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Trivalent Al3+-doped samples of magnetite (Alx ${\mathrm {Fe}}_{3-x}\text{O}$ 4, $0.01\le x \le1.0$) were produced by wet chemical method. The X-ray diffraction studies confirmed the formation of a single-phase inverse spinel-type structure. Particles having spherical morphology and size range lying between 4 and 25 nm were observed during transmission electron microscopic investigation. Magnetic measurement displayed increase in saturation magnetization with a maximum value of ~62 $\text{A}\cdot \text{m}$ 2/kg for $x =0.1$ , and thereafter, it started decreasing with increased concentration of Al. The temperature during magnetic hyperthermia got stabilized near therapeutic range (~315 K) for the samples such as $x =0.01$ , 0.5, 0.7, and 1.0 at various external alternating current magnetic fields. [ABSTRACT FROM AUTHOR]

The single phase HfxCe1−xO2 (x = 0.01, 0.05 and 0.1) nanoparticles were produced via microwave refluxing technique. The substitution of Hf-ions into CeO2 lattice has been demonstrated by X-ray diffraction and transmission electron microscopy analyses. X-ray photoelectron spectroscopy analysis indicated that Ce was present in + 3 and + 4 states whereas Hf in + 4 state. Raman, UV-Vis and photoluminescence spectroscopic analyses revealed the formation of surface defects including oxygen vacancies in the samples. The estimated defect concentration was 1.09 × 1021, 1.32 × 1021 and 1.49 × 1021 cm−3 for x = 0.01, 0.05 and 0.1 samples respectively. The room temperature ferromagnetic behavior for the samples originate from the surface oxygen vacancies. The prevalence of ferromagnetic clusters considerably raised the MS value for x = 0.05 sample. The augmentation in the MS values with increased Hf concentration could be attributed to the increase in the defect concentration. [ABSTRACT FROM AUTHOR]

Assuming plane strain conditions and taking phase transformations into account, finite element analysis was carried out using a bead-by-bead deposition model as well as two different lumped models. The effects of post-weld heat treatment at 600 °C were also studied. Predicted residual stresses were verified using X-ray diffraction method. While both bead-by-bead and lumped models were found to overestimate the maximum residual stress in as-welded condition, the latter facilitated a safer upper-bound estimate of the residual stress. The net tensile stress in the weld metal was found to decrease as a result of solid-state transformation of austenite to ferrite. Further, a significant part of stress relief was found to occur in the first half hour of the holding time during post-weld heat treatment. A formula was developed for estimating the maximum residual stress in post-weld heat treated condition. [ABSTRACT FROM AUTHOR]

Alloys of Fe-Si-B with varying compositions of Mn were prepared using high energy planetary ball mill for maximum duration of 120 h. X-ray diffraction (XRD) analysis suggests that Si gets mostly dissolved into Fe after 80 h of milling for all compositions. The residual Si was found to form an intermetallic FeSi. The dissolution was further confirmed from the field emission scanning electron microscopy/energy dispersive X-ray analysis (FE-SEM/EDX). With increased milling time, the lattice parameter and lattice strain are found to increase. However, the crystallite size decreases from micrometer (75-95 μm) to nanometer (10-20 nm). Mössbauer spectra analysis suggests the presence of essentially ferromagnetic phases with small percentage of super paramagnetic phase in the system. The saturation magnetization ( M), remanance ( M) and coercivity ( H) values for Fe-0Mn sample after 120 h of milling were 96.4 Am/kg, 11.5 Am/kg and 12.42 k Am, respectively. However, for Fe-10Mn-5Cu sample the M, H and M values were found to be 101.9 Am/kg, 10.98 kA/m and 12.4 Am/kg, respectively. The higher value of magnetization could be attributed to the favourable coupling between Mn and Cu. [ABSTRACT FROM AUTHOR]

In the present study, lead-free piezoelectric (1-x)[(Bi 0.96 La 0.04 ) 0.5 Na 0.5 TiO 3 ]-(x)[Ba 0.90 Ca 0.10 TiO 3 ] ceramics with x ≤ 0.20 have been prepared at optimum temperature (950°C–1050 °C) by employing semi-wet technique. The effect of Ba 0.90 Ca 0.10 TiO 3 (BCT) content on the phase formation, surface morphology, dielectric and piezoelectric properties is systematically investigated and characterized by X-ray diffraction (XRD), Raman Spectroscopy, Field emission Scanning electron micrographs (FE-SEM), Impedance analyzer. XRD analysis shows phase transformation from rhombhohedral to tetragonal with the addition of BCT and the average grain size decreases with BCT content, x. Temperature dependent dielectric behavior exhibits two phase transitions, i.e. depolarization temperature; T d and phase transition temperature; T m . The phase transitions; T m tends to diffuse with increasing x and exhibited a broad frequency dependent maximum upto x ≤ 12. Optimum piezoelectric and dielectric properties (i.e., d 33 = 165 pC/N, k p = 39%, k t = 47% and k 33 = 57%, ε r = 1585, tan δ = 0.07) in the studied system have been obtained. [ABSTRACT FROM AUTHOR]