Characteristics of barium hexaferrite nanocrystalline powders prepared by a sol-gel combustion method using inorganic agent

Abstract

Nanocrystalline particles of barium hexaferrite were synthesized by a sol-gel combustion route using nitrate-citrate gels prepared from metal nitrates and citric acid solutions under various Fe/Ba molar ratios of 10, 11 and 12. Sodium hydroxide was used as a pH-adjusting agent. The results revealed that the formation temperature of barium hexaferrite is influenced by Fe/Ba molar ratio; the Fe/Ba molar ratio of 12 is more favorable. For sample synthesized with a Fe/Ba molar ratio of 12, barium hexaferrite started to form at 800°C and fully formed at 1000°C. The results also showed that the coercivity of the samples decreases as the Fe/Ba molar ratio increases from 10 to 12, whilst the saturation magnetization increases.

Current developments in green synthesis of metallic nanoparticles using plant extracts: a review

“…In bottom-top approaches, the synthesis process start with the self-assembly of atoms/molecules into nuclei and afterwards the formation of particles in the nanoscale range (Figure 2(c)) [9] i.e. co-precipitation, sol-gel, and atomic condensation [12][13][14] are examples of this approach. The bottom-top synthesis mostly relies on chemical and biological methods of production.…”

Microstructure and magnetic properties of Al-doped barium ferrite with sodium citrate as chelate agent

“…What is worse, it generally introduces impurities, which cause the lattice strain in the crystal structure. In order to get ultrafine particle sizes, a narrow size distribution and chemical homogeneity at low temperature, many chemical methods, such as reverse micelle technique, co-precipitation and sol-gel route, were carried out to synthesize BaM [14][15][16]. The advantage of these chemical methods was the intimate reaction of the starting materials on an ionic level so that the crystallization took place at low temperature, giving rise to sample with a narrow size distribution and excellent magnetic properties.…”

“…The advantage of these chemical methods was the intimate reaction of the starting materials on an ionic level so that the crystallization took place at low temperature, giving rise to sample with a narrow size distribution and excellent magnetic properties. During the chemical procedures, lots of inorganic or organic agents were used to chelate Ba 2 þ and Fe 3 þ [15,16]. Sodium citrate, which is a low molecular weight chemicals, can promote homogeneous mixing of metal ions on atomic level of as-synthesized multicomponent compounds [17].…”