During the electrospark alloying, the use of the tool-electrodes from Al-Sn alloy makes it possible to manufacture the coatings on aluminum alloys with inclusions of micro-disperse structures (including nanofibers), which consist of the oxides of an easily melted component (tin) [1,2]. These coatings are distinguished by specific properties, namely, while exhibiting low hardness they demonstrate high wear resistance, that exceeds that of the hard steel by 5 ÷ 8 times [2, 3]. However, a long-term exploitation changes significantly the properties of such electrode-tools, which affects the efficiency of the process of the electrospark alloying.  This work is devoted to the investigation into the nature of the changes in their properties. In the study, we used the XRD and EDX analysis data both of the initial electrode-tools (manufactured by a casting method) and electrode-tools after exploitation for different periods of time.   As a result of the works performed it was established that: 1. In the process of the electrospark alloying, oxidation of the elements of the electrode-tool occurs, and as a consequence, the content of oxygen in its composition increases.  2. In the process of the electrospark alloying, the process of interaction between the electrode-tool and the specimen takes place; as a result, the material of the electrode-tool (anode) becomes enriched with the material of the cathode (aluminum alloy D1: zinc, iron, etc.). 3. X-ray phase analysis shows no aluminum or tin oxides on the surface of the electrode-tool, which attests to the presence of these oxides in the amorphous state or in the form of micro-disperse particles. 4. In the process of the electrospark alloying on the surface of the electrode-tool, the ratio between aluminum and tin changes, which depends on the parameters of the alloying (the energy of the pulse discharge, frequency of pulse repetition, rate of the electrode motion, value of the anode vibration, etc.): a) at low values of the pulse discharge energy, tin is transferred into the  coating in a small amount, or it is not transferred at all; b) at high values of the energy of the pulse discharge tin is extracted from the   anode and is transferred into the coating in great amounts, forming thus  micro-disperse and nanostructures in the form of nanofibers.