The formation of graphite films at micrometric and nanometre scale on the surfaces of alloys-made parts causes their diffusion in the surface layer accompanied by the formation of high hardness carbides, and, as a result, the wear resistance of this layer increases [1-5]. TGA tests on graphite films were conducted on a Du Pont Instruments 951 device. In order to avoid errors – due to the oxidative process that takes place at high temperature and results in a weight increase – TGA tests on graphite films were carried out in nitrogen atmosphere. The following parameters were set for the reference sample and for the graphite deposit material on the surface of the work piece: 20800 ° C temperature range; 10 °C/min heating rate; medium N2 analysis at a working pressure of 760 mm Hg. First of all, TGA tests were done on a pure graphite sample, which was thought to be the reference sample. The curve shape does not reveal any unusual thermal behaviour for graphite; within the temperature range of 100-280 °C a weight loss of 7.485% (0.4683 mg) occurs as a result of volatiles and water evaporation; between 280-600 °C no weight loss occurs which shows a high thermal stability of graphite; some non-significant decomposition (of about 18% of baseline) occurs within the temperature range of 650-800 °C, caused by decomposition of tars and heavy hydrocarbons that are found in most varieties of graphite and, finally, considerable amount of graphite is found in the residue – more than 75%, at the end of determination 800 °C. These aspects are characteristic for graphite behaviour. TGA curve of deposited graphite sample shows a completely different allure from that characteristic of pure graphite. The graph shows a number of very interesting aspects suggesting that the graphite film, deposited by electrical discharge in impulse, has a completely different structure from that of pure graphite or that, besides graphite, other chemical compounds of carbon are formed [6]. One may notice that within 200-300 0C temperature range (at 222.99 0C) a significant weight increase (of 1.999 %) occurs, showing that the graphite sample gains weight, instead of losing it due to decomposition or loss in volatiles – showing a material adsorption in graphite film structure (as the adsorbed material cannot be anything but nitrogen from the atmosphere in which the tests are run)