عنوان
پدید آورنده
موضوع
رده
کتابخانه
محل استقرار
TLpq2323919310
انگلیسی
Characterization of Heat-Treated and Laser-Treated Nano-Crystalline Soft Magnetic Alloys
[Thesis]
Anwar, Bhuiyan Muhammad Muktashif
The University of Toledo
2019
113
M.S.
The University of Toledo
2019
Fe77Co5.5Ni5.5Zr7B4Cu1 can be prepared as a soft magnetic alloy consisting of nanoscale crystallites that are smaller than the magnetic domains. The crystallite sizes are small enough to alleviate energy loss associated with the magnetocrystalline anisotropy, which decreases the coercivity and makes the material suitable for high-frequency applications. The nanoscale grain sizes can further affect the magnetizing and demagnetizing properties of the material, leading to superparamagnetism and improved high-temperature performance. While there are other alloys in this class that have shown potential for high-frequency and high-temperature applications, this specific alloy was chosen because of its optimal magnetic properties in its ribbon form and because of an existing collaboration with a research group at Case Western Reserve University (CWRU), lead by Dr.Willard, which has expertise in the fabrication of such materials. This project focuses on two forms of the alloy, the thin film form and the ribbon form. The ribbon form of the alloy was provided by CWRU and was characterized both in the original as-spun state and after various heat treatment steps. The thin films were deposited from a bulk piece of the alloy. This material was machined down to a proper disk which was 2 inches in diameter and 0.06 inches thick and used as a sputtering target to deposit the films onto silicon wafer substrates. A radio-frequency (RF) sputtering method was used for the deposition process and the films were deposited at a range of substrate temperatures. Some of the films deposited at room temperature were then annealed at various temperatures. Structural and magnetic property characterization was performed on all types the samples. Another part of this thesis research consisted of an analysis of the effects of a laser treatment process on the ribbons of the alloys and post-treatment characterization of ribbons and thin film samples, deposited at room temperature. The laser processing consisted of pulsed laser irradiation done at different fluences and in a nitrogen atmosphere. Structural phase changes were followed as a function of the laser fluence. The magnetic properties were then measured with the help of our collaborators at CWRU. Correlations between magnetic, structural and electrical properties of both ribbon and thin film samples, on one hand, and grain size estimates from X-ray diffraction pattern analysis and surface roughness measurements, on the other hand, were examined.
Electrical engineering
Nanotechnology
Anwar, Bhuiyan Muhammad Muktashif
مطالعه متن کتاب p
[Thesis]
276903
a
Y
