## 1 Introduction  
The number of electrical devices used in industry and households is increasing year by year, which causes a continuous increase in the demand for electrical energy [1]. Although the way electricity is produced is undergoing continuous transformation, a large part of it is still produced using fossil fuels, so an increase in energy demand may result in an increase in CO\({}_{2}\) emission, which, in turn, requires the introduction of regulations. Reducing the carbon footprint can be achieved in various ways, such as by producing and using renewable energy, modernizing technology, or investing in CO\({}_{2}\) capture and storage infrastructure [2]. Despite the above-mentioned propositions which usually require additional funding, it is possible to reduce energy consumption by the development and manufacturing of more-energy-efficient devices which will result in a cost and carbon footprint reduction. Not only are the end devices important, but each stage of energy production and transmission should be characterized by low energy losses; hence, the huge interest in increasing the energy efficiency of distribution transformers has been observed for years. The main part of the transformer is a ferromagnetic core [3,4]. The first material used for transformer cores was shaped iron, but, over time, isotropic hot-rolled steel, then anisotropic cold-rolled grain-oriented steel, and then high-permeability steel came into use. In later stages, domain-refined steel, microcrystalline steel, nanocrystalline steel, and, finally, amorphous steel were used [5,6]. Amorphous steel, called also metallic glass, is an amorphous metal characterized by the fact that its atoms do not have a long-range order. It is received from melted alloy through solidifying with very rapid cooling, \(10^{6}\) K/s [7,8]. The final shape of the material is a thin--for example, \(25\)\(\upmu\)m--ribbon, which possess outstanding magnetic properties like a high magnetic permeability and easy magnetization [9,10]. Easier magnetization is the solution for problems observed during core development, mainly hysteresis losses. Using amorphous steel for core production also allows for a reduction in the eddy current losses, as this material exhibits high resistivity [11,12]. This kind of loss is strongly related to the thickness of the magnetic material [8]; therefore, using a very thin amorphous ribbon strengthens this positive effect. Taking into account the above benefits, the total amorphous core losses are 70% lower in relation to the core made of regular grain-oriented steel [13]. Despite such great progress, there are still some drawbacks when using an amorphous metal ribbon for the transformer core production. The disadvantage of the amorphous metal ribbon is that it is very thin, easily deformed, and, thus, prone to the magnetostriction effect. In the presence of the magnetic field, the magnetic material changes its dimensions and, as a result, starts to deform. A direct consequence of the frequent deformation of amorphous laminates is an audible sound, which is 3-5 dB higher for the core made of amorphous steel, in relation to the transformer core made of the grain-oriented steel [13]. During the fabrication of the amorphous steel, rapid cooling is mandatory, but this results in quenching stresses. Such stresses can be reduced by annealing at an elevated temperature [14,15], which is also used for the magnetization process. Unfortunately, annealing turns the amorphous material into a brittle form, which makes it more complicated for further processing. The application of the binder between laminates is a solution for both the aforementioned problems [16] as it leads to core solidification. Topics related to core solidification and, thus, strengthening it are known; however, they are presented mostly in patents, and research data in scientific papers are limited. The problem with the transportation of the annealed amorphous core can be solved by applying a ceramic coating [17] or resin [18] on the edge of the core.