In this article, the fabrication, characterization, tribological performance, and micromechanical properties of nanostructured smart coatings (NSC) based on the multilayered alternating carbonitride/nitride bilayer {TiMe-CN/TiAlSi-N}n system are discussed. The symbol “Me” denotes refractory metals Hf or Nb, and the index “n” shows the number of superlattice periods. The NSC samples were deposited onto bearing steel (100Cr6) substrates using a reactive high-power physical vapor deposition (PVD) technique that can be scaled up for industrial use. The deposited multilayered NSC contained crystalline nanometer-scale TiMe-CN/TiAlSi-N nanoparticles strengthened by Hf or Nb additives, which increased surface microhardness up to 3000 HV. The measured steady-state friction coefficient (CoF) was within the 0.2–0.4 range, and a specific wear rate lower than 2 × 10⁻⁶ mm³/Nm was observed in the dry friction regime. The impact of NSC substrate hardness and NSC coating thickness on microhardness measurement values was investigated. A thicker coating provided a higher integrated (coating + substrate) microhardness value at a lower indentation test force (<0.3 N). As the indentation test force increased, the obtained microhardness values decreased faster for the coatings deposited on a softer substrate. The surface roughness impact on wear properties for specific NSC coatings was observed.

Ceramic Nanostructured Superlattice Coatings (NSC) have broad applicability to improve the parts’ and assemblies’ tribological and mechanical properties for the needs of the automotive and aerospace industries. Improving the material properties using nanocoatings for such a widely used material as, for example, bearing steel 100Cr6 makes it possible to improve the service life of machine parts. In this paper, the correlation dependence between tribological and mechanical properties of the NSC and its surface texture are considered to determine how much surface texture will affect the tribological performance of the coated workpieces, as well as the measuring and evaluation procedure of the nanocoatings, are presented. Three different NSC described by a general empirical formula {TiMe1Me2-CN/TiAlSi-N}n and based on the modified carbonitride/nitride non-stoichiometric chemical composition were created, and their tribological and mechanical properties measured and analyzed in the context with surface texture. NSC deposited by the advanced PVD (Physical vapor deposition) technique demonstrated significantly higher wear resistance (up to 28 times), reasonably lower friction coefficient (CoF) (up to 4 times), and significantly higher hardness of the coated workpieces (up to 7 times) versus substrate material. A strong correlation between the steady-state dry sliding friction, CoF, and the amplitude and functional surface texture parameters of tribo-track were observed. The first results of the initiated research regarding the correlation analysis of the tribological and mechanical properties, on the one hand, and surface texture, on the other hand, of the NSC are reported here.

Surfaces only characterized by a roughness Ra or Sa may have a totally different surface texture and include complex patterns such as grooves, dimples, or a mirror-polish. Here, the bearing ratio is proposed as an additional characterization measure to determine the sliding performance of a steel–ice friction pair. Different steel surfaces were produced by milling, shot blasting, and scratching, followed by texture assessment with a stylus type three-dimensional (3D) profilometer. The bearing ratio and other 3D roughness parameters were determined. Tribology experiments involved a 3 m long inclined plane tribometer and the speed measured at four points during the sliding experiment. Correlation between the steel sliding speed and the bearing ratio was observed under two different regimes: at warmer conditions and at colder conditions. Experiment 1 depicting warmer conditions exhibited a relative humidity of 64%, an air temperature of −2 °C, and an ice temperature of −9 °C. Experiment 2 for colder conditions showed a relative humidity of 78%, an air temperature of 1 °C, and an ice temperature of −4 °C. The sliding speed correlated with the bearing ratio in these two conditions showing −0.91 and −0.96, respectively. A strong correlation between the sliding speed and the bearing ratio shows the value of the bearing ratio as an additional surface characteristic for considering larger surface features.

Ice friction is influenced by multiple interconnected parameters between the sliding body and ice, making it a challenging research area in tribology. The motivation for this review lies in the need to understand the parameters affecting ice friction and its relevance to the fields of sport, safety and various industrial applications. The existing literature on ice friction only partially describes the test methods used. Thus, the comparability of the results and the drawing of conclusions are more challenging. This review addresses this issue by analysing factors affecting ice friction, including properties of the ice, liquid-like layer, sliding body and experimental methods. Small-scale rotary, linear, and large-scale laboratory and on-field setups are reviewed, and advantages and limitations are highlighted. The main results indicate that laboratory setups tend to provide more precise control over measurements but may not replicate real-world conditions. On the other hand, large-scale and on-field setups are closer to the actual conditions, but the control over experiments, reproducibility and implementation is more challenging. The review concludes that future research should focus on comparing different test methods with the possibility of developing standardised protocols and improving large-scale experimental setups. The study aims to enhance the reliability of ice friction research and its practical applications, which should lead to improved safety and performance in the fields where ice friction plays a crucial role.

Surface quality is crucial for precise micro-Vickers hardness measurements. Current standards provide limited quantitative guidance on acceptable surface roughness levels. This study examines the impact of varying surface roughness levels on measured hardness values and measurement accuracy for two materials: aluminium alloy 6082-T651 and stainless steel Uddeholm Ramax HH. For each material, six samples were prepared with distinct surface roughness levels (Sa from ~ 0.02 to 0.72 µm) and characterised by 3D surface texture measurements. Microhardness tests were conducted across a range of applied loads from 0.005 to 1 kgf. Higher surface roughness (Sa > ~0.2 µm) led to increased measurement variability, and larger differences in indentation diagonal lengths—effects most pronounced at test loads ≤ 0.1 kgf—whereas ISO 6507-1:2023 precision (coefficient of variation < 5%) was consistently achieved when roughness was reduced to Sa ≤ 0.05 µm for the aluminium alloy and Sa ≤ 0.07 µm for the stainless steel. A quantitative threshold based on the ratio of roughness to indentation depth (Sa/h) is proposed, offering practical limits for surface preparation. These findings highlight the importance of surface quality and provide new insights for enhancing the reliability of microhardness measurements in materials characterisation.

Frictional interaction with a surface will depend on the features and topography within the contact zone. Describing this interaction is particularly complex when considering ice friction, which needs to look at both the macroscopic and microscopic levels. Since Leonardo da Vinci shared his findings that roughness increases friction, emphasis has been placed on measuring surface coarseness, neglecting the contact area. Here, a profilometer was used to measure the contact area at different slicing depths and identify contact points. Metal blocks were polished to a curved surface to reduce the contact area; further reduced by milling 400 µm grooves or laser-micromachining grooves with widths of 50 µm, 100 µm, and 150 µm. Sliding speed was measured on an inclined ice track. Asperities from pileup reduced sliding speed, but a smaller contact area from grooves and a curved sliding surface increased sliding speed. An analysis of sliding speed versus contact area from incremental slicing depths showed that a larger asperity contact surface pointed to faster sliding, but an increase in the polished surface area reduced sliding. As such, analysis of the surface at different length scales has revealed different design elements—asperities, grooves, curved zones—to alter the sliding speed on ice.