Microwave Absorption Study of Nano Synthesized Strontium Ferrite Particles in X Band
Microwave ferrites require high coercivity for their use as microwave absorbers. Strontium hexaferrite is one of the best material due to its magnetic properties , high coercivity, large unilateral magnetic anisotropy and very low cost in comparison to others make it suitable for the use as microwave components specifically microwave absorber .Strontium nano hexa ferrites were successfully synthesized through chemical co-precipitation method. The synthesized nanostructure was characterized by X-Ray powder diffraction(XRD) and fourier transform infrared spectroscopy (FTIR).The XRD result shows the shift from amorphous to crystalline after the calcination of sample at 600 0 C.The behaviour of ferrite as microwave absorber was also studied for X band of frequencies.
Dependence of pH Variation on the Structural, Morphological, and Magnetic Properties of Sol-Gel Synthesized Strontium Ferrite Nanoparticles
In this research work, an attempt of regulating the pH as a sol-gel modification parameter during preparation of SrFe 12 O 19 nanoparticles sintered at a low sintering temperature of 900 (cid:1) C has been presented. The relationship of varying pH (pH 1 – 14) on structural microstructures and magnetic behaviors of SrFe 12 O 19 nanoparticles was characterized by X-ray diffraction (XRD), field emission scanning microscope (FESEM), thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR), and vibrating-sample magnetometer (VSM). The single-phase SrFe 2 O 19 with optimum magnetic properties can be obtained at pH 1 with a sintering temperature of 900 (cid:1) C. As pH values increase, the presence of impurity Fe 2 O 3 was observed. TGA data-varying pH shows that the total weight loss of most samples was at 30.44% which corresponds to the decomposition process. The IR spectra showed three main absorption bands in the range of 400 – 600 cm (cid:3) 1 corresponding to strontium hexaferrite. SEM micrographs exhibit a circular crystal type of strontium ferrite with an average crystal size in the range of 53 – 133 nm. A higher saturation magnetization M s , remanent magnetization M r , and hysteresis H c were recorded to have a large loop of 55.094 emu/g, 33.995 emu/g, and 5357.6 Oe, respectively, at pH 11, which make the synthesized materials useful for high-density recording media and permanent magnets.
Chromatographic analysis of elastomer antidegradants and accelerators
Summary The use of various chromatographic methods in the analysis of all classes of elastomer antidegradants and accelerators is reviewed. The review of extraction methods is also included.