Reaction mechanism of producing barium hexaferrites from γ-Fe2O3 and Ba(OH)2 by hydrothermal method

Hydrothermal Synthesis of Ba‐Hexaferrite Nanoparticles

“…The iron ions must be agglomerated in larger aggregates, which then react with hydrated barium ions. In a very alkaline medium, [Fe(OH) 4 ] x − x are formed, which then form intermediate complexes 21 and subsequently the target compounds. Hence, in reality, most probably the [Fe(OH) 4 ] x − x (aq ) and Ba 2+ ( aq ) are the constituent species that govern the formation of BaFe 12 O 19 .…”

“…In the past, efforts have concentrated on searching for the appropriate conditions to obtain a high‐quality Ba‐hexaferrite product 19,20 and to understand the reaction mechanisms and the kinetics involved during the hydrothermal processing of Ba‐hexaferrite 21–25 …”

Synthesis of nanocrystalline Ba(MnTi)xFe12−2xO19 powders by the sol–gel combustion method in citrate acid–metal nitrates system (x=0, 0.5, 1.0, 1.5, 2.0)

“…For example, the dry method, the hydrothermal reaction [9][10][11], the chemical co-precipitation [12][13][14][15], the aerosol pyrolysis [16], the sol-gel technique [17][18][19], the glass crystallization method [20][21][22], the low temperature combustion syntheses (LCS) [23,24] and aqueous combustion synthesis (ACS) [25][26][27]. An ideal method to make BaM hexaferrites should include the following: facile operation, low anneal or calcine temperature, energy-efficient, and a short reaction time.…”

Remanence properties of barium hexaferrite

“…In fact, this material presents high saturation magnetization, high Curie temperature, high intrinsic coercivity and rather large crystal magnetic field anisotropy [1,2]. Due to these properties, many methods of synthesis have been developed to obtain a low production cost of fine particles of barium ferrite with a good chemical homogeneity, in this sense coprecipitation seems to be the most suitable at the moment [2][3][4][5]. However it is of great importance the level of stacking of Ba ferrite particles which is believed to determine the magnetic interparticle interactions, affecting essential properties such as thermal duplication, media noise and resolution in longitudinal recording media [1,6].…”