Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5490236 | Journal of Magnetism and Magnetic Materials | 2017 | 8 Pages |
Abstract
We have built a scanning dc-susceptometer for magnetic characterization of millimeter-scale samples. Using samples with few millimeter-thick slabs, the setup used is able to apply perpendicularly to the sample uniform dc magnetic fields up to 500 mT. It has a scanning range of 100 mm Ã 100 mm with micrometer resolution. In the present configuration, the dc-susceptometer is equipped with a pair of commercial Hall effect sensors forming an axial gradiometer. The measured output noise at 6.0 Hz is about 1.0 µTrms/âHz in an unshielded environment and the magnetic moment sensitivity is 8.8 Ã 10â11 Am2. In particular, we used it to characterize heat-resistant steels, used as radiant tubes in steam reformer furnaces. We measured the cross-section of tube samples with progressing states of aging from as-cast to state VI. Measuring their susceptibilities, we detected a ferromagnetic layer at the external tube wall on aged samples. We were able to establish a relation between the magnetic response and the microstructural change of the steel.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
João M.B. Pereira, Clara Johanna Pacheco, Monica P. Arenas, Jefferson F.D.F. Araujo, Gabriela R. Pereira, Antonio C. Bruno,