitative analysis of minerals in sediments.

LiNi0.3Mn0.3Co0.3O2 (NMC 111) cathode material synthesize via combustion Method: Effect of combustion fuel on Structure, morphology and their electrochemical performances

Using different fuels during the synthesis process will affect the cathode materials' phase, morphology, crystallinity, and electrochemical performance. In this work, the synthesis of LiNi1/3Mn1/3Co1/3O2 (NMC111) was done using the combustion method. Different fuels which are citric acid, urea, and glycine were used to study the effect on the phase, morphology, and performance of the materials. The final products of NMC 111 synthesized using citric acid, glycine and urea were denoted as LC, LG, and LU, respectively anneal at 800 ˚C for 24 h. Based on the XRD results, all materials showed a pure, single phase and isostructural with hexagonal α-NaFeO2. LC material shows good cation ordering with a higher Reference Intensity Ratio (RIR) value of 1.25. Meanwhile, FESEM results revealed that all materials have a morphology of polyhedral-like shape and well-crystallized particles with smooth surfaces. LC material displays a smaller crystallite size compared to the LG and LU materials. From the XRD and FESEM results, LC material has the potential as cathode material that has good cation ordering and a smaller crystallite size that provided a larger surface area which can promote more Li+ ions diffusion resulting in an excellent electrochemical behavior. This proves when LC show the highest initial discharge capacity of 130.80 mAhg−1 compared with LG and LU materials and can retain their discharge capacity up to 117.51 mAhg−1 after the 30th cycle. The findings from this work prove that higher enthalpy combustion (ΔcH°solid) of citric acid can govern a good crystal structure growth of the NMC111 material that has a good cation ordering with low cation mixing, higher crystallinity, and smaller crystallite size and subsequently leads to a good electrochemical performance.

Valorisation of Water Potabilization Sludges as Precursors for Alkali-Activated Binders: Characterization and Feasibility Study.

Water potabilization sludges (WPS) are a heterogeneous waste generated from the coagulation-flocculation process of drinking water production, whose composition is highly dependent on the geological context of reservoirs, the composition and volume of treated water, and the types of coagulants used. For this reason, any feasible approach for reusing and valorising of such waste cannot be disregarded from the detailed investigation of its chemical and physical characteristics and they have to be evaluated at a local scale. In this study, WPS samples from two plants serving the Apulian territory (Southern Italy) were subjected for the first time to a detailed characterization with a view to evaluating their recovery and reuse at a local scale as a raw material for producing alkali activated binders. WPS samples were investigated by X-ray fluorescence (XRF), X-ray powder diffraction (XRPD) including phase quantification by the combined Rietveld and reference intensity ratio (RIR) methods, thermogravimetric and differential thermal analysis (TG-DTA), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Samples showed aluminium-silicate compositions with up to 37 wt% of Al2O3 and up to 28 wt% of SiO2. Small amounts of CaO were also found (6.8 and 4 wt%, respectively). The mineralogical investigation indicates the presence of illite and kaolinite as clayey crystalline phases (up to 18 wt% and 4 wt%, respectively), in addition to quartz (up to 4 wt%) and calcite (up to 6wt%) and a large amorphous fraction (63 wt% and 76 wt%, respectively). WPS were subjected to heating from 400 °C to 900 °C and mechanical treatment by high energy vibro-milling in order to determine the best pre-treatment condition in view of their use as solid precursors to prepare alkali-activated binders. Alkali activation (8M NaOH solution; room temperature curing) was attempted on untreated WPS, on 700 °C heated and on 10-minute high-energy milled samples, which were considered the most suitable based on the preliminary characterization. Investigations of alkali-activated binders confirmed the geopolymerisation reaction occurrence. Variations in gel features and compositions depended on the amount of reactive SiO2, Al2O3 and CaO available in the precursors. WPS heated at 700 °C led to the most dense and homogeneous microstructures, due to a greater availability of reactive phases. The results of this preliminary study demonstrate the technical feasibility of preparing alternative binders from the investigated Apulian WPS, paving the way for a local reuse of these waste products, leading to economic and environmental benefits.

Synthesis of copper nano/microparticles via thermal decomposition and their conversion to copper oxide film.

Copper nano/microparticles were synthesized in octadecene at 290 °C by thermal decomposition method. Copper acetate monohydrate, stearic acid, and 1-octadecanol were used as copper precursor, capping and mild reducing agents, respectively, at the synthesis. Borosilicate glass substrates submerged into the reaction solution during the synthesis were coated by copper nano/microparticles. Thermal decomposition and coating techniques were combined in this study. Copper nano/microparticles were thoroughly characterised via X-ray powder diffraction, X-ray photoelectron, Raman, and attenuated total reflectance-Fourier transform infrared spectroscopies, and scanning and transmission electron microscopies. The average minimum Feret's diameter of these synthesized copper particles was measured as ~87 ± 19 nm. Copper nano/microparticles were converted to copper oxide nano/microparticles by applying heat treatment at 250 °C. The phase composition of copper oxide nano/microparticles was determined by reference intensity ratio analysis. The energy gap of copper oxide nano/microparticles was determined as ~2.33 eV by using Tauc's method. Their band gap PL emission was observed at ~2.15 eV.

Quantitative Deviation of Nanocrystals Using the RIR Method in X-ray Diffraction (XRD).

The reference intensity ratio (RIR) method, using X-ray diffraction (XRD), is considered one most of the rapid and convenient approaches for phase quantification in multi-phase mixture, in which nanocrystals are commonly contained in a mixture and cause a broadening of the diffraction peak, while another broadening factor, instrumental broadening, does not attract enough attention in related quantitative analysis. Despite the specimen consisting of 50 wt.% TiO2 nanomaterials (nano-TiO2) and 50 wt.% microscale ZnO powder, the nano-TiO2 quantitative result changes from 56.53% to 43.33% that occur as a variation of instrumental broadening are caused by divergence slit adjustment. This deviation could be accounted through a mathematical model that involves instrumental broadening. The research in this paper might provide a useful guide for developing an approach to measure accuracy quantification in unknown multi-phase mixtures

Influence of the ratio of the intensities of the reference and object waves on the intensity distribution in the holographic field

The results of the research focused on the reference and object beam intensity ratio effect on the transmittance of computer-generated and analog holograms are presented. Particular attention is paid to the hologram synthesis mode in which the intensity of the object beam exceeds the intensity of the reference beam (overmodulation mode). The study is relevant in cases where computer-generated holograms are used in extreme ultraviolet projection photolithography. Mathematical modeling of the physical processes of recording and reconstructing holograms has been performed. The characteristic size of the binary test object was 80 × 80 nm, the radiation wavelength was 13.5 nm, the hologram pixel size was 20 × 20 nm, the distance between the object and hologram planes was 20.4 μm, and the incidence angle of the plane reference wave was 14°42′. Synthesis and reconstruction of holograms were carried out in an overmodulation mode, with different beam paths in the object beam. It is shown that the computer-generated holograms, unless binarized, are always displayed and reconstructed as quantized holograms with a quantization interval depending on the parameters of the synthesis scheme. It has been established that the influence of the overmodulation mode on the quality of the reconstructed image when using computer-generated holograms will be much less than in the case of using analog holograms, but will also be determined by the dynamic range of the object beam intensity in the hologram synthesis plane. It is noted that the influence of overmodulation mode is minimal if an object beam converging at the center of the hologram is used during synthesis. The choice of the adequate quantization interval and the ratio of the intensities of the reference and object beams will ensure high quality of the reconstructed image when using computer-generated Fresnel holograms in extreme ultraviolet projection photolithography.

Evaluation of the Structural Deviation of Cu/Cu2O Nanocomposite Using the X-ray Diffraction Analysis Methods

We successfully synthesized Cu/Cu2O nanocomposites using the wet chemical synthesis method. All X-ray diffraction (XRD), Reference Intensity Ratio (RIR), and Rietveld refinement methods confirmed that the compounds Cu and Cu2O are free of impurities. Scanning Electron Microscope (SEM) and Transmission electron microscopy (TEM) images show the morphology and interactions of Cu and Cu2O in the structure. The formation mechanism is also explained by five stages: precursor, nucleation, growth, aging, and reduction. The changes in crystallization parameters under variations in reaction temperature (Tv) and stirring speed (Sv) were confirmed by agreement with the XRD database. The lattice constant in the crystal of nanocomposite increases with rising temperature in the reaction, leading to unit cell expansion, while increasing the stirring—rate leads to a random size distribution of the lattice parameter. Due to the imperfect growth of the crystal, the induced crystallite size was calculated using the Williamson-Hall model, and the precise lattice parameter values were calculated using the Nelson-Riley function.

Controllable synthesis of bifunctional material Ca2Ti2O6:Eu3+ and its comparative study on luminescence and photocatalytic properties with CaTiO3:Eu3+

Pure pyrochlore Ca2Ti2O6, perovskite CaTiO3, and their mixed crystalline phases with different proportions were controllably synthesized via a solvothermal method, followed by a subsequent calcination process. RIR (reference intensity ratio) data of Ca2Ti2O6 were first obtained by X-ray diffraction (XRD), which can be used to quantitatively analyze the phase composition. When Eu3+ is doped into these calcium titanium oxides, they can be used as luminescent and photocatalytic materials. The structure, luminescence, and photocatalytic properties of pure pyrochlore Ca2Ti2O6:Eu3+ and perovskite CaTiO3:Eu3+ were comparatively studied in detail. The relative intensities of the excitation peaks and the emission peaks in Ca2Ti2O6:Eu3+ and CaTiO3:Eu3+ are different, which is attributed to the different symmetries of Eu3+ inhabiting the two kinds of lattices. In addition, although the luminescence intensity of CaTiO3:3%Eu3+ is higher than that of Ca2Ti2O6:3%Eu3+ under excitation at 394 nm, the luminescence intensity of Ca2Ti2O6:3%Eu3+ is superior to that of CaTiO3:3%Eu3+ under excitation at 464 nm and 533 nm. Photocatalytic experiments show that Ca2Ti2O6:3%Eu3+ has better photocatalytic performance than CaTiO3:3%Eu3+, which is mainly due to its smaller crystallite size, higher specific surface area and pyrochlore structure. In addition, biphase (Ca2Ti2O6–CaTiO3):3%Eu3+ has the best photocatalytic activity compared with the single phase Ca2Ti2O6:3%Eu3+ and CaTiO3:3%Eu3+, owing to the presence of heterojunctions that significantly reduced the band gap. It is anticipated that the discovery of this bifunctional Ca2Ti2O6:Eu3+ would expand the application of rare earth-doped calcium titanium oxide materials.

Crystal structure and magnetic properties of ternary Al3CoNd2 compound

A ternary compound Al3CoNd2 was synthesized and its crystal structure parameters were determined by the Rietveld refinement method based on powder X-ray diffraction data. Results show that the compound crystallizes in the MgCu2-type structure (cubic Laves C15 phase, space group $Fd\bar{3}m$), with the lattice parameter of a = 7.8424(2) Ǻ, unit-cell volume of V = 482.33 Å3, and calculated density of Dcalc = 5.90 g.cm−3. The residual factors converge to Rp = 0.1024 and Rwp = 0.1287. The reference intensity ratio value obtained experimentally is 3.03. Magnetic susceptibility measurements indicate an agreement with the Curie–Weiss law in the temperature range of 385–450 K, and paramagnetic Curie temperature of θp = 379.9 K. Both rare-earth elements and cobalt ions contribute to the paramagnetic moment. The saturation magnetic moment and magnetic hysteresis loop were measured for the Al3CoNd2 compound at various temperatures. Results show that the saturation magnetic moment value decreases with an increase in temperature and the compound becomes a ferromagnet below the Curie temperature Tc.

Synthesis and characterization of analcime (ANA) zeolite using a kaolinitic rock

Analcime is nowadays an important component in dental porcelain systems, in heterogeneous catalysis, in the nanoelectronic field, in selective adsorption and in stomatology (dental filling and prosthesis). Analcime synthesis from an impure, silica-rich kaolinite rock coming from Romana (Sassari, Italy) is here presented. A synthesis protocol is proposed that aims to make an improvement of synthesis conditions compared to the past. The hydrothermal treatment is in fact here achieved without aging times and without the use of sodium silicate or other additional silica source reported in the literature. Lower calcination temperature, synthesis temperature and crystallization time are verified in this work. The kaolin is subjected to calcination at the temperature of 650 °C and then mixed with NaOH. The experiment is performed at ambient pressure and 170 ± 0.1 °C. The degree of purity of analcime is calculated in 97.57% at 10 h. Analcime is characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, inductively coupled plasma optical emission spectrometry and thermal analysis. Density is also calculated. Cell parameters and the amount of amorphous phase in the synthesis powders is estimated with quantitative phase analysis using the combined Rietveld and reference intensity ratio methods. The experimental conditions make the synthesis protocol particularly attractive from an economic point of view. Also this work does not use a commercial kaolin but silica-rich impure kaolinitic rock from a disused quarry. This further reduces the costs of the experimental protocol. It also gives the protocol an added value, as the synthesis of a useful mineral is obtained through the valorization of an otherwise unused georesource. Both chemical and physical characterization of analcime is satisfactory making the experimental protocol very promising for an industrial transfer.

Thickness determination of the gilding on brass materials by XRF technique

The gold coating layer of the gold-plated brass objects was estimated using calibration curves obtained with a handheld X-ray fluorescence spectrometer (XRF). Calibration curves were obtained using reference materials (Au and brass) and intensity ratios of the X-ray fluorescence peaks generated in both the gold coating and the brass substrate. In addition, a calibration was also performed with the PLS (Partial Least Squares) multivariate analysis method. Good agreement was obtained by comparing the results of the different methods. The calibrations were successfully applied to gold-plated brass jewels and samples.

Synthesis and characterization of Na-P1 (GIS) zeolite using a kaolinitic rock

This work focuses on the hydrothermal synthesis of Na-P1 zeolite by using a kaolinite rock coming from Romana (Sassari, Italy). The kaolin is calcined at a temperature of 650 °C and then mixed with calculated quantities of NaOH. The synthesis runs are carried out at ambient pressure and at variable temperatures of 65 and 100 °C. For the first time compared to the past, the Na-P1 zeolite is synthesized without the use of additives and through a protocol that reduces both temperatures and synthesis times. The synthesis products are analysed by X-ray diffraction, high temperature X-ray diffraction, infrared spectroscopy, scanning electron microscopy and inductively coupled plasma optical emission spectrometry. The cell parameters are calculated using the Rietveld method. Density and specific surface area are also calculated. The absence of amorphous phases and impurities in synthetic powders is verified through quantitative phase analysis using the combined Rietveld and reference intensity ratio methods. The results make the experimental protocol very promising for an industrial transfer.