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There is a strong inducement to develop new inorganic materials to substitute the current industrial pigments, which are known for their poor ultraviolet absorbent and low photoluminescence (PL) properties. The purpose of this paper is to invent a better rare-earth-based pigment material as a spectral modifier with good luminescence properties to enhance the spectral response for photovoltaic panel application.

Different phosphor samples made of nano-calcium carbonate (CaCO₃) with varied wt.% of the dopant Dysprosium doped calcium borophosphate (CBP/Dy) as (W0 – 0%, W1 – 3,85%, W2 – 7.41%, W3 –10.71% and W4 –13.79%) were prepared via the solid-state diffusion method at 600 °C for 6 h using a muffle furnace. The structural, morphological and luminescence properties of the CaCO₃:CBP/Dy powder samples were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and PL test.

The XRD, SEM and FTIR results verified the crystalline formation, morphological behaviour and vibration bonds of synthesized CBP/Dy-doped CaCO₃ powder samples. XRD pattern revealed that the synthesized powder samples exhibit crystalline structured materials, and SEM results showed irregular shape and porous-like structured morphologies. FTIR spectrum shows prominent bands at 712, 874 and 1,404 cm⁻¹, corresponding to asymmetric stretching vibrations of CO3²⁻ groups and out-of-plane bending. PL characterization of CBP/Dy-doped CaCO₃ (sample W) shows emission at 427 nm (λmax) under the excitation of 358 nm. The intensity of PL emission spectra drops due to the concentration quenching effect, while the maximum PL intensity is observed in the W3 phosphor powder system.

This phosphor powder is expected to find out the potential application such as a spectral modifier which is applied to match the energy of photons with solar cell bandgap to improve spectral absorption and lead to better efficiency.

The introduction of a nano-CaCO₃:CBP/Dy hybrid powder system with good luminescence properties to be used as spectral modifiers for solar cell application has been synthesized in the lab, which is a novel attempt.

To evaluate the effect of flux, activator and co‐activator on solid state synthesis of SrAl₂O₄: Eu^2 +, Dy^3 + phosphor, where boric oxide, europium oxide and dispersium oxide were used, respectively.

To optimise synthesis condition of long lasting phosphorescence SrAl₂O₄ phosphor, boric oxide was used as a flux. To improve relative intensity of SrAl₂O₄: Eu^2 + phosphor, the critical concentration of Eu^2 + was determined. The effect of various concentration of co‐activator on afterglow properties, the effect of Dy^3 + ion on the emission and excitation spectra were examined.

The SrAl₂O₄: Eu^2 +, Dy^3 + phosphor powders have been synthesised by solid state reaction method. The result of XRD patterns indicated that, addition of 5 mol% B₂O₃ enhanced the formation of SrAl₂O₄ at 1,200°C. Investigation on the variation of emission intensity of different phosphors containing different amounts of Eu^2 + revealed that after 6 mol% of Eu^2 + concentration, quenching process occurred. Dy^3 + formed trap levels and results demonstrated that increasing concentration of Dy^3 + up to 5 mol% reduced the relative intensity and increased the decay time.

Using B₂O₃ as a flux and solid state reaction method for preparation of this phosphor is in good agreement with industrial production and make it economic, because of reduced sintering temperature.

The purpose of this paper is to establish physical-chemical patterns and process parameters for obtaining low-temperature pink pigments with the structure of tin sphene using granulated blast-furnace slag.

Thermodynamic calculations were made in the work to assess the probability of malayaite phase formation during firing of slag-containing pigments. Mineralogical composition of synthesized pigments was evaluated by X-ray phase analysis. Spectral characteristics of pigments absorption in the infrared region were determined with the use of Fourier IR-spectrometry. Colour characteristics of the developed pigments and glass coatings with their introduction were studied on the comparator colour. Density of ceramic pigments was determined by pycnometric method, and chemical resistance was found on their weight loss after boiling in 1 N hydrochloric acid solution and 1 N sodium hydroxide solution.

Peculiar features of formation of the mineralogical composition of pink pigments are studied in the system CaO-MgO-Al₂O₃-SiO₂-SnO₂-Cr₂O₃ with the use of granulated blast-furnace slag. The end product and carrier of the pink colour is the solid solution on the basis of tin sphene. It is established that the most rational concentration of chromium (III) oxide for the formation of pink colouring of the pigments is 2 Wt.%.

The usage of developed pigments provides obtaining high-quality pink-coloured glaze coatings, in particular for ceramic tiles.

Activity of the components of blast-furnace slag in combination with the effective mineralizing action of B₂O₃ additive allows performing the firing of pink of the pigments with the formation of tin sphene at reduced temperature of 1,200°C.

The purpose of this article is to evaluate the role of mineralisers on the formation of perovskite structure, optimise the amounts of chromium content, soaking time and finally the ratio of fuel (citric acid) to oxidiser (metal nitrate) and investigation of the physical properties of resulted pigments.

A red pigment based on perovskite structure (YAl_1-yCr_yO₃, y = (0.01-0.1) was synthesised by solution combustion method with various mineralisers, like NaF, MgF₂ and Li₂CO₃. Thermal decomposition of the resulting nitrate-citrate gels and the phase evolution of calcined powders were investigated and the microstructure and colorimetry of the emerging products were characterised.

The most effective mineraliser system for the formation of YAlO₃ perovskite was NaF:MgF₂:Li₂CO₃ (3:2:1 by weight). Furthermore, desirable pigments were obtained by firing the samples at 1,400°C for 4 hours. The highest redness parameter (a*) and reflectance value were obtained when y was 0.03 and 0.01, respectively. Increasing the fuel: oxidiser ratio led to an increase in the a* parameter. Use of the optimum prepared red pigment in the low and high firing temperature glazes gave a high chemical and thermal stability.

Only citric acid was used as fuel. Other fuels and different ratios of fuel to oxidiser could also be studied.

The method developed provided a new approach for preparation to nontoxic, high-temperature, ceramic red pigment compared to the solid-state method.

The methods for synthesis of pigment based on perovskite structure with different chromium contents and for evaluation of thermal stability of pigment in glaze were novel.

The purpose of this study is to introduce mechanochemically prepared polyaniline anticorrosive additives. In primer coating technology, there is an increasing interest in the development of efficient anticorrosive additives which replace the conventional inorganic anticorrosive pigments like heavy metal chromates and phosphates normally added to primer paints for the coating on metals. Conducting polymers are found to be better alternatives.

Polyaniline phosphate is synthesized through solid-state conditions without using any solvent. The synthesized polyaniline phosphate is added in the primer formulation instead of zinc phosphate. Primers with different quantity of zinc phosphate are also formulated and studied for comparison. The comparison between their abilities to control corrosion of carbon steel were done with application of open-circuit potential monitoring, polarization and electrochemical impedance spectroscopy methods in 3.5 per cent NaCl solution.

Corrosion studies indicate that polyaniline phosphate can improve corrosion protection properties by taking part the passivation processes. The performance of polyaniline phosphate is better than zinc phosphate.

I certify that the results are from our original research and this paper is neither considered for publication elsewhere nor published previously.

The aim of the present work was the characterization of a group of compounds with the perovskite‐type structure in respect of their applicability as thermistor materials.

Four compositions: La_0.7Sr_0.3Zr_0.5Co_0.2²⁺Co_0.3³⁺O₃, La_0.8Sr_0.2Ti_0.5Co_0.3²⁺Co_0.2³⁺O₃, La_0.4Sr_0.6Ti_0.3Fe_0.7O₃ and CaTi_0.8Co_0.2O₃ were synthesized by solid‐state reaction. Ceramic thermistor materials were sintered in the temperature range 1,300‐1,400°C. The synthesized powders were used for fabrication of thick film pastes and thermistors fired at 1,100‐1,250°C. Resistance‐temperature characteristics of the ceramic samples were studied in the range −55 to 800°C for the ceramic samples and 20‐600°C for thick films. Endurance tests at 300°C for 500 h were performed.

The developed NTC materials exhibited high temperature coefficients of resistivity, dense microstructure and good stability. The most advantageous characteristics have been shown by La_0.7Sr_0.3Zr_0.5Co_0.2²⁺Co_0.3³⁺O₃ and La_0.8Sr_0.2Ti_0.5Co_0.3²⁺Co_0.2³⁺O₃ thermistors. The highest Temperature coefficient of resistances for the ceramics were found in the temperature range from −55 to 180°C (−10.7 to −2.9 per cent/°C) and for the thick films in the temperature range 40‐300°C (−5.6 to −1.5 per cent/°C).

This work has been focused on preliminary choice of compositions appropriate for practical thermistor thick film applications. Elucidation of conduction mechanism of the investigated materials needs further complex studies of conductivity, nonstoichiometry, thermoelectric power, etc. as a function of temperature and oxygen partial pressure.

In this work, an attempt has been made to extend the typical range of NTC compositions and to fulfil the demand for improved stability of bulk and thick film thermistors at elevated temperatures.

This paper aims to present the comparative study on the composition, microstructure and dielectric behavior of a group of new nonferroelectric high-permittivity A_2/3CuTa₄O₁₂ (A = Y, Nd, Sm, Gd, Dy or Bi) ceramics.

The materials under investigation were synthesized by solid-state reaction method and sintered at 1,120-1,230°C. Dielectric properties were investigated in the temperature range from −55 to 740°C at frequencies 10 Hz to 2 MHz. Microstructure, elemental composition and phase composition of the ceramics were examined by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) methods. DC conductivity was studied in the temperature range 20-740°C.

XRD analysis revealed peaks corresponding to Cu₂Ta₄O₁₂ along with small amounts of secondary phases based on tantalum oxides. Impedance spectroscopic data and the results of SEM and EDS studies imply the spontaneous formation of internal barrier layer capacitors in the investigated materials. Two steps can be distinguished in the dielectric permittivity versus frequency plots. The low-frequency step of 1,000-100,000 is assigned to grain boundary barrier layer effect, while the high-frequency one of 34-46 is related to intrinsic properties of grains.

Search for new high-permittivity capacitor materials is important for the progress in miniaturization and integration scale of electronic passive components. The paper reports on processing, microstructure, microanalysis studies and dielectric properties of a group of novel nonferroelectric materials with the perovskite structure of CaCu₃Ti₄O₁₂ and the general formula A_2/3CuTa₄O₁₂, being spontaneously formed internal barrier layer capacitors.

Miniature switches with rockers and paddle levers have electrical characteristics similar to the basic range with contact ratings (resistive load) of .2 amp at 250Vac and 5amp at either 125Vac or 28Vdc. Initial contact resistance is 0010 ohms and insulation resistance 1,000 megohms. Contacts and terminals are of solid silver and the minimum mechanical life is 50,000 operations. Each type, both rockers and paddle levers, is available in single or two pole models with a choice of four contact arrangements and four standard colours for the mouldings.

This study aims to investigate the possibility of synthesizing cobalt doped willemite ceramic blue pigment by using Egyptian white sand as environmental and economical raw material for multi-applications in coatings and inks.

After the synthesis process, the prepared blue pigment was characterized via X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis technique. Then the blue pigment was integrated into both coating and ink formulations. The effect of the prepared multifunctional coatings on corrosion resistance and thermal stability was evaluated using different standard tests. Also, the effect of inclusion of blue pigment in flexographic printing ink formulation was done.

The results showed that the coating containing the cobalt doped willemite blue pigment offered good anticorrosive performance and high thermal stability. Additionally, the presented results revealed that integration of the blue pigment in flexographic printing ink formulation enhanced fineness, gloss, viscosity and color more than the commercial one “FX 430–201.”

In conclusion, relied on the eco-friendly principle which can be regarded as an economic and green strategy, it can be obtained that this new pigment can provide good multifunctions such as corrosion resistance and thermal stability in coatings and good fineness, gloss, viscosity and color in inks which can enable them to be widely applied in different industries.

The purpose of this study is to investigate the presence of silicon dioxide (SiO₂) nanoparticles in o-toluidine monomer as a reactant and ammonium persulfate as an oxidant to obtain the poly(o-toluidine) (POT)/SiO₂ nanocomposites by oxidative polymerization method.

Fourier transformation infrared spectroscopy, X-ray diffraction and field emission scanning electron microscopy were used to characterize the structural properties of the composite. POT/SiO₂ nanocomposites were mixed with acrylic resin through a solution mixing method and the composites were coated onto the surface of mild steel. Electrochemical measurements were used to determine the corrosion protection efficiency (P.E.%) of polymer composite coatings using 3.5% NaCl solution as corrosion environment.

The results obtained reveals that the POT/SiO₂/acrylic resin composite coatings have got higher corrosion P.E.% than that of POT/acrylic resin coatings.

The formation of uniformly passive layer in the POT/SiO₂ composite was used to enhance the P.E.% on mild steel surface. The POT/SiO₂/acrylic resin nanocomposites showed effective anticorrosive behavior on mild steel in 3.5% NaCl solution.