Structure and magnetic properties of nanosized magnetite obtained by glass recrystallization

Optical, magnetic and electrical properties of new ceramics/lead silicate glass composites recycled from lead crystal wastes

Nowadays, the disposal of industrial wastes is an ablaze issue worldwide, especially those containing hazardous materials. Lead silicate glass waste (LSG) produced during lead crystal glass manufacturing, which contains about 30% of toxic lead compounds, belongs to this category. This work aims to adopt an innovative clean method to convert this waste into novel advanced ceramic materials via an environmental friendly method. Chromia Cr₂O₃ and hematite Fe₂O₃ ceramics with different content (0, 5, 10, 15%) are added separately to the solid wastes of LSG recovered from national crystal glass industry to obtain various ceramics/LSG composites by pressureless sintering methods. Different properties of the produced composites are evaluated in terms of phase's identification and microstructural features. Optical properties in terms of absorbance, reflectance, band gap (E_g), refractive index (n) and photoluminescence (PL) are investigated. Magnetic and electrical properties are inclusively studied. Results indicated that, an addition of chromia and hematite as well as increasing their content to 15% has enhanced the microstructural features, optical, electrical and magnetic properties of the obtained composites. Cr₂O₃/LSG composites are considered as promising optical and electrical materials. However, Fe₂O₃/LSG composites showed the highest optical and magnetic properties. They are strongly recommended in optoelectronic and magneto-optical applications.

The Influence of Synthesis Parameters on Structural and Magnetic Properties of Iron Oxide Nanomaterials

Magnetic iron oxides have been used in biomedical applications, such as contrast agents for magnetic resonance imaging, carriers for controlled drug delivery and immunoassays, or magnetic hyperthermia for the past 40 years. Our aim is to investigate the effect of pressure and temperature on the structural, thermal, and magnetic properties of iron oxides prepared by hydrothermal synthesis at temperatures of 100–200 °C and pressures of 20–1000 bar. It has been found that pressure influences the type of iron oxide crystalline phase. Thus, the results obtained by Mössbauer characterization are in excellent agreement with X-ray diffraction and optical microscopy characterization, showing that, for lower pressure values (<100 bar), hematite is formed, while, at pressures >100 bar, the major crystalline phase is goethite. In addition, thermal analysis results are consistent with particle size analysis by X-ray diffraction, confirming the crystallization of the synthesized iron oxides. One order of magnitude higher magnetization has been obtained for sample synthesized at 1000 bar. The same sample provides after annealing treatment, the highest amount of good quality magnetite leading to a magnetization at saturation of 30 emu/g and a coercive field of 1000 Oe at 10 K and 450 Oe at 300 K, convenient for various applications.