Rapid Characterization Method for SMC Materials for a Preliminary Selection

Abstract

In electrical machines, laminated steels are commonly adopted as soft magnetic materials, while for permanent magnets, sintered ferrites and NdFeB are the most common solutions. On the other hand, the growing demand for volume reduction with the increment of efficiency leads to the necessity of exploring other magnetic materials able to face the challenge better than the traditional ones. Bonded magnets have been used to replace sintered magnets, obtaining a better use of space and particular magnetic properties. Instead, for the magnetic circuit, Soft Magnetic Composites (SMC) allow realizing very complex magnetic design (3D path for flux) with iron loss reduction at medium-high frequencies, especially for the eddy currents loss contribution. On the other hand, SMC materials have such drawbacks as low mechanical properties and high hysteresis losses. For this reason, in this work, different studies considering several variables have been carried out. SMCs were produced through a moulding process; inorganic and organic layers to cover ferromagnetic particles were used, adopting different coating processes. Particular tests have been performed for a quicker and more indicative overview of the materials obtained. The single sheet tester (SST) is easier than traditional toroidal methods; on the other hand, the multiplicity of variables affects the SMC materials and their process. For this reason, coercivity and conductibility tests permit rapid measurement and provide a direct classification of the produced SMCs, providing the main information needed to select suitable materials. Results highlighted that choosing the more appropriate SMC material is possible after using these simple preliminary tests. After these tests, it was possible to argue that with 0.2 wt% of phenolic resin as the organic layer (and compaction pressure of 800 MPa), it is possible to produce a good SMC. On the other hand, the SMC with 0.2 wt% of epoxy resin (and compaction pressure of 800 MPa) gives a minor coercivity value. Additionally, despite the SMC with the inorganic layer, 0.2 wt% of nano-ferrites showing the best coercivity values (specifically for vacuum treatment at 600 °C), their resistivity was unsatisfactory.

Manufacturing of Pure Iron by Cold Rolling and Investigation for Application in Magnetic Flux Shielding

“…Electromagnetic shielding for low-frequency applications can be achieved by using high permeable flux shunting material. On the other hand, in the case of high-frequency applications (above 1 MHz), a combination of flux shunting material along with an electrically conducting layer for eddy currents cancellation is preferred [ 27 , 50 ]. A finite element simulation is performed to estimate the shielding effectiveness with the use of the pure iron material (manufactured in the present study) along with two types of conducting material (aluminum and copper with 1 mm-thick iron and conducting material).…”

“…Magnetometric and inductive methods are used for the characterization of magnetic materials. The magnetometric methods, including vibrating sample magnetometer (VSM) test, are not suitable for the determination of the hysteresis and initial magnetization curves of high permeable materials such as pure iron and electrical steel, due to the demagnetizing effect on the test specimen [ 27 ]. On the other hand, inductive methods as per IEC60404-4 are preferred for the determination of the hysteresis loop and initial magnetization curve of high permeable soft magnetic materials, including that of the pure iron.…”

The Influence of Cutting Technology on Magnetic Properties of Non-Oriented Electrical Steel—Review State of the Art

“…As a result of their use, the destruction the material's internal structure, resulting from the implementation of the mechanical laser cutting process (manifested by the deterioration of the material's magnetic prop ties), is avoided. Referring to additive manufacturing methods, a group of works descr ing research conducted on sintered materials can be identified [8][9][10][11][12][13][14][15], as well as a gro of works depicting the research results using laser powder bed fusion technology As the published research results on SMC and LPBF materials indicate, they can be us mainly in motors operating at frequencies of kHz and higher. Then, the low specific ir loss of the material about the Fe-Si laminates, which the authors of this article deal w Hence, there is a common interest in both the problem of the exact description of core losses and the search for methods to reduce them.…”

Prediction of the Properties of Modified Phenol-Formaldehyde Composites Using Mathematical Modeling of the Composition of the Polymer Mixture

“…The phenolic coating provides long-lasting, high-quality protection against corrosion, scratches, and cracks [1,2]. Heat-treated phenolic coatings can be used in a wide range of acidic environments, even highly acidic environments, as they have excellent acid chemical resistance even at high temperatures [3,4]. Thus, phenolic coatings are optimal for various industrial applications such as fume hoods, pumps, pipes, and tank linings.…”