Effect of carbon shell on stabilization of single-phase lanthanum and praseodymium hexaaluminates prepared by a modified Pechini method

Stoyanovskii, Vladimir O.; Vedyagin, Aleksey A.; Володин, А. М.; Bespalko, Yulia

doi:10.1016/j.ceramint.2020.08.088

Cited by 7 publications

(5 citation statements)

References 47 publications

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“…Bi 2 Ce 2 O 7 and Bi 1.6 Y 0.4 Ce 2 O 7 were synthesized via the modified Pechini technique, as described elsewhere [ 43 ]. For the Bi 1.6 Y 0.4 Ti 2 O 7 sample synthesized by the citrate method, corresponding salts in the required ratios were added to a solution of citric acid in water (1;5 mole ratio), while the Me:citric acid ratio was equal to 1:2.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Oxygen Mobility of Bismuth Cerates and Titanates with Pyrochlore Structure

et al. 2023

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Synthesis and study of materials based on bismuth cerates and titanates were carried out. Complex oxides Bi1.6Y0.4Ti2O7 were synthesized by the citrate route; Bi2Ce2O7 and Bi1.6Y0.4Ce2O7—by the Pechini method. The structural characteristics of materials after conventional sintering at 500–1300 °C were studied. It is demonstrated that the formation of a pure pyrochlore phase, Bi1.6Y0.4Ti2O7, occurs after high-temperature calcination. Complex oxides Bi2Ce2O7 and Bi1.6Y0.4Ce2O7 have a pyrochlore structure formed at low temperatures. Yttrium doping of bismuth cerate lowers the formation temperature of the pyrochlore phase. As a result of calcination at high temperatures, the pyrochlore phase transforms into the CeO2-like fluorite phase enriched by bismuth oxide. The influence of radiation-thermal sintering (RTS) conditions using e-beams was studied as well. In this case, dense ceramics are formed even at sufficiently low temperatures and short processing times. The transport characteristics of the obtained materials were studied. It has been shown that bismuth cerates have high oxygen conductivity. Conclusions are drawn about the oxygen diffusion mechanism for these systems. The materials studied are promising for use as oxygen-conducting layers in composite membranes.

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Section: Methodsmentioning

confidence: 99%

Synthesis and Oxygen Mobility of Bismuth Cerates and Titanates with Pyrochlore Structure

et al. 2023

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“…The ultimate goal is to optimize and expand the applicability of HAs, not the least in the field of catalysis. 428 Although significant synthetic progress has been made, the development of a robust, costeffective, and environmentally benign method that requires minimized calcination temperatures remains an ambitious challenge. 311 5.4.…”

Section: Synthesis Methods Formentioning

confidence: 99%

“…In summary, the search for a facile, reproducible and scalable synthesis method that produces HAs with small particle sizes and adequate surface areas is an ongoing task. The ultimate goal is to optimize and expand the applicability of HAs, not the least in the field of catalysis . Although significant synthetic progress has been made, the development of a robust, cost-effective, and environmentally benign method that requires minimized calcination temperatures remains an ambitious challenge …”

Section: Lanthanum Hexaaluminate (Lha)mentioning

confidence: 99%

“…Higher surface areas are clearly seen for samples prepared in microemulsions (entries 54–58) ,,− (e.g., 67 m 2 /g in entry 58). Further methods to obtain LHA include precipitation (as opposed to coprecipitation, entry 26), solid-state reactions (entries 1–6), ,,,,,− ion-exchange or impregnation of aluminas or alumoxane with decomposable La-salts (entries 7–14), ,, , , , ,, Pechini method (entries 15, 17, 18), , , , carbon templating (entries 19–21), , , , as well as combustion and oxidation routes (entries 22–25). , , , With respect to surface areas, only a combined Pechini/carbon-templating route (entry 18, 90 m 2 /g) can compete with synthesis in microemulsions. Remarkably, in none of the entries in Table S1, a molar Al/La ratio of 14.2, corresponding to the genuine Al/La ratio in LHA, is used in the starting material.…”

Section: Lanthanum Hexaaluminate (Lha)mentioning

confidence: 99%

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La-Doped Alumina, Lanthanum Aluminate, Lanthanum Hexaaluminate, and Related Compounds: A Review Covering Synthesis, Structure, and Practical Importance

Heveling

2023

Ind. Eng. Chem. Res.

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Advanced materials based on lanthanum–aluminum oxides are useful for many practical applications, not the least in catalysis, energy conversion and energy storage systems designed for a sustainable world economy. The three main La–Al–O (LAO) combinations of commercial interest are La-doped aluminas (LDA), lanthanum monoaluminate (LMA, a perovskite), and lanthanum hexaaluminate (LHA). Usually, the literature treats doped aluminas, perovskites, and hexaaluminates separately. The current review tries to identify common trends and features with respect to structure, synthesis, and applications of LAOs, which should lead to a more holistic understanding of their chemistry. This, in turn, should trigger innovative ideas with respect to new or improved applications. Apart from a variety of uses at low temperatures, the main advantages of LDA, LMA, LHA, and related compounds are their high-temperature stability and the extended applicability that comes with it.

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“…Properties, such as interfacial polarization and corrosion resistance [ 19 ] are also improved. One can observe that shells may enhance the phase stability of cores at elevated temperatures, see [ 20 , 21 , 22 ] for example. Protective coatings may be applied, not only on individual particles, but also on microwires [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

Deposition of Thick SiO2 Coatings to Carbonyl Iron Microparticles for Thermal Stability and Microwave Performance

Dolmatov¹,

Maklakov²,

Artemova³

et al. 2023

Sensors

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Thick dielectric SiO2 shells on the surface of iron particles enhance the thermal and electrodynamic parameters of the iron. A technique to deposit thick, 500-nm, SiO2 shell to the surface of carbonyl iron (CI) particles was developed. The method consists of repeated deposition of SiO2 particles with air drying between iterations. This method allows to obtain thick dielectric shells up to 475 nm on individual CI particles. The paper shows that a thick SiO2 protective layer reduces the permittivity of the ‘Fe-SiO2—paraffin’ composite in accordance with the Maxwell Garnett medium theory. The protective shell increases the thermal stability of iron, when heated in air, by shifting the transition temperature to the higher oxide. The particle size, the thickness of the SiO2 shells, and the elemental analysis of the samples were studied using a scanning electron microscope. A coaxial waveguide and the Nicholson–Ross technique were used to measure microwave permeability and permittivity of the samples. A vibrating-sample magnetometer (VSM) was used to measure the magnetostatic data. A synchronous thermal analysis was applied to measure the thermal stability of the coated iron particles. The developed samples can be applied for electromagnetic compatibility problems, as well as the active material for various types of sensors.

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Effect of carbon shell on stabilization of single-phase lanthanum and praseodymium hexaaluminates prepared by a modified Pechini method

Cited by 7 publications

References 47 publications

Synthesis and Oxygen Mobility of Bismuth Cerates and Titanates with Pyrochlore Structure

Synthesis and Oxygen Mobility of Bismuth Cerates and Titanates with Pyrochlore Structure

La-Doped Alumina, Lanthanum Aluminate, Lanthanum Hexaaluminate, and Related Compounds: A Review Covering Synthesis, Structure, and Practical Importance

Deposition of Thick SiO2 Coatings to Carbonyl Iron Microparticles for Thermal Stability and Microwave Performance

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