Electromagnetic radiation can have a negative effect on electronic circuits, for example, by disrupting their work and communication. Therefore, there is a need to reduce or eliminate electromagnetic interference using shields. This paper focuses on using waste materials in the form of iron scale, which is easy and inexpensive to obtain for shielding. Iron scale is the result of gaseous or aqueous corrosion, due to which a superficial layer of metal oxides formed on the surface of heated metal objects as a result of their contact with air or water during an industrial process is developed. In this study, morphology, chemical, and phase composition measurements were carried out. The results show that all the iron-based materials investigated are mainly composed of iron oxides and pure iron. The polymer–iron composites with different quantitative and qualitative compositions were prepared to verify the shielding effectiveness. The electrical resistance, impact strength, and magnetic properties were measured, and dynamic mechanical thermal analysis and tensile strength tests were performed. The tests confirmed the suitability of iron scale for the construction of electromagnetic field shielding material. Iron scale is cheap and easy to obtain from iron-based waste materials. The developed composites are easy to form and use recycled material.
This article presents a method for detecting defects and assessing their size in soft magnetic composites (SMCs) based on magnetograms obtained from a magnetic field camera and a numerical analysis of the magnetic field around them. For the purpose of the experiment, toroidal samples of a metal–polymer composite were made, in which holes and gaps simulating defects were prepared. The magnetic camera allowed for registering the magnetic flux density image near the surface of the samples. As a result, magnetograms with information about the location and geometry of defects were obtained. A numerical analysis was used to investigate the influence of various factors, such as defect depth, its size and material permeability. Theoretical changes in magnetic field over defects stay in good agreement with measurements, which is a strong indication that surface field magnetograms can be useful in a quality assessment of the considered composites. The effectiveness and usefulness of the method in detecting surface and shallow subsurface defects in SMC materials was confirmed. The influence of a possible tangent component of the exciting field was demonstrated and discussed.
The development of technology in the field of new textronic materials allows for their wider application in everyday use. Hence the authors' interest in the use of textiles with an electroconductive coating as screens of non-ionizing electromagnetic fields. Thanks to the use of textronic materials, it is possible to obtain a flexible cover with appropriate strength, elasticity and, above all, the required functionality, which is the elimination of undesirable interference and electromagnetic radiation. The work examined material properties of samples, shielding effectiveness and measurements of volume and surface resistance.
Streszczenie Magnetic non-destructive testing are very useful in assessing the quality of metal-polymer composites. In order to quickly determine homogeneity, occurrence of inclusions, cracks and other defects, the inspection method using a magnetic field camera was proposed. For the verification of the method, samples containing various types of inclusions (polymer and steel) and reference samples were prepared. The tests were carried out using a neodymium magnet as the source of an external magnetic field. The flux density of the field was mapped just above the sample surface using a 3D camera. The obtained magnetograms allowed to locate and identify the type of inclusions. This confirmed the effectiveness of the developed method.
The paper presents an analysis of the possibility of producing traction brushes from waste materials. Brushes are used to ensure good electrical contact between the rail and the pantograph. Slides are produced in the process of hot pressing, with parameters of heating up to max 175 ⁰C, at the minimal pressure value of 200 MPa. The developed brushes with a high (55-60%) content of recycled materials have comparable characteristics to commercial brushes, and some of the prototypes are even more durable and break-resistant.
Modern industry is looking for new functional materials with the same or better functional properties while reducing the burden on the natural environment. A group of innovative materials such as composites, which are a combination of components with different and complementary properties and the appropriate technology of their production meets these expectations. The preliminary studies carried out indicate the possibility of using a developed method of producing a metal / polymer composite for the construction panels and casings covering the electromagnetic field.