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Influence of different sub-core materials on inductance in annealed passive magnetic components / Mohd Haris Murshidi Mohd Mdzuki

By:

Mohd Haris Murshidi Mohd Mdzuki [author.]

Material type: Text

text

Media type:

unmediated

Carrier type:

volume

ISBN:

THE0009499 (Local)

Subject(s):

Dissertation note: Thesis (Master of Science) -- Universiti Malaysia Pahang – 2026 Abstract: Passive magnetic components are known for their excellent magnetic permeability, low coercivity, and also high saturation flux density, is the foundation of various medium- and high-frequency technologies. It can be found on transformers, motors, generators, and also magnetic sensors. Among these, Fe-ribbon core is known as a key material in the production of inductive components. The magnetic properties of Fe-ribbon core are influenced by the magnetic field annealing process. The induced anisotropies and the softening can alter performance outcomes significantly. In addition, the presence of adjacent materials sub-cores—during annealing may affect the final inductance value of the cores. Up to the present, the influence of neighbouring materials on the final inductance of an Fe-ribbon core has not been thoroughly investigated. Observations from past magnetic test data revealed a recurring issue: A significant drop in inductance at 10 kHz for bottommost cores tested after magnetic annealing process. This drop not only leads to higher rejection rates but also reduced the production yield. Despite its impact on product quality, no research has been conducted to find out the root cause of this low inductance values on bottommost core compared with other Fe-ribbon core on the same annealing needle. Therefore, this study aims to investigate the influence of various sub-core materials and configurations on the magnetic performance of annealed Fe-ribbon cores, with a main focus to improve the consistency in inductance values in mass-production environment. The objectives of this research are twofold: (1) To investigate the influence of sub-core materials on the inductance value of annealed Fe-ribbon core, and (2) to analyse the relationship between hysteresis loss and inductance values of annealed Fe-ribbon core. Fe-ribbon core composed of Fe-Cu-Nb-B-Si alloy was used as the substrate material, while mild steel (ST37), alloy steel (AISI4140), stainless steel (SUS304) and ceramic (Al2O3) was used as the sub-cores. Magnetic annealing process was carried out using a furnace with a high holding temperature. The magnetic properties and hysteresis loops of the annealed cores were measured using a dedicated electrical/magnetic tester, UNITESTER. The areas under the loop computed using coordinate extraction software, WebPlotDigitizer and Gauss’s area formula. The observed variations in inductance deviation of bottommost Fe-ribbon core among different sub-core materials indicate that the deviation is primarily governed by the selected sub-core. Mild steel, which, classified as a ferromagnetic, showed the lowest deviation (10 %), followed by stainless steel which is paramagnetic (25 %) and ceramic that belong to diamagnetic (48 %). The results also indicated that hysteresis loss of the Fe-ribbon cores exhibits a non-linear relationship with inductance value. In addition, incorporating a weight support structure reduced mechanical stress on the core, leading to an increase in overall inductance value from 47.1 μH to 52.3 μH and a reduction in inductance deviation of bottommost Fe-ribbon core from 12.8 % to 12.6 %. Overall, the combination of a high-permeability sub-core material and a low-stress mechanical configuration minimized hysteresis loss while enhancing magnetic consistency in production of mass Fe-ribbon core.

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Holdings ( 2 )
Title notes ( 4 )

Holdings
Item type	Current library	Collection	Call number	Copy number	Status	Date due	Barcode
Restricted Collection	UMPLIB PEKAN	Non-fiction	FTKPM .H37 2026 r Thesis (Browse shelf(Opens below))	1	Final Processing		T000005618
Restricted Collection	UMPLIB PEKAN	Non-fiction	CD14048 (Browse shelf(Opens below))	1	Final Processing		T000005619

Faculty of Manufacturing and Mechatronic Engineering Technology

Thesis (Master of Science) -- Universiti Malaysia Pahang – 2026

Includes bibliographical references

Passive magnetic components are known for their excellent magnetic permeability, low coercivity, and also high saturation flux density, is the foundation of various medium- and high-frequency technologies. It can be found on transformers, motors, generators, and also magnetic sensors. Among these, Fe-ribbon core is known as a key material in the production of inductive components. The magnetic properties of Fe-ribbon core are influenced by the magnetic field annealing process. The induced anisotropies and the softening can alter performance outcomes significantly. In addition, the presence of adjacent materials sub-cores—during annealing may affect the final inductance value of the cores. Up to the present, the influence of neighbouring materials on the final inductance of an Fe-ribbon core has not been thoroughly investigated. Observations from past magnetic test data revealed a recurring issue: A significant drop in inductance at 10 kHz for bottommost cores tested after magnetic annealing process. This drop not only leads to higher rejection rates but also reduced the production yield. Despite its impact on product quality, no research has been conducted to find out the root cause of this low inductance values on bottommost core compared with other Fe-ribbon core on the same annealing needle. Therefore, this study aims to investigate the influence of various sub-core materials and configurations on the magnetic performance of annealed Fe-ribbon cores, with a main focus to improve the consistency in inductance values in mass-production environment. The objectives of this research are twofold: (1) To investigate the influence of sub-core materials on the inductance value of annealed Fe-ribbon core, and (2) to analyse the relationship between hysteresis loss and inductance values of annealed Fe-ribbon core. Fe-ribbon core composed of Fe-Cu-Nb-B-Si alloy was used as the substrate material, while mild steel (ST37), alloy steel (AISI4140), stainless steel (SUS304) and ceramic (Al2O3) was used as the sub-cores. Magnetic annealing process was carried out using a furnace with a high holding temperature. The magnetic properties and hysteresis loops of the annealed cores were measured using a dedicated electrical/magnetic tester, UNITESTER. The areas under the loop computed using coordinate extraction software, WebPlotDigitizer and Gauss’s area formula. The observed variations in inductance deviation of bottommost Fe-ribbon core among different sub-core materials indicate that the deviation is primarily governed by the selected sub-core. Mild steel, which, classified as a ferromagnetic, showed the lowest deviation (10 %), followed by stainless steel which is paramagnetic (25 %) and ceramic that belong to diamagnetic (48 %). The results also indicated that hysteresis loss of the Fe-ribbon cores exhibits a non-linear relationship with inductance value. In addition, incorporating a weight support structure reduced mechanical stress on the core, leading to an increase in overall inductance value from 47.1 μH to 52.3 μH and a reduction in inductance deviation of bottommost Fe-ribbon core from 12.8 % to 12.6 %. Overall, the combination of a high-permeability sub-core material and a low-stress mechanical configuration minimized hysteresis loss while enhancing magnetic consistency in production of mass Fe-ribbon core.