Thermomagnetic Analysis of the Crystallization in Soft Magnetic Nanocrystalline Alloys

In this work, we investigated the dynamics of nanocrystallization from the amorphous state of the Fe72.5Cu1Nb2Mo1.5Si14B9 alloy together with magnetic phase transformations. The thermomagnetic analysis was performed with the simultaneous recording of the temperature inside the core by a thermocouple and the inductance of the winding wound over the core. It was found that the permeability of the core after the crystallization peak first increases rapidly, and then decreases and stabilizes at some level. Permeability growth begins at a temperature that coincides with the Curie point of the Fe80Si20 solid solution. A decrease in permeability was associated with stabilization of the structure of the amorphous and crystalline phases upon cooling. With decreasing temperature, the active redistribution of chemical elements is suppressed, and silicon atoms occupy a stable position in the crystal lattice of iron. Nanocrystalline cores have different Curie temperatures in the state after the peak of crystallization and 300 seconds after the peak. This indicates the continuation of the diffusion of silicon from the amorphous matrix into Fe-Si nanocrystals for some time after the crystallization peak.

The history and state-of-the-art of the studies of native iron in terrestrial and extraterrestrial rocks

A brief review on the history of studying native iron in terrestrial rocks and meteorites is presented. The synthesis and systematization of extensive data on the distribution, composition, and grain size of metal iron particles in sediments, other terrestrial rocks, and meteorites obtained by thermomagnetic analysis with heating to 800 °C combined with microprobe analysis are described. The studies show that ironparticles in all the studied sediments typically have extraterrestrial origin. Based on the statistical analysis of the thermomagnetic data, a number of indications (statistical regularities) are proposed testifying to the overwhelmingly extraterrestrial origin of iron particles in sediments. The similarity of the formation conditions of terrestrial and extraterrestrial metal iron particles makes it possible to suggest a petromagnetic scheme for the structure of planets based on the distribution of metal iron in them.

Thermomagnetic Analysis of the Lake Matano Sediments and the Surrounding Lateritic Soils, South Sulawesi, Indonesia

Thermomagnetic is one of the most commonly used measurements for determining the dominant type of magnetic mineral of samples. The measurement is separated into two distinct processes, heating and cooling. The sample susceptibility is measured for each temperature change, i.e., from room temperature to 700oC and vice-versa. Based on the thermomagnetic measurement results, magnetite is found to be the predominant magnetic minerals in Lake Matano sediments. The present study applied a correlation analysis technique on the results of thermomagnetic measurement of Lake Matano sediments and compared the result to that of lateritic soils to indicate whether a diagenetic process has occurred on the lake sediments.

Technogenic magnetic particles of topsoil from different sources of emission - A case study from upper silesian conurbation, Poland

Studies on the effects of dust deposition on soils in urban-industrial areas were conducted with application of magnetic (soil magnetometry, thermomagnetic analysis) and geochemical (elements content) methods. The study area covers three different forest sites on Upper Silesian Conurbation. The purpose of the research was an estimation of soil pollution and characteristic of air derived particles. Results show magnetite and maghemite as dominant magnetic components of analyzed soil samples. The highest volume magnetic susceptibility (κ) and no correlation with potentially toxic elements (PTEs) were stated close to metallurgical plant whilst the highest correlation coefficient between κ and PTEs was stated in samples from the urban area and in a vicinity of coking plant.

Magnetic phase diagrams of Gd-H, Tb-H, Dy-H systems

We study the impact of hydrogen impurity on the magnetic phase transition temperatures of the high purity rare-earth metals Gd, Tb and Dy. Prior to hydrogenation, the rare earths were purified by the vacuum distillation method. Hydrogenation was carried out using a Sievert-type apparatus. Magnetic phase diagrams were constructed based on the thermomagnetic analysis.