Perovskite membranes by aqueous combustion synthesis: synthesis and properties

Abstract

The objective of this work is to identify optimum synthesis, compacting and sintering conditions in order to achieve a pure phase fully densified La 0.8 Sr 0.2 CrO 3 (LSC) perovskite membrane. The aqueous combustion synthesis of LSC powders was investigated over a wide range of synthesis conditions by using the metal nitrates (oxidizer)-glycine (fuel) system. The powders were pressed and sintered to create dense materials, which were characterized. It was shown that depending on fuel/oxidizer ratio, , the reaction can proceed in three different modes: Smoldering Combustion Synthesis (SCS), B0.7, with maximum temperature, T m B 600°C; Volume Combustion Synthesis (VCS), 0.7 B B1.2, 1150°C B T m B1350°C; Self-propagating High-temperature Synthesis (SHS), 1.2 B B 1.6, 800°CBT m B1100°C. In turn, the characteristics of synthesized powders depend on the combustion mode. The crystalline structure of as-synthesized powders becomes more defined as increases (amorphous for SCS; crystalline for VCS and SHS). The specific surface area decreases slightly when mode changes from SCS ( 25 m 2 g − 1 ) to VCS ( 20 m 2 g − 1 ), however, it increases substantially under SHS conditions (up to 45 m 2 g − 1 ). It was also shown that calcination is beneficial only for SCS powders, while VCS and SHS powders may be sintered directly as synthesized, thus bypassing the time and energy consuming calcination step. The measured oxygen permeation values for the membranes are comparable with the best candidate materials reported in the literature.

Physico-Chemical Study of Coating Formulation Based on Natural Apatite for the Elaboration of Microfiltration Membrane

“…Advantages of ceramic membranes include resistance to corrosive feed, high temperature applicability, consistency in high pressure application and long life [1,2]. The major challenges for future development of inorganic membranes are to produce low-cost membranes from natural materials such as clay and apatite which are in abundance, need lower firing temperature than metal oxide materials and have high separation performances suitable for treatment of large volumes of liquid [2][3][4][5]. To increase the reliability of the tenacity of these membranes having an asymmetric structure composed of at least two layers which are the support and the active layer, there is still a need for improvement in rheological properties of dip solution required for the preparation of microfiltration membrane layer.…”

“…Apatite possesses a wide range of physicochemical properties and is used as raw material in many chemical industries such as the preparation of the artificial fertilisers, manufacture of catalysts, osseous prostheses. The system hydroxyapatiteadditives is usually used in the manufacture of bioceramics and for the potential application for preparing ceramic membranes [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The properties of the apatite suspensions in water are largely modified by the presence of polymers, electrolytes, etc.…”

Cromito de lantânio: material para interconectores de células a combustível de óxido sólido - uma revisão

“…Comparando a rota de síntese por combustão com as técnicas de mistura de óxidos e Pechini, foi observado que os pós obtidos por combustão apresentam maior sinterabilidade do que os pós obtidos pelas outras técnicas [104]. Vários pesquisadores utilizaram meios reacionais distintos na síntese por reação de combustão para se obter o cromito de lantânio dopado, destacando-se os trabalhos das referências [40,61,62,107,[108][109][110][111][112][113][114].…”

Solution combustion synthesis of α-Al2O3 using urea

“…According to Mukasyan et al [27], the dependence of the synthesis on j is described by different mechanisms: when j $ 1.2-2 (fuel-rich regime), the reaction is locally ignited and propagates as a combustion wave in a selfsustained manner throughout the reaction volume. In this regime, atmospheric oxygen is required for a complete combustion between the fuel and the metal nitrates.…”

“…In particular the unknown cause of the lack of smouldering combustion synthesis in the reactant mixture when j o 0.8 [27]. In this article, we have investigated the conditions of the synthesis of a-alumina powders near the stoichiometric fuel/oxidant ratio (j $ 0.8-1.2) using urea as a fuel and aluminium nitrate as an oxidiser.…”