## 1 Introduction
It is also possible to find patents where the resin was applied directly on the amorphous ribbon, aiming to receive a substrate covered with insulation material [19,20]. Finally, there are two patents which present solutions on how to reduce the audible noise of the working magnetic core. One of them describes the application of a dielectric, high-strength tape on the columns [21], while, in the second one, an organometallic binder was applied [16]. In both cases, the applied solutions results in a reduction in the audible noise of the amorphous magnetic core. It is worth mentioning the authors' previous scientific paper, in which the binder was applied directly on the amorphous metal ribbon, and then the magnetic core was formed [22]. In that work, we presented polyimide as a binder for the amorphous metal ribbon, and, in the first step, the quality of the applied layer was confirmed with Confocal Microscopy and Scanning Electron Microscopy. Moreover, stable dielectric values, an anticorrosive character, and good binding properties were confirmed. The last paragraphs of the paper [22] describe magnetic and acoustic properties, and the most important conclusion was that the applied solution resulted in a lowering of not only audible noise, but also magnetic losses. It was highlighted in [22] that a proper binder should be characterized with a good wettability of the amorphous metal and should create a solid bond with the substrate. At the same time, it cannot cause--and it is even expected to prevent--the degradation of the metallic surface by the corrosion process. The applied layer needs to be dielectric and be of good quality, free of cracks. In order to avoid cracks, it is worth considering the value of the coefficient of thermal expansion (CTE), which should be similar to the substrate, as we highlighted in the authors' other work [23]. A mismatched binder can cause additional stress and, as a result, increases the core losses and exciting current. It can then be observed as a more noticeable magnetostriction effect and amplified noise [21]. Considering the above requirements, we proposed a second type of the hybrid binder for the amorphous metal ribbon based on alkoxysilanes, namely, on tetraethoxysilane (TEOS) and 1,2-bis(triethoxysil)ethane (BTSE) [23]. The TEOS and BTSE layers were deposited in a stepwise way, TEOS directly on the metallic glass ribbon, with the BTSE layer on the top. Adequate TEOS properties are confirmed in the literature, like chemical and thermal stability [24], a good dielectric constant [25], and a low CTE [26]. Moreover, it has been proven that TEOS-based silica layers improve the corrosion resistance of various metallic substrates, like aluminum, steel, copper, and magnesium [27; 28; 29; 30]. Despite good overall properties, layers based on TEOS are rather rigid; therefore, the second type of the silane was used, namely, BTSE, in order to create a layered hybrid structure. [PERSON] et al. [26] explained that BTSE possesses higher rotational freedom and more empty volume in the final layer. Consequently, the BTSE layer is more flexible. The same as TEOS-based layers, BTSE films protect metallic surfaces from corrosion [31; 32]. The suitability of sequential deposition, where the first deposited layer is TEOS and the second is BTSE, has been confirmed in our other paper [33]. The results of the spectroscopic and rheological measurements provide information that the TEOS sol reacts faster than BTSE. A faster hydrolysis of TEOS leads to a high number of reactive hydroxyl groups, ready to couple with a metallic surface and with hydrolyzed BTSE. The objective of the work presented here is to complete our previous scientific work [23], in which it was confirmed that the TEOS-BTSE hybrid layer deposited on the amorphous metal ribbon is continuous and crack-free. Furthermore, it was observed that the CTE of the first TEOS-based layer is similar to that of the metallic glass substrate, suggesting that it should not induce additional mechanical stress.