## 1 Introduction  
The article describes a method of depositing a thin film of special anti corrosive material on the inner surface of slim tubes in sufficient quantity to guarantee anti corrosive protection. The trade name of the substance applied is \"Anticorid DFT 2001\" (hereinafter \"oil\") from Fuchs Oil Corp. Ltd. (Gliwice, Poland) [1]. The main reason for this solution was to protect non-resistant steel pipes from atmospheric corrosion. However, the knowledge referred to in this article may also be applied to other purposes and to materials other than non-refractory steel from which the tubes in question are made. According to [PERSON] [2] and also [PERSON] et al. [3], simple procedures and guidelines for protection can be found in the use of corrosion inhibitors, which represent an inexpensive and effective alternative to traditional protections, Cathodic protection, incorporation of suitable alloys, efficient process control, reduction of alloy impurities and use of surface treatment techniques, etc. In their introduction of the principle procedure, [PERSON] and [PERSON] [4] take the matter a step further, describing nanoparticles of oil deposited by dispersion as a corrosion protective layer. According to the authors, standard methods have already been applied, such as electrochemical impedance spectroscopy and potentiodynamic polarization to determine the corrosion resistance performance. Still other feasible methods for achieving sufficient corrosion protection are available in the articles by [PERSON] et al. [5] and also by [PERSON] et al. [6]. If it is necessary to improve the carbon steel surface corrosion resistance and also its resistance to mechanical wear, then it is appropriate to choose a method of compact, dense layer deposited on the surface by means of thermal spraying. [PERSON] et al. [7] wrote that these methods of coating the surface with ceramic composite materials should be considered and combined with methods such as open-circuit potential measurement (OCP) and electrochemical impedance microscopy (EIS). The tribological and mechanical properties are also investigated using a tribometer (pin-on-disk). A departure from these practices is necessary where mechanical and chemical resistance is to be combined. Here, [PERSON] and [PERSON] [8] discuss the so-called FBE (Fusion bonded epoxy) powders and liquid resins, commonly used for corrosion protection of steel pipes and metals. However, this protection accounts for increased mechanical stress and is also more demanding in terms of application. When investigating steel pipes with non-destructive evaluation methods (NDE), whether for integrity of these pipes or for the purpose of their monitoring, the oil layer often poses a problem. For this reason, [PERSON] recommends [9] the use of specially developed modern methods for oiled pipes to meet the objectives, such as a pulsed eddy current (PEC). Another aspect of the issue, namely the phenomena of droplet impact on droplets, along with secondary droplets, is explored by [PERSON] et al. [10]. Their numerical study presents the morphology and droplet dynamics. The authors conclude by pointing to the overall complexity of the issues studied. The impact of droplets is closely related to boundary conditions such as wall temperature, droplet temperature, impact velocity, viscosity, wall spray distance, wall moisture, and injection pressure. The authors propose an improved model of the assumed splashing structure that takes into account the corona splashing fluid and its sudden impact. They also focus on high temperature increase that is used in combustion engines, an approach quite different from ours. Closer examination of the impact of a droplet on a flat stainless steel surface of varying roughness offers [PERSON] et al. [11]. Their study uses an experimental method of high-speed microphotography. The processed results show that the incident droplet extends on the surface in the form of a marginally bounded lamella. However, for other fluids and fuel oil (diesel), behavioral dynamics differ.