Intensive Improvement of Cementite Synthesis

Cementite extraordinary mechanical properties have drawn the attention of researchers in recent years. But, the limited methods for the production of this material, led to the production of iron with more than 2.1%wt carbon content beside free carbon by simultaneous thermal-mechanical activation of hematite and graphite mixture at 800°C for 6 hours in the present research. Then, a structure with more than 80%wt cementite was obtained through partial melting process at 1180°C for 25 minutes.

S-type granites in the western Superior Province: a marker of Archean collision zones

Detailed field observations indicate that Neoarchean S-type granites were emplaced along and (or) proximal to some terrane (tectonic) boundary zones in the western Superior Province, southeastern Manitoba. These S-type granites are characterized by the presence of at least one diagnostic indicator mineral, such as sillimanite, cordierite, muscovite, garnet, and tourmaline. They are medium- to high-K calc-alkaline, moderately to strongly peraluminous (ANKC >1.1), and contain >1% CIPW normative corundum. Compared with more voluminous, older I-type granitoids in tonalite–trondhjemite–granodiorite suites in the region, the S-type granites occur as relatively small intrusions and have high (SiO2 >72 wt.%) contents with a small silica range (SiO2 = 72.2–81.2 wt.%), but a large range of Zr/Hf (17.1–43.8) and Nb/Ta (0.3–16.0) ratios. These geochemical characteristics suggest that the S-type granites were derived from partial melting of heterogeneous sedimentary rocks deposited as synorogenic flysch that underwent burial and crustal thickening during terrane collision. Although the S-type granites display geochemical variations in individual and between different plutons, their low Sr (<400 ppm) and Yb (<2 ppm) contents and low Sr/Y (<40) and La/Yb (<20) ratios are consistent with a partial melting process that left a granulite-facies residue consisting of plagioclase, pyroxene, and ± garnet. The S-type granites display low zircon saturation temperatures (mostly <800 °C) and low emplacement pressures (<300 MPa), similar to strongly peraluminous leucogranites formed in the Himalayas. Therefore, we propose that the Neoarchean S-type granites in the western Superior Province, whose source rocks were deposited between colliding tectonic blocks between 2720 and 2680 Ma, may serve as a geological marker of some Archean terrane boundary zones.

Critical Current Density and Pinning Energy of Partial Melted Sm-Based Superconductor

The relationship between critical current density (Jc) and pinning energy (Up) in partial melted superconductors was investigated. The partial melted Sm-Ba-Cu-O superconducting bulks were composed of SmBa2Cu3Ox (Sm-123) superconductor and Sm2BaCuOy (Sm-211) insulator. The pinning force and the pinning energy of the superconductor were measured by a system combining an electronic balance and permanent magnet. The pinning energy and the Jc of the samples were influenced by crystalline orientation. The Jc of the samples depends on the pinning energy. However, in the partial melting process, changes in retention temperature altered the Jc values but had little effect on the value of the pinning energy. The results indicated that Jc was influenced by the dispersion of the insulator acting as a pinning center with in the superconducting bulks.