High consumption of citrus, particularly oranges, coupled with significant postharvest losses due to microbial spoilage and physical damage have positioned them as a suitable model system for investigating the functional properties of novel active bilayer edible coatings. This study conceptualized a bilayer system comprising a protein-based inner layer for adhesion and a lipid-based outer layer enriched with cinnamon essential oil for enhanced barrier and antimicrobial properties. Optimization of the inner layer preparation, including adjusting soy protein/gelatine ratio, concentration, and solution pH, alongside gradual drying, resulting in a smooth, flexible film with improved barrier properties compared to neat soy protein and gelatine films. The second layer, formulated with cocoa butter and linseed oil incorporating cinnamon essential oil as a natural antimicrobial agent significantly enhanced barrier properties and exhibited potent antimicrobial activity against Penicillium spp. The obtained bilayer system demonstrated improved elongation at the break (exceeding 220 %) and a low water vapor transmission rate (WVTR) of 0.98 g/(m2 & sdot;h), comparable to commercial polymers like PLA and PA. This research demonstrates the potential of innovative and sustainable active bilayer coating to significantly reduce postharvest losses in citrus fruits while minimizing the reliance on synthetic fungicides.

Aluminium alloys are extensively employed across modern industries, appreciated for their advantageous combination of low weight, corrosion resistance, strength, and ductility. Nonetheless, casting defects—including inclusions, porosity, hydrogen absorption, and particularly bifilms—can significantly compromise the mechanical properties of cast components. The present investigation centres on bifilm-related defects, which originate from the oxidation behaviour of aluminium alloys. Upon exposure to air, a thin oxide layer instantly forms on the molten metal surface. When disrupted, this film is immediately replaced by a new one, and such layers can become entrained within the melt during various stages of processing. Once inside the liquid metal, these oxide films retain their structural integrity due to their inert nature, remaining as compacted and folded entities that do not dissolve or disperse. Their presence has a pronounced negative impact on mechanical properties and can result in internal discontinuities that reduce mechanical properties and manifest as leak paths after machining. While bifilms can be introduced during melting, charging, or refining, the pouring phase presents a critical opportunity for their entrapment. Thus, the design of the gating system becomes essential. In this preliminary study, the role of flow dynamics during mould filling was examined by comparing two distinctly configured gating systems in sand casting of aluminium alloy: a top-gated setup promoting turbulent flow, and a bottom-gated arrangement intended to minimize flow disturbance. Advanced simulation using Magmasoft software confirmed the expected flow behaviours, illustrating greater splashing and air entrapment in the top-gated configuration. Following casting, samples were machined and subjected to tensile testing. Results demonstrated a statistically significant increase in ultimate tensile strength for specimens produced via the bottom-gated system. This exploratory experiment lays the groundwork for continued investigations into bifilm mitigation through optimized gating design.

Nitinol is widely used for orthodontic archwires due to its favourable mechanical properties and corrosion resistance. To maintain oral hygiene and prevent dental plaque, orthodontic patients are advised to use commercially available mouthwashes, many of which contain chlorine- or fluorine-based compounds. These compounds can interact with the surface oxide layer of NiTi alloy, potentially leading to its degradation and the release of toxic nickel ions into the surrounding biological environment. The detrimental effects of chlorine- and fluorine-containing media on NiTi are well-known. However, due to the typically low intensity of the corrosion processes, the characterization of surface corrosion effects in such environments remains a great challenge. In this study, non-electrochemical corrosion tests were conducted on NiTi archwires exposed to artificial saliva and several commercially available mouthwashes to quantify nanometric changes in surface topography. Corrosion effects were evaluated using atomic force microscopy (AFM) in contact mode, with measurements taken at predefined surface locations before and after the corrosion tests. The topographical changes were evaluated using surface roughness parameters: Sa, Ssk, Sdr, and S10z. The analysis revealed that mouthwashes containing chlorine compounds resulted in both material loss and gain on the surface, while fluorine-based mouthwashes caused only material loss. In contrast, samples exposed to artificial saliva exhibited no significant topographical changes. The analytical approach developed in this study proves effective for identifying and distinguishing types of nanoscale surface alterations associated with corrosion. The observed material gain in chlorine-containing mouthwashes is likely due to surface reoxidation, a phenomenon not present in fluorine-containing solutions

In this study, we used the depth-sensing indentation technique to determine the cracking resistance of different PVD hard coatings deposited on tool steel substrates. By comparison, with the load–displacement curves, measured at the sites of carbide inclusion and a tempered martensite matrix in the D2 tool steel substrate surface, we observed different fracture mechanisms on TiAlN hard coating prepared by sputtering. Additional information about the deformation and fracture phenomena was obtained from the SEM images of FIB cross-sections of both types of indents. We found that the main deformation mechanism in the coating is the shear sliding along the columnar boundaries, which causes the formation of steps on the substrate surface under individual columns. Using nanoindentation test, we also analyzed the cracking resistance of a set of nl-(Cr,Al)N nanolayer coatings with different Cr/Al atomic ratios, which were sputter deposited in a single batch. From the indentation curves, we determined the loads (Fc) at which the first pop-in appears and compared them with the plasticity index H3/E2. A good correlation of both parameters was found. We also compared the indentation curves of the TiAlN coating, which were prepared by cathodic arc evaporation using 1-fold, 2-fold and 3-fold rotation of the substrates. Additionally, on the same set of samples, the fracture toughness measurements were performed by micro-cantilever deflection test. The impact of growth defects on the cracking resistance of the hard coatings was also confirmed.

Reports of the influence of surface roughness on the adhesion and tribological performance of contemporary nitride coatings with different layer designs are still scarce in the literature. Therefore, in this study, we evaluated the behavior of a single-layer TiAlN, a bilayer TiAlN/CNx, and a nanolayer AlTiN/TiN coating. Coatings were deposited in an industrial magnetron sputtering unit on the substrates of EN 100Cr6 steel, prepared to four degrees of surface roughness (Sa = 10–550 nm). The coatings’ adhesion was determined by scratch tests performed perpendicular and parallel to the machining marks. Dry reciprocating sliding tests in air were employed to evaluate the coatings’ tribological behavior against an Al2O3 ball. Before and after the tests, coating properties were characterized by 3D profilometry, confocal microscopy, and energy dispersive spectroscopy. Deposition of all coatings significantly altered the surface topography and increased the roughness of the samples. No general rule could be established for the effect of surface roughness on tribological behavior and adhesion of different hard coatings. For very fine surface finishes the adhesion and tribological performance of TiAlN and TiAlN/CNx coatings was independent of the surface roughness. For the roughest surfaces, a decrease in adhesion and an increase in the wear rate were observed. The AlTiN/TiN coating exhibited the largest sensitivity of adhesion to roughness and scratching direction. The coefficient of friction and wear rate increased when AlTiN/TiN roughness exceeded Sa ≈ 100 nm.

Due to affordability, and the ability to parametrically control the vital processing parameters, material extrusion is a widely accepted technology in tissue engineering. Material extrusion offers sufficient control over pore size, geometry, and spatial distribution, and can also yield different levels of in-process crystallinity in the resulting matrix. In this study, an empirical model based on four process parameters-extruder temperature, extrusion speed, layer thickness, and build plate temperature-was used to control the level of in-process crystallinity of polylactic acid (PLA) scaffolds. Two sets of scaffolds were fabricated, with low- and high-crystallinity content, and subsequently seeded with human mesenchymal stromal cells (hMSC). The biochemical activity of hMSC cells was tested by examining the DNA content, lactate dehydrogenase (LDH) activity, and alkaline phosphatase (ALP) tests. The results of this 21-day in vitro experiment showed that high level crystallinity scaffolds performed significantly better in terms of cell response. Follow-up tests revealed that the two types of scaffolds were equivalent in terms of hydrophobicity, and module of elasticity. However, detailed examination of their micro- and nanosurface topographic features revealed that the higher crystallinity scaffolds featured pronounced nonuniformity and a larger number of summits per sampling area, which was the main contributor to a significantly better cell response.

In this study, high-temperature tribological behavior of nanolayered TiAlN/TiSiN coating was evaluated against the Al2O3 counter-body using a pin-on-disk tribometer. The coating was deposited on the WC-Co substrate, in an industrial unbalanced magnetron sputtering system. Tribological tests were conducted at room temperature, 500, 600, 700, and 760 degrees C, in air and nitrogen atmospheres. After the tests, the coating was examined using confocal microscopy, tactile profilometry, scanning electron microscopy, focused ion beam, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The coating retained its microstructure and mechanical properties after exposure to high temperatures. At lower temperatures coating exhibited abrasive and adhesive wear mechanisms, while at higher temperatures abrasive and oxidative wear mechanisms were observed. In high-temperature tests, Al-O, Ti-O and Si-O were detected inside of wear tracks, in both atmospheres. However, the oxide thickness was significantly lower in tests with nitrogen atmosphere. Additionally, the top of the oxide layer was enriched in Al-O with respect to Ti-O and Si-O. The enrichment of Al-O was more pronounced in nitrogen atmosphere. The coating tested in air exhibited slightly higher and more unstable coefficient of friction (COF) values, than in nitrogen atmosphere. This is attributed to the increased oxidation in air atmosphere. At room temperature tests in nitrogen, the wear rate was approximately 3 times lower than in air. At higher temperatures the wear rate was lower than at room temperature, in both atmospheres, due to formation of protective oxides. However, with the increase in testing temperature the wear rate increased. The reason for such behavior is the loss of substrate's and coating's hardness at high temperatures, and thickening of the oxide layer which accelerated its removal. The latter effect is not so pronounced in nitrogen atmosphere due to thinner oxide layer, which agrees with the lower wear rate in nitrogen atmosphere at high temperatures than in air.

In the present study, (Cr,Al)N nanolayer coatings with different Al/Cr atomic ratios were deposited by magnetron sputtering on different substrate materials (H11 and D2 tool steel, alumina). To prepare the (Cr,Al)N coatings with different Al/Cr atomic ratios in the same batch, we used two targets composed of two triangle-like segments together with two standard Al and Cr targets. This approach enabled us to study the evolution of structural and mechanical properties in dependence on composition. The elemental composition of the coatings was determined by energy-dispersive X-ray analysis (EDS). The phase composition of the (Cr,Al)N coatings was determined utilizing X-ray diffraction (XRD), while scanning electron microscopy (SEM) was employed to assess their morphology and microstructure. The coating surface topography was analyzed by atomic force microscopy (AFM). In order to evaluate the effect of the Al/Cr atomic ratio on the oxidation behavior, the (Cr,Al)N coatings were oxidized in ambient atmospheres at temperatures between 700 and 850 °C and subsequently analyzed by means of cross-sectional SEM and transmission electron microscopy (TEM). The oxidation rate, determined by weight gain over time, was utilized to quantify the oxidation process. The oxidation tests showed that the Al-rich (Cr,Al)N nanolayer coatings exhibit a considerably better oxidation resistance than the Cr-rich ones. We found that the oxide scale formed on the Al-rich coating is composed of double layers: a Cr-oxide top layer and an inner (Cr,Al) mixed oxide layer. In contrast, the oxide scale of the Cr-rich coating mainly consists of the Cr2O3 layer. In particular, we focused on the oxidation process occurring at the locations of growth defects. We noticed that the first oxidation products on the coated substrate occurred at a temperature that was much lower than the temperature for the (Cr,Al)N coating oxidation initiation. These products (iron oxides) formed only at the sites of those growth defects that extended through the entire coating thickness.

Biodegradable thin films based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(caprolactone diol) (PCL-diol) blend were developed using the solution casting method. PHBV is biodegradable, biocompatible, and produced naturally by bacterial activity, but its use is restricted by high crystallinity and low resistance to thermal degradation with melting temperatures close to degradation thus narrowing the processing window. Solution casting was chosen as a cost-effective method reducing energy consumption and avoiding thermal degradation during processing. The increase in PCL-diol in blend composition (40-60 wt%) enhances the film-forming ability of PHBV and the wettability along with the decrease in the roughness of the resulting materials as revealed by contact angle measurements, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Optimal composition in terms of filmogenity and surface structure has been achieved by the addition of PCL-diol in the amount of 60 wt%. FTIR confirmed the expected chemical structures with no evidence of chemical interactions between the two polymers.

An active packaging based on the composite film was developed by incorporation of oregano oil as an antimicrobial agent into a cellulose acetate/polycaprolactone diol blend (CA/PCL-diol). A novel plasticizer based on polyethylene terephthalate (PET) glycolysis product (bis(hydroxyethyl terephthalate)) and tartaric acid was synthesized and its influence on the structural, surface, mechanical, barrier, and thermal properties were investigated. The obtained results have shown that plasticizer also has a compatibilizing effect, improving the miscibility of polymers in a blend. A sample with the optimal amount of plasticizer (30 wt%), as well as the best mechanical and barrier properties, was used for the preparation of series with different amounts of oregano oil (3, 6, and 9 wt%). The synthesized azo dye—5-(4-bromo-phenyl azo)-3-amido-6-hydroxy-4-methyl-2-pyridone, soluble in acetone, as well as a blend and plasticizer, has been shown as an adequate one for this composition, due to its ability to achieve a good pigmentation in a low amount (0.3 wt% per polymer blend weight), to absorb UV light, and decrease the aging of the material. Contemporary lifestyle has imposed a need for ready-to-eat (RTE) meals which saves consumers time. RTE food packaging should meet certain requirements such as the ability to prolong shelf-life and preserve the freshness of the food product, and at the same time to make a minimal amount of waste after usage, considering the fact that it is mostly single-use plastic food packaging. Optimal mechanical properties, biodegradability, and additional functions make these films suitable for the packaging of ready-to-eat (RTE) food such as fresh salad.

Nitinol (NiTi) alloy is a widely used material for the production of orthodontic archwires. Its corrosion behavior in conditions that exist in the oral cavity still remains a great characterization challenge. The motivation behind this work is to reveal the influence of commercially available mouthwashes on NiTi orthodontic archwires by performing non-electrochemical corrosion tests and quantifying the changes in the nanotopography of commercially available NiTi orthodontic wires. In this study, we examined the behavior of NiTi alloy archwires exposed for 21.5 days to different corrosive media: artificial saliva, Eludril®, Aquafresh®, and Listerine®. The corrosion was characterized by contact mode atomic force microscopy (AFM) before and after the corrosion tests. A novel analysis methodology was developed to obtain insight into locations of material gain or material loss based on standard surface roughness parameters Sa, Sdr, Ssk, and S10z. The developed methodology revealed that fluoride-containing mouthwashes (Aquafresh® and Listerine®) dominantly cause material loss, while chloride-containing mouthwash (Eludril®) can cause both material loss and material gain. The sample exposed to artificial saliva did not display significant changes in any parameter.

In this paper, we present a comparative study of tribological properties of TiN coatings deposited by low-voltage electron beam evaporation, magnetron sputtering and cathodic arc deposition. The correlation of tribological behavior of these coatings with their intrinsic properties and friction condition was studied. The influence of surface topography and the surrounding atmosphere was analyzed in more detail. We limited ourselves to the investigation of tribological processes that take place in the initial phase of the sliding test (the first 1000 cycles). A significant difference in the initial phase of the sliding test of three types of TiN coatings was observed. We found that nodular defects on the coating surface have an important role in this stage of the sliding test. The tribological response of TiN coatings, prepared by cathodic arc deposition, is also affected by the metal droplets on the coating surface, as well as those incorporated in the coating itself. Namely, the soft metal droplets increase the adhesion component of friction. The wear rates increased with the surface roughness of TiN coatings, the most for coatings prepared by cathodic arc deposition. The influences of post-polishing of the coating and the surrounding atmosphere were also investigated. The sliding tests on different types of TiN coatings were conducted in ambient air, oxygen and nitrogen. While oxygen promotes tribo-chemical reactions at the contact surface of the coating, nitrogen suppresses them. We found that the wear rate measured in ambient air, compared with that in an oxygen atmosphere, was lower. The difference is probably due to the influence of humidity in the ambient air. On the other hand, wear rates measured in a nitrogen atmosphere were much lower in comparison with those measured in an oxygen or ambient air atmosphere.

This study aims to contribute to the better understanding of results obtained by different methods used for high temperature tribological evaluation of hard coatings. For these purposes tribological testing directly at high temperatures and testing of annealed coatings at room temperature were compared. In this study, high temperature tribological behavior of 3 μm thick TiAlN coating (3050 HV0.05) was evaluated using high temperature pin-on-disk tribometer. Coating was prepared on EN X38CrMoV5 steel samples using cathodic arc deposition. Coated samples were tested against Al2O3 ball, in air atmosphere, at room temperature, 300 °C, 500 °C, 600 °C, and 700 °C, and after being previously annealed (PA) at these temperatures. Stylus profilometry, confocal microscopy, focused ion beam, and energy dispersive spectroscopy were employed for evaluation of the wear tracks. At room temperature (RT) the steady-state COF was 0.72. Tribo-tests at 300 °C and 500 °C resulted with steady COF which slightly increased to a maximum value of 0.7 and 1, respectively. COF for tests at 600 °C and 700 °C, after reaching a max value of 0.95 and 0.85, declined for both cases. Each of the tribo-tests on PA samples displayed COF values similar to RT tests, but with pronounced oscillations. Tribo-tests at RT and on PA samples produced similar wear tracks that displayed combination of both adhesive and abrasive wear mechanism, while abrasive and oxidative wear mechanism was observed at high temperatures. At 600 °C coating degradation due to oxidation of substrate initiated, and at 700 °C coating was completely damaged. It is suggested that declining COF at 600 °C and 700 °C is due to formation of Fe-O and Cr-O inside of wear tracks. Additionally, oscillations of COF on PA samples are suggested to be the consequence of adhesive wear of coatings. Finally, detailed analysis revealed that, apart from their COF, tribo-tests on PA samples are quite similar to RT tests, but significantly differ from high temperature tests.

High pressure die casting (HPDC) is one of the most commonly used technologies for processing of Al-alloys. Die degradation occurs due to different wear mechanisms such as corrosion (soldering), erosion and thermal fatigue. Soldering is a form of corrosion process in which the interaction of cast alloy and tool surface form layers of built-up material that reduce the die performance and castings quality. To mitigate the soldering problems application of nanolayer coatings containing transitional metal nitrides such as CrN, AlN and CrAlN is advised. However, the performance of CrAlN coatings with different chemical composition is still scarce in the literature. Therefore, this study concerned nanolayered CrAlN coating, with three chemical compositions, deposited on plasma nitrided hot-working tool steel. Soldering of the coating to the Al-alloy was evaluated using a detachment test. The contact surfaces were analyzed using a profilometer, focused ion beam (FIB), scanning electron microscopy (SEM) X-ray spectroscopy (XPS). By analyzing the samples' contact surfaces, it was found that soldering and oxidation occurred on the contact surface and through coating defects. These phenomena have manifested as intermetallic compounds, which formed between Al-alloy and the underlying substrate. Samples with higher number of coating defects exhibited a larger amount of soldering. In detachment test, as a result of soldering, a coating layer detached from the substrate together with the casting. This enabled the analysis of the coating back side and the intermetallic compounds that formed through coating defects. These compounds deteriorated the contact surface between the substrate and the coating. This compromised the contact surface of the coating and the substrate material, which lead to coating delamination. It was found that the chemical composition of the coating had a minor influence on soldering than the density of growth defects. The samples with less defects exhibited less soldering. By reducing the number of coating defects, tool life can be extended.

High pressure die casting (HPDC) is a progressively developing technology used for mass production of complex, near-net shape and thin-walled components of light alloys. Its production efficiency greatly depends on a die quality and its endurance. Nowadays this is usually improved by application of ceramic coatings produced by physical vapor deposition (PVD) on its surfaces. However, future development of these coatings still requires fundamental knowledge about oxidation and corrosion mechanisms acting in these specific cases. Therefore, we investigated the performance of plasma nitrided steel, duplex CrN and TiAlN PVD coatings prepared to different degrees of surface roughness. Corrosion behaviour in Al-Si-Cu cast alloy was evaluated by ejection test, performed with conventional (CS) and delayed cast alloy solidification (DS) for 5 and 20 min. Beside corrosion in a casting process this test simulates the ejection process of a die core from a casting. The force required for ejection is a measure of cast alloy soldering (corrosion) tendency toward pin material. Different microscopy and analytical techniques were employed for the analysis of samples surfaces after the ejection tests. On all samples subjected to CS tests cast alloy built-up layer formed due to galling and mechanical soldering effects. In conditions of DS tests, plasma nitrided sample was attacked by aluminium, a corroded layer formed which easily sheared under lower force during the ejection process. On the other side, lower ejection force recorded in DS tests for smoother coated samples is attributed to the thickening of the casting oxide scale that occurred due to the consumption of oxygen from coatings oxide layers. For both coatings, in DS tests, a nondetrimental corrosion of underlying nitrided substrate occurred through the coating growth defects. Results of focused ion beam analysis of different corrosion sites revealed the morphology and chemistry of corrosion products which suggested possible mechanisms that act in such processes.

Coatings deposited by physical vapor deposition (PVD) significantly reduce the wear of high pressure die casting tools; however, cast alloy soldering still has a strong negative effect on production efficiency. Although a lot of research has been already done in this field, the fundamental understanding of aluminum alloy soldering toward PVD coatings is still scarce. Therefore, in this work the performance of CrN duplex coatings with different roughness is evaluated by a modified ejection test performed with delayed (DS) and conventional casting solidification (CS). After the ejection tests, sample surfaces and layers were subjected to comprehensive characterizations of their morphological and chemical characteristics. Considerably lower values of the ejection force were recorded in DS experiments than in CS experiments. Surface roughness played an important role in the CS experiments, while samples with different surface topographies in the DS experiments performed in a similar fashion. The decrease in the ejection force, observed in DS tests, is attributed to the formation of a thick Cr–O layer on CrN coating which reduced soldering and sliding friction against thick Al–O casting scale. The Cr–O layer formed in DS experiments suffered from diffusion wear by cast alloy. The observed oxidation phenomena of nitride coatings may be utilized in a design of non-sticking coatings.

Nanolayer TiAlN/TiSiN coating is one of the most advanced contemporary protective coatings. It has been applied for protection of machining tools, forming tools, and die casting tools. However, due to its versatile properties, there is a high potential for broadening its application; for example, for protection of biomedical implants. Each application requires specific base materials, for example cold working steels are used for forming, while stainless steels are applied for biomedical purposes. Different materials and their pre-treatment might result in different coating properties even if coating was conducted in a single batch. Real tools and components have complex geometries, and as such require a multiple-axis rotation during the deposition. Among other properties, grain morphology and surface topography are of great importance in a real application. Since systematic studies on the effect of substrate materials and rotation during deposition on these properties are very scarce, in this article we studied TiAlN/TiSiN coating magnetron sputtered on five different substrates, prepared with 1-, 2-, and 3-fold rotations. Cold-work tool steel (X153CrMoV12), hot-work tool steel (X37CrMoV5-1), plasma-nitrided hot-work tool steel, surgical stainless steel (X2CrNiMo18-15-3), and cemented carbide (WC/Co) were used as substrate materials. Three-dimensional stylus profilometry and atomic force microscopy were used for evaluation of micro and nano topography. The coated surgical steel has the highest roughness (Sa) which corresponds to the highest number of coating growth defects. However, the size of the individual growth defects was considerably smaller for this substrate than for other substrate materials. The observed difference is linked to differences in the concentration of specific carbides contained in a specific steel. Since different carbides have different polishing and ion-etching rates, coatings on different steels may have different concertation of defects. Columnar grain analysis revealed that coating on surgical steel exhibited the smallest column diameter (125 nm) and their highest uniformity. Column diameter on other substrates is around 215 nm, while hot-working tool steel exhibited the largest columns (235 nm). Such findings suggest that the same coating may exhibit different mechanical properties on different substrates. Coatings produced with the higher degree of rotation (2-fold, 3-fold) have fewer defects and a smoother surface. There was no clear trend between columnar grain size and the number of rotational degrees.

With the goal to produce a hard and tough coating intended for tribological applications, CrAlN/TiSiN nanolayer coating was prepared by alternative deposition of CrAlN and TiSiN layers. In the first part of the article, a detailed study of phase composition, microstructure, and layer structure of CrAlN/TiSiN coating is presented. In the second part, its mechanical properties, fracture and tribological behavior are compared to the nanocomposite TiSiN coating. An industrial magnetron sputtering unit was used for coating deposition. X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used for compositional and microstructural analysis. Mechanical properties and fracture behavior were studied by instrumented indentation and focused ion beam techniques. Tribological properties were evaluated by ball-on-disk test in a linear reciprocal mode. A complex layer structure was found in the nanolayer coating. The TiSiN layers were epitaxially stabilized inside the coating which led to formation of dislocations at interfaces, to introduction of disturbances in the coating growth, and as a result, to development of fine-grained columnar microstructure. Indentation load required for the onset of fracture was twice lower for the nanolayer CrAlN/TiSiN, compared to the nanocomposite TiSiN coating. This agrees very well with their mechanical properties, with H3/E2 being twice higher for the TiSiN coating. However, the nanolayer coating experienced less severe damage, which had a strong impact on tribological behavior. A magnitude of order lower wear rate and four times lower steady state friction coefficient were found for the nanolayer coating.

During the high pressure die casting (HPDC) process the die material is exposed to thermal fatigue, erosion, and corrosion. Corrosion leads to the soldering of cast alloy to tool surfaces which consequently bonds the casting with die material. Besides wear, such a process reduces the casting quality and production efficiency and endangers the tool integrity. Application of thin ceramic coatings on die surfaces reduces the soldering effects and improves the die performance. However, the development of ceramic coatings for these purposes still requires detailed information on the phenomena involved in these processes. In this study, the soldering performance of a complex nanolayer CrAlN coating, with three chemical compositions (high-Cr, balanced Cr:Al, and high-Al content) were evaluated. The cast alloy soldering was evaluated by the detachment test in three configurations. In this test, a simple casting is formed in contact with flat coated surfaces. Upon casting solidification, the formed joint is dismantled, and a force required for this process was recorded. To characterize and quantify the exhibited wear, after the detachment test, surfaces of the coated samples were analyzed by different microscopy techniques. Two forms of wear were detected on investigated samples. Cast alloy soldering processes induced the formation of thin layers of cast alloy on the surfaces of all investigated coatings. Additionally, substrate corrosion through the coating growth defects caused coating layer delamination during the detachment test. The evaluated coatings displayed different behaviors regarding the extent of wear and values of the detachment force. The coating with a balanced CrAlN composition exhibited the best soldering and corrosion resistance and displayed the lowest ejection force. In terms of soldering and corrosion resistance, the high-Al coating outperformed the high-Cr content coating. However, high-Al and high-Cr coating exhibited significantly higher and quite comparable values of detachment force. Based on the quantitative results it was postulated that, besides soldering and substrate corrosion, the casting-coating bonding strength depends also on "pure" sticking effects of cast alloy to coated surfaces.