Low-temperature Procedure Research Articles

Separation of minor actinides from highly acidic solutions using diglycolamide modified mesoporous silica synthesized via a novel “ring-opening click” reaction

Solid-phase extraction represents a promising approach for partitioning of trivalent minor actinides (MAs) from high-level liquid waste, which is crucial for the decontamination of radioactive waste. However, highly acidic effluents poseaformidablechallengefor extraction materials. Herein, the diglycolamide ligands functionalized mesoporous silica robust matrixs were prepared, resulting in rapid and efficient separation of MAs from strong nitric acid media. This paper reports the first modification of SBA-15-type mesoporous silica through a “ring-opening click” reaction under mild conditions. Five modified silica materials with monolayer diglycolamide ligands containing different terminal groups were obtained using low temperature (0–25 °C) procedures. The rigid and open pore structure of SBA-15 is retained under such mild conditions, allowing facile diffusion and open access to the monolayer ligands. The functionalized product SBA-15-DEDGA exhibited a strong affinity for trivalent MAs in highly acidic solutions and could separate trace amounts of radioactive Am(III) from 1 to 8 M nitric acid solutions with high efficiency (> 98%) within 1 min; the largest distribution coefficient exceeded 5 × 104 mL/g. Solid-state nuclear magnetic resonance spectroscopy combined with X-ray photoelectron spectroscopy of Eu(III) revealed that the binding mechanism involves direct coordination of Eu(III) to a tridentate oxygen-binding site. Additionally, selective separation of americium from curium was achieved with separation factors up to 191 ± 20 through oxidation of Am(III) by sodium persulfate. The superlative and efficient sorption performance of these materials demonstrates their utility in the immobilization of trivalent actinides and the separation of americium from curium.

Direct glass-to-glass bonding obtained via simplified ammonia-based low-temperature procedure resists high shear stress and powerful CW fiber laser irradiation.

Direct glass-to-glass bonding is important for high-technology components in optics, microfluidics, and micro-electromechanical systems applications. We studied direct bonding of 1 mm thick soda-lime float glass substrates. The process is based on the classic RCA-1 cleaning procedure from the semiconductor industry modified with an ammonium hydroxide rinse, followed by a thermal treatment under unidirectional pressure without the need for a dedicated drying step. RCA-1 uses a solution of ammonium hydroxide and hydrogen peroxide to clean contaminants off the surface of silicon and enable subsequent bonding. Bond quality was evaluated using destructive shear testing. Strong bonds (≈7.81 MPa on average) were achieved using unidirectional pressure of approximately 0.88 MPa and bonding temperatures between 160 °C and 300 °C applied for 30 min. Surface roughness and chemistry was characterized before and after cleaning. The optical robustness of the bonds was tested and shown to be capable of surviving high powered continuous wave (CW) fiber laser irradiation of at least 375 W focused for 2 s without delamination. Melting of the substrate was observed at higher powers and longer exposure times.

Novel flexible photochromic device with unprecedented fast-bleaching kinetic via platinum decoration on WO3 layer

Photochromic devices (PC) are considered as ideal candidates for integrated building applications because of their ability to control light and heat transfer into/out of building inner spaces without any external power supply. However, several issues restrict their practical application, including long-term stability concerns due to the volatile nature of the commonly used liquid electrolyte, the high replacement/installation cost associated with their rigid device architecture, and an extremely slow bleaching speed during reversion to their original state due to the lack of an external stimulus such as electricity. The present study aimed to resolve these bottlenecks. Firstly, we exploited a highly stable and conductive polymer-gel electrolyte based on UV-curable trivalent acrylate instead of using organic liquid-based electrolytes. Secondly, we explored a low-temperature UV-curing procedure to deposit the chromogenic WO3 and TiO2 layers, suitable for fabricating a flexible PC device. Finally, a catalytic amount of Pt nanoparticles was successfully incorporated on the surface of the WO3 layer using an identical UV-curing route, which was found to significantly enhances the bleaching speed of the resulting PC device. Thanks to the combined positive effects, the fabricated PC device displayed a deep contrast in coloration (approximately 60 %), unprecedented bleaching kinetic with 90 % recovery of its original transmittance value within 45 min in the dark condition, and prolonged long-term operation for over 1000 coloration-bleaching cycles. These results open way to making efficient PCs for not only smart windows but also for other bendable or wearable applications.

Design of Novel Photocatalytic Films for the Protection of Architectural Surfaces via the Incorporation of Green Photocatalysts

In conservation science the demand of multifunctional green materials displaying water repellency, consolidation, resistance to organic pollutants and pigments is constantly increasing. This research developed a green nanocomposite exhibiting photocatalytic, hydrophobic, consolidation and self-cleaning properties. This was achieved by synthesizing a TiO2 photocatalyst enriched with carbon dots (C-dots) and successfully incorporated into a tetraethoxysilane nanocomposite modified with nano-calcium oxalate and polydimethylsiloxane. The TiO2/C-dots that were prepared with a simple, low temperature, cost-effective and large-scale procedure were assessed via analytical and spectroscopic techniques and were resulted in anatase structure ranging in size from 10 to 40 nm. Photooxidation measurements displayed that TiO2/C-dots nanoparticles could photodegrade completely Methyl Orange (MO) under UV and visible irradiation after 120 min. The photocatalytic performance of the nanocomposite with TiO2/C-dots resulted promising under UV after longer irradiation time. The degradation of MO was faster on bulk xerogels containing the TiO2/C-dots than the corresponding ones with TiO2. The treatment of concrete, limestone and lime mortars with the nanocomposite proved to be compatible with the substrates in terms of aesthetical aspects. This study demonstrates encouraging potential for large-scale production of a multifunctional protective composite that offers hydrophobicity, self-cleaning properties and consolidation to architectural surfaces.

한국형 전투기 온도 환경시험 프로파일 적합화 연구

Purpose: To enhance the temperature environmental stress reliability and export competitiveness for Korean fighter aircraft, the temperature environmental test profiles are optimized for several test conditions, exposure time, and other relevant temperature test procedures.<BR>Methods: The considered severe test conditions and exposure time are based on MIL-HDBK-310: 1997. The high temperature combined test procedure represents a combination of high-temperature procedures and solar radiation procedures; in contrast, the low temperature combined test procedure represents a combination of the low-temperature procedures and icing/freezing rain procedures specified in MIL-STD-810H:2019.<BR>Results: Tailored high/low temperature combined test profiles are established considering a variety of operating temperature environmental conditions experienced during the export lifetime for Korean fighter aircraft.<BR>Conclusion: The tailored temperature test profiles derived considering the appropriate climatic conditions of the respective exporting countries can help enhance the aircraft environmental reliability and reduce the development test cost. Moreover, the profiles can be used to develop similar aircraft.

The influence of low-temperature sterilization procedures on piezoelectric ceramics for biomedical applications

Piezoelectric materials are intensively investigated for usage in biomedical applications ranging from in vivo sensors and energy harvesters to implants for bone and neural cell stimulation. Besides the high requirements for reliability and low cytotoxicity, implantable materials must be sterilizable without losing their functionality. In this study, we investigate the impact of low temperature plasma sterilization and the associated cleaning routines on the piezoelectric properties of PZT, BCZT and KNN bulk ceramics. The stability of the piezoelectric response strongly depends on the material system, with BCZT ceramics showing the strongest decline in properties. Several factors were identified to contribute to this reduction of the piezoelectric coefficient, the most important being mechanical stress due to sample handling as well as chemical reactions during cleaning, disinfection and sterilization. The study highlights the importance of evaluating the impact of all influencing factors along the pre-implantation handling chain in the material selection process.

Room temperature and surfactant free synthesis of zinc peroxide (ZnO2) nanoparticles in methanol with highly efficient antimicrobials

In the present work, a fast, facile, low temperature, and surfactant free synthesis procedure is developed for the preparation of zinc peroxide nanoparticles (ZnO2NPs) in methanol solution. ZnO2 were prepared via reduction of methanolic solution of zinc ions using NaBH4 as a reducing agent to metallic zinc, followed by oxidation using hydrogen peroxide. The produced ZnO2 nanoparticles were characterized using TEM, SEM, TG, DSC, Raman, XRD, FTIR, UV–Vis absorption spectroscopy. The mean size of the nanoparticles was around 15 nm based on SEM and TEM measurements. Interestingly, ZnO2 showed effective antibacterial and antifungal activities. Antibacterial activity was examined versus medically substantial Multidrug Resistant Bacteria (MDR) Gram-positive, Methicillin-Resistant Staphylococcus Aureus (MRSA), and Gram-negative, klebsiella pneumoniae (MDR). Low concentration as 16 mg/L was recorded as minimum inhibitory concentration (MIC) towards the MDR bacterial. Antifungal activity was conducted against Candida albicans (C. albicans), and 16 mg/L was measured as MIC. Thus, low cost and facile preparation strategy for fabrication of ZnO2 nanoparticles merged with their effective antibiotic activity will open a door for further utilizing this kind of peroxide nanomaterials in other biological applications.

Low-temperature growth of graphene nanoplatelets by hot-wire chemical vapour deposition

With the increasing demand for large-area graphene due to its versatility, there is an imminent requirement for scalable, low-temperature, and high yield growth procedures. In this study, the fabrication of large-area graphene nanoplatelets directly grown on tungsten (W) nanoparticles coated c-Si and quartz substrates by hot-wire chemical vapour deposition was demonstrated. A large area of single and bilayer graphene grown over W adatoms via controlled argon (Ar) plasma treatment varied from 0.5 to 10 min. The finest quality of continuous graphene layer up to an area of 2.56 × 104 μm2 was prepared at the optimised condition of 1 min, and verified through transmission electron microscopy in conjunction with energy dispersive X-ray, atomic force microscopy, and Raman spectroscopy. The prepared thin film of the carbon layer has excellent optical transparency (> 70%) and lower sheet resistance up to 718.3 Ω/sq. A detailed growth mechanism is proposed for the nucleation of graphene nanoplatelets under the influence of Ar plasma treatment on W nanoparticles.

Mechanistic Investigations of Growth of Anisotropic Nanostructures in Reverse Micelles.

Tailoring the characteristics of anisotropic nanostructures like size, morphology, aspect ratio, and size dispersity is of extreme importance due to the unique and tunable properties including catalytic, optical, photocatalytic, magnetic, photochemical, electrochemical, photoelectrochemical, and several other physical properties. The reverse microemulsion (RM) method offers a useful soft-template and low-temperature procedure that, by variation of experimental conditions and nature of reagents, has proved to be extremely versatile in synthesis of nanostructures with tailored properties. Although many reports of synthesis of nanostructures by the RM method exist in the literature, most of the research studies carried out still follow the “hit and trial” method where the synthesis conditions, reagents, and other factors are varied and the resulting characteristics of the obtained nanostructures are justified on the basis of existing physical chemistry principles. Mechanistic investigations are scarce to generate a set of empirical rules that would aid in preplanning the RM-based synthesis of nanostructures with desired characteristics as well as make the process viable on an industrial scale. A consolidation of such research data available in the literature is essential for providing future directions in the field. In this perspective, we analyze the literature reports that have investigated the mechanistic aspects of growth of anisotropic nanostructures using the RM method and distil the essence of the present understanding at the nanoscale timescale using techniques like FCS and ultrafast spectroscopy in addition to routine techniques like DLS, fluorescence, TEM, etc.

Synthesis of oxygen-doped-g-C3N4/WO3 porous structures for visible driven photocatalytic H2 production

Noble-metal-free sustainable energy conservation has been attracting considerable attention for environmental protection and remediation. Herein, we present a low-temperature (<100 °C) procedure for fabricating porous oxygen-doped g-C3N4/WO3 structures with H2O2, oxygen doping creates the trap energy levels which are more sensitive towards visible light and studied their photocatalytic H2 evaluation under visible light irradiation. The oxygen generates CO, N–O, C–O–W, and C–O–W–N, which can alter the oxidation state of tungsten and boost-up the photocatalytic properties of O-g-C3N4/WO3. The optimized photocatalyst (O-g-CNW-4) produces higher H2 evaluation (15,142 μmol/g), which is 4.7 times higher than that produced by mechanical mixing samples. The prepared samples have highly porous structures with pore diameters of 20–30 nm. The CO, N–O, C–O–W, and C–O–W–N linkage vibrations of the prepared samples are analyzed, and their chemical confirmations and elemental oxidation states are verified. The oxygen-doped g-C3N4/WO3 porous structures exhibit large surface-areas with a huge quantity of active surface sites, band-structure modulation, and effective visible-light-harvesting of the photoinduced charge carriers, which is useful for enhancing photocatalytic H2 production.

Cryotherapy for the prevention of chemotherapy-induced peripheral neuropathy: A systematic review.

Chemotherapy induced peripheral neuropathy (CIPN) is an adverse effect of certain chemotherapy agents that can result in dose reductions, permanent nerve damage, and chronic pain. Although pharmacological agents have been studied in this setting, there is no standard of care for the prevention of CIPN. Thus, the objective of this systematic review is to assess the efficacy and safety of cryotherapy for the prevention of CIPN. PubMed (1946 to February 2020) and Embase (1947 to February 2020) were utilized to conduct a literature search using the following search terms: antineoplastic agent(s), taxoid(s), or chemotherapy and neuralgia, peripheral nervous system diseases, peripheral neuropathy, or paclitaxel-induced peripheral neuropathy and cryotherapy, cryotherapy device, hypothermia, low temperature procedures, or ice. A total of 11 studies were included in the final assessment. Results of this systematic review indicate that the efficacy of cryotherapy in preventing CIPN is conflicting. This may be due to studies utilizing differing cryotherapy administration methods, study design, and including only a small number of patients. All included studies utilized cryotherapy with taxane-based chemotherapy treatments and cooling gloves and socks was the most common method of administration. Overall, cryotherapy was well-tolerated and no serious adverse effects were noted. Due to the absence of serious adverse effects, cryotherapy is a reasonable option to consider to prevent CIPN in patients receiving taxane-based chemotherapy. However, additional research is needed, including larger, better designed studies, to fully delineate the role of cryotherapy for CIPN.

Low-temperature processed, stable n-i-p perovskite solar cells with indene-C60-bisadduct as electron transport material

Organo-metallic halide perovskites (OMHP) have proven to be promising light absorbers with superb optoelectronic properties for developing the next generation of low-cost solar cells. Over the past years, the extensive research efforts on perovskite solar cells (PSCs) have led to an impressive improvement in the photovoltaic performance on many fronts and have their main field of applications in low-temperature and low power consumption photo-electronic devices, However, a wide range of highly performing PSCs structures involves the use of metal oxide electron transport materials (ETMs) such as TiO2 which requires high processing temperature that could result in a higher manufacturing energy input and cost. This also could hinder the development of low-cost and low-temperature scalable processes for device fabrication on rigid or flexible substrates. Here, we develop a low-temperature procedure (below 100 °C) that make use of Indene-C60 Bisadduct (ICBA) as an alternative ETM in the planar n-i-p-structured PSCs. After modifying the ICBA layer, we not only improved the optimum performance and stability of the device, but also study its influence on the device operation using impedance spectroscopy, and finally achieved a stabilized power conversion efficiency of 13.5%. Thereby, this study will establish low-temperature ETM as an outstanding candidate for future high stability PSCs production due to its high performance, low process temperature and easy fabrication.

Synthesis of upconversion TiO2:Er3+-Yb3+ nanoparticles and deposition of thin films by spin coating technique

In this work, a simple, low temperature (T < 300 °C) procedure suitable to increase the efficiency of solar cell and optoelectronic devices through reducing the mismatch with solar spectrum in the infrared range is proposed. TiO2 co-doped with rare earth ions is a promising candidate for its use in optical field due to the possibility to expand the spectral absorption range. Here, pure and Er3+-Yb3+co-doped anatase-TiO2 nano-spherical particles (diameter < 50 nm) with high surface area (125.7 m2/g and 140.6 m2/g for the pure and co-doped, respectively), good crystallinity are prepared by hydrothermal-assisted sol-gel method, followed by their dispersion and deposition as thin films. The nanoparticles are characterized by studying their structural, morphology, surface chemical compositions and photoluminescent properties. From the dispersion study, results showed that the optimal conditions were obtained for co-doped TiO2 at operational pH = 3 and with 20 min as a suitable duration of ultrasonication. The co-doped TiO2 nanoparticles showed excellent upconversion properties (green and red emissions) at room temperature under 980 nm excitation. To extend this result towards optoelectronic and photonic applications, the upconversion nanoparticles are deposited at the surface of n-type (100) Si wafer using a spin-coating process. From scanning electron microscopy, it is observed that the entire surface of substrate is covered with a uniform film composed of compact arrangement of small nanoparticles with a good adhesion on Si surface, also the resulting 750 nm thick TiO2:Er–Yb film maintained the upconversion luminescence phenomena.

Low-temperature mineralization sintering process for fabrication of fluoridated hydroxyapatite-containing bioactive glass

Bioactive glasses and glass-ceramics are receiving wide attention for their biomedical applications. We present a novel route to obtain fluoridated hydroxyapatite-containing bioactive glass (FHBG) through a low-temperature mineralization sintering process (LMSP). LMSP is a low-temperature densification procedure that can provide a functionalization of pristine materials through the formation and growth of new phases induced by mineralization. Here, SiO2–CaO–P2O5 bioactive glass nanoparticles (BGNPs) were prepared and mixed with fluorine-containing simulated body fluid (F–SBF) to induce mineralization. Under a uniaxial pressure of 330 MPa and temperature of 120 °C, BGNPs were densified up to 89% of their theoretical density, and the Vickers hardness and fracture toughness of the sintered BGNPs increased to 4.15 ± 0.11 GPa and 1.32 ± 0.12 MPa m1/2, respectively. This densification behavior was strongly influenced by the mineralization that forms nanoscale crystalline phase such as carbonated fluoridated hydroxyapatite (HAp), where part of PO43− and OH− in HAp (Ca10(PO4)6(OH)2) was replaced by CO32− and F−, respectively. The fluorides formed as minor phases in the sintered BGNPs by mineralization were identified as calcium fluorosilicate (CaSiF6) and calcium fluoride (CaF2). After an acid resistance test, because of the presence of fluorides, the sintered BGNPs containing fluorides presented a 38% weight loss, which is lower than that of sintered BGNPs containing no fluorides (54% weight loss). By employing LMSP, we successfully fabricated FHBG from non-fluoride-containing BGNPs and F–SBF at an extremely low temperature at 120 °C. Therefore, this study offers a more efficient method for the manufacturing of glasses and glass-ceramics.

Low temperature microwave fabrication of three-dimensional graphene/polyimide foams with flexibility strain responsivity

The mechanical brittleness and structure collapse of three-dimensional (3D) graphene composite construction is still an enormous issue in flexible performance of complex. In addition, low temperature and efficient process become increasingly significant and noticeable in field of semiconductor device to prevent from huge resource waste and energy consumption. Herein, we report a special method to prepare 3D graphene/polyimide (rGO/PI) aerogel with low temperature and rapid procedure. The aerogel is synthesized by introducing water-soluble polyamic acid ionic salt (PAS) and ice-templating directional solidification to establish unique oriented structure, and by energy-efficient microwave to realize low temperature and rapid imidization. The preparative rGO/PI nanocomposite aerogels hold excellent electrical conductivity, desirable flexibility, superior pressure-responsive properties, remarkable compression sensitivity and durability, so that adapt to multifarious deformations with huge potential for flexible wearable devices.

Crystalline D-π-D porphyrin molecules as a hole-transporting material for printable perovskite solar cells

Crystalline, electrically conductive molecules that transport charge carriers efficiently are candidates for next–generation printable optoelectronic devices. Here, we have designed a series of D-π-D porphyrin molecular systems as either a free-base or with coordinated metals (Cu and Zn) via high yield, low-temperature synthetic procedures. The D-π-D porphyrin molecular systems (coded as HPPHT, CPPHT and ZPPHT) were comprehensively investigated employing electrical and electrochemical methods, optical absorption spectroscopy, XRD, and XPS to identify their energy levels, optical, electrical and structural properties. The studies revealed that the D-π-D porphyrin molecular systems were crystalline, with desirable energy levels and superior electrical properties compared to the benchmark Spiro-OMeTAD under similar conditions. Among these molecular systems, CPPHT exhibited an activation energy of 0.13 eV and a higher charge carrier density (Nd ~ 4.84 × 1013 cm−3), when compared to the HPPHT (4.20 × 1011 cm−3, 0.13 eV) and ZPPHT (1.92 × 1012 cm−3, 0.17 eV) systems. These molecular systems were introduced as hole transport materials into pre-made perovskite solar cells (without a HTM) by a simple infiltration process via the front contact layer. Among the three systems studied, CPPHT solar cells showed the highest photo-current density (Jsc) of 20.44 mA·cm−2 and power conversion efficiency (PCE) of 11.76% when compared with the H/ZPPHT devices under AM 1.5G (100 mW·cm−2) illumination; signifying lower recombination at the interface of the CPPHT/perovskite (MAPbI3). Incorporation of Li-TFSI/t-BP additives on the device surface improved the HTM-MAPbI3 interface, and increased the Jsc to 21.35 mA·cm−2 with a PCE of 12.88% for CPPHT devices. These D-π-D porphyrin molecular systems under ambient conditions demonstrated excellent short-term and operational stability in the presence of moisture. The modified device architecture opens up a novel configuration for designing high–performance optoelectronic devices.

Visible-Light-Driven Nitrogen Fixation Catalyzed by Bi5O7Br Nanostructures: Enhanced Performance by Oxygen Vacancies.

Photocatalytic nitrogen fixation represents a green alternative to the conventional Haber-Bosch process in the conversion of nitrogen to ammonia. In this study, a series of Bi5O7Br nanostructures were synthesized via a facile, low-temperature thermal treatment procedure, and their photocatalytic activity toward nitrogen fixation was evaluated and compared. Spectroscopic measurements showed that the tubular Bi5O7Br sample prepared at 40 °C (Bi5O7Br-40) exhibited the highest electron-transfer rate among the series, producing a large number of O2.- radicals and oxygen vacancies under visible-light photoirradiation and reaching a rate of photocatalytic nitrogen fixation of 12.72 mM·g-1·h-1 after 30 min of photoirradiation. The reaction dynamics was also monitored by in situ infrared measurements with a synchrotron radiation light source, where the transient difference between signals in the dark and under photoirradiation was analyzed and the reaction pathway of nitrogen fixation was identified. This was further supported by results from density functional theory calculations. The reaction energy of nitrogen fixation was quantitatively estimated and compared by building oxygen-enriched and anoxic models, where the change in the oxygen vacancy concentration was found to play a critical role in determining the nitrogen fixation performance. Results from this study suggest that Bi5O7Br with rich oxygen vacancies can be used as a high-performance photocatalyst for nitrogen fixation.

Extraction of Hydroxyapatite Nanostructures from Marine Wastes for the Fabrication of Biopolymer-Based Porous Scaffolds.

Three-dimensional porous nanocomposites consisting of gelatin-carboxymethylcellulose (CMC) cross-linked by carboxylic acids biopolymers and monophasic hydroxyapatite (HA) nanostructures were fabricated by lyophilization, for soft-bone-tissue engineering. The bioactive ceramic nanostructures were prepared by a novel wet-chemical and low-temperature procedure from marine wastes containing calcium carbonates. The effect of surface-active molecules, including sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB), on the morphology of HA nanostructures is shown. It is demonstrated that highly bioactive and monophasic HA nanorods with an aspect ratio > 10 can be synthesized in the presence of SDS. In vitro studies on the bioactive biopolymer composite scaffolds with varying pore sizes, from 100 to 300 μm, determine the capacity of the developed procedure to convert marine wastes to profitable composites for tissue engineering.

Amorphous hybrid TiO2 thin films: The role of organic ligands and UV irradiation

The development of a simple, economic and low-temperature synthesis procedure for titanium oxide thin films is an important challenge, due to their diffusion and to the limitations imposed by high temperature annealing. The knowledge on the properties of amorphous TiO2 films, as well as on the effect of their functionalization by organic compounds, is still inadequate. Here we describe a hydrolytic sol-gel procedure to prepare TiO2-based hybrid (inorganic-organic) thin films containing four different complexing agents in their structure (acetylacetone, dibenzoylmethane, citric acid and diethanolamine). The process variables were explored in order to attain stable sols and to tune the features of the amorphous films resulting by drying at 80 °C. Their structural, morphological, optical and electrical properties were studied by SEM, AFM, XRD, ellipsometry, FT-IR and UV–vis-NIR spectroscopy and resistivity measurements. The effect of the organic component, precursors concentration, deposition parameters and annealing temperature was considered. Moreover, the modifications induced by the exposure of the hybrid films to UV light were deeply investigated. A short UV treatment has a strong impact on the microstructure and wettability of the films and promotes a striking increase in their electrical conductivity.

Use of Chelate Complexes of Lead(II) in Low-Temperature Technologies of Ceramic Piezoelectric Materials

Technology is suggested for fabrication of ceramic piezoelectric materials from the lead-containing ferroelectric phase. The technology includes a low-temperature synthesis of ultradispersed lead titanate and zirconate powders and also of phases of solid solutions on their basis and the low-temperature procedure for sintering of ceramic fabricated from ultradispersed powders of ferroelectric phases. As precursors used in the suggested low-temperature synthesis serve lead glycerate and tartrate. It was found that, when interacting (at temperatures of 240–330°C) with hydroxo-peroxo-aqua complexes of titanium and(or) zirconium(IV) in the course of 30–40 min, the precursors form ultradispersed powders of these phases, which are single-phase and contain particles with average size of less than 100 nm. It was shown that using the suggested technology makes it possible not only to reduce the energy expenditure for separate procedures for synthesis of ultradispersed ferroelectric phases and for synthesis of piezoelectric materials, but also to substantially diminish the discharge of lead(II) compounds into the atmosphere of industrial premises. It was also shown that the technology enables fabrication of piezoelectric materials with prescribed values of electrical parameters.