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Rapid and direct synthesis of complex perovskite oxides through a highly energetic planetary milling

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ABSTRACT

The search for a new and facile synthetic route that is simple, economical and environmentally safe is one of the most challenging issues related to the synthesis of functional complex oxides. Herein, we report the expeditious synthesis of single-phase perovskite oxides by a high-rate mechanochemical reaction, which is generally difficult through conventional milling methods. With the help of a highly energetic planetary ball mill, lead-free piezoelectric perovskite oxides of (Bi, Na)TiO3, (K, Na)NbO3 and their modified complex compositions were directly synthesized with low contamination. The reaction time necessary to fully convert the micron-sized reactant powder mixture into a single-phase perovskite structure was markedly short at only 30–40 min regardless of the chemical composition. The cumulative kinetic energy required to overtake the activation period necessary for predominant formation of perovskite products was ca. 387 kJ/g for (Bi, Na)TiO3 and ca. 580 kJ/g for (K, Na)NbO3. The mechanochemically derived powders, when sintered, showed piezoelectric performance capabilities comparable to those of powders obtained by conventional solid-state reaction processes. The observed mechanochemical synthetic route may lead to the realization of a rapid, one-step preparation method by which to create other promising functional oxides without time-consuming homogenization and high-temperature calcination powder procedures.

No MeSH data available.


Comparison of the cumulative kinetic energy Ecum and the milling time t taken from the literature (Table 1) with those used in this work.The literature data were limited to those corresponding to the dominant formation of perovskite oxides.
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f6: Comparison of the cumulative kinetic energy Ecum and the milling time t taken from the literature (Table 1) with those used in this work.The literature data were limited to those corresponding to the dominant formation of perovskite oxides.

Mentions: This relationship implies that Ecum is highly sensitive to Wp with linear Wp3 dependence; see the fitted curves of Ecumvs. Wp in Fig. 6 when t = 1, 2 and 3 h. In this figure, the literature data pertaining to Ecum and t required for the dominant formation of various perovskite oxides are also presented and compared to those used in this work. The prolonged period of milling between 20–400 h needed in many mechanochemical studies is attributed to the lower level of Wp (200–300 rpm). For instance, the milling time of 400 h required to reach an Ecum value of 2592 kJ/g at a disk speed of 200 rpm (used in ref. 23) can be dramatically reduced to less than 3 h when adopting condition number 2 as defined in this work.


Rapid and direct synthesis of complex perovskite oxides through a highly energetic planetary milling
Comparison of the cumulative kinetic energy Ecum and the milling time t taken from the literature (Table 1) with those used in this work.The literature data were limited to those corresponding to the dominant formation of perovskite oxides.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384223&req=5

f6: Comparison of the cumulative kinetic energy Ecum and the milling time t taken from the literature (Table 1) with those used in this work.The literature data were limited to those corresponding to the dominant formation of perovskite oxides.
Mentions: This relationship implies that Ecum is highly sensitive to Wp with linear Wp3 dependence; see the fitted curves of Ecumvs. Wp in Fig. 6 when t = 1, 2 and 3 h. In this figure, the literature data pertaining to Ecum and t required for the dominant formation of various perovskite oxides are also presented and compared to those used in this work. The prolonged period of milling between 20–400 h needed in many mechanochemical studies is attributed to the lower level of Wp (200–300 rpm). For instance, the milling time of 400 h required to reach an Ecum value of 2592 kJ/g at a disk speed of 200 rpm (used in ref. 23) can be dramatically reduced to less than 3 h when adopting condition number 2 as defined in this work.

View Article: PubMed Central - PubMed

ABSTRACT

The search for a new and facile synthetic route that is simple, economical and environmentally safe is one of the most challenging issues related to the synthesis of functional complex oxides. Herein, we report the expeditious synthesis of single-phase perovskite oxides by a high-rate mechanochemical reaction, which is generally difficult through conventional milling methods. With the help of a highly energetic planetary ball mill, lead-free piezoelectric perovskite oxides of (Bi, Na)TiO3, (K, Na)NbO3 and their modified complex compositions were directly synthesized with low contamination. The reaction time necessary to fully convert the micron-sized reactant powder mixture into a single-phase perovskite structure was markedly short at only 30–40 min regardless of the chemical composition. The cumulative kinetic energy required to overtake the activation period necessary for predominant formation of perovskite products was ca. 387 kJ/g for (Bi, Na)TiO3 and ca. 580 kJ/g for (K, Na)NbO3. The mechanochemically derived powders, when sintered, showed piezoelectric performance capabilities comparable to those of powders obtained by conventional solid-state reaction processes. The observed mechanochemical synthetic route may lead to the realization of a rapid, one-step preparation method by which to create other promising functional oxides without time-consuming homogenization and high-temperature calcination powder procedures.

No MeSH data available.