The paper presents the results and provides an analyse of the geometric structure of Fe-Al protective coatings, gas-treated under specified GDS conditions. The analysis of the surface topography was conducted on the basis of the results obtained from the SEM data. Topographic images were converted to three-dimensional maps, scaling the registered amplitude coordinates of specific gray levels to the relative range of 0÷1. This allowed us to assess the degree of surface development by determining the fractal dimension. At the same time, the generated three-dimensional spectra of the autocorrelation function enabled the researchers to determine the autocorrelation length (Sal) and the degree of anisotropy (Str) of the surfaces, in accordance with ISO 25178. Furthermore, the reconstructed three-dimensional images of the topography allowed us to evaluate the functional properties o the studied surfaces based on the Abbott-Firestone curve (A-F), also known as the bearing area curve. The ordinate describing the height of the profile was replaced by the percentage of surface amplitude in this method, so in effect the shares of the height of the three-dimensional topographic map profiles of various load-bearing properties were determined. In this way, both the relative height of peaks, core and recesses as well as their percentages were subsequently established.

The paper presents results of a research on simulation of magnetic tip-surface interaction as a function of the lift height in the magnetic force microscopy. As expected, magnetic signal monotonically decays with increasing lift height, but the question arises, whether or not optimal lift height eventually exists. To estimate such a lift height simple procedure is proposed in the paper based on the minimization of the fractal dimension of the averaged profile of the MFM signal. In this case, the fractal dimension serves as a measure of distortion of a pure tip-surface magnetic coupling by various side effects, e.g. thermal noise and contribution of topographic features. Obtained simulation results apparently agree with experimental data.

The influence of the processing temperature of polylactide (PLA) on the structure geometry changing (SGC) and its functional properties were analyzed. The PLA samples subjected to testing were manufactured using incremental fused deposition modeling technology (FDM) with processing temperatures ranging from 180°C to 230°C. The topography of the PLA surfaces formed during heat dissipation and generated by the work table was analyzed. The roughness measurements were carried out using the profile method in accordance with PN ISO 3274: 2011. Registered profiles of the surfaces were analyzed numerically in fractal terms using the method of the S(Δx) structure function. The functional properties of the PLA surface were evaluated on the basis of Abbott-Firestone curves, according to PN EN ISO 13565–2: 1999.