Contact Lens Wear Research Articles

Influence of Applied Load and Sliding Distance on Wear Performance of AlSi7Mg0.6 Aluminum Alloy

The wear performance of AlSi7Mg0.6 aluminum alloy, a casting aluminum alloy used in positioning devices for catenary systems of high-speed railways which fail frequently on lines where the speed of trains is higher than 300 m/s, is discussed in this study. It was estimated that sliding contact wear occurred and mainly contributed to the failure. To explore the competing mechanism for frictional wear failure, frictional experiments based on three groups of sliding distance (0.5 mm, 1.5 mm and 3.0 mm) and four groups of applied loads (20 N, 50 N, 100 N and 200 N) were implemented. Three-dimensional morphological observation results revealed that the wear volumes at a sliding distance of 0.5 mm were only about 1/10 of that at a sliding distance of 3.0 mm. It was also revealed that the wear volume based on a sliding distance of 3.0 mm and applied load of 20 N was still much larger than the wear volume under a sliding distance of 0.5 mm and applied load of 200 N. SEM observation of the microstructures revealed that abrasive wear was the dominant wear mechanism in dry sliding friction conditions. A simplified positioning device model was also established to study the influence of tension force on wear performance. The simulation results revealed that smaller tension force between the positioning support and positioning hook would lead to higher relative sliding distance and larger wear depth. Sliding contact friction should be avoided due to relatively large wear efficiency compared with rolling contact friction. Both experimental and simulation results suggested that proper tension force was preferred in assembling components which could ensure rolling contact friction rather than sliding contact friction.

Experimental study on the effect of solid lubricants on wheel rail contact wear and surface hardness evolution

PurposeThe CL60 steel wheels of subway vehicles operating on specific lines require frequent refurbishment due to rapid wear and tear. Considering this issue, MoS2-based and graphite-based solid lubricants are used to reduce the wear rate of subway wheels and extend their service life.Design/methodology/approachUnder laboratory conditions, the effect of MoS2-based and graphite-based solid lubricants on the friction and wear performance of subway wheels and rails was evaluated using a modified GPM-60 wear testing machine.FindingsUnder laboratory conditions, MoS2-based solid lubricants have the best effect in reducing wheel/rail wear, compared to the control group without lubrication, at 2 × 105 revolutions, the total wheel-rail wear decreased by 95.07%. However, when three types of solid lubricants are used separately, the hardness evolution of the wheel-rail contact surface exhibits different characteristics.Practical implicationsThe research results provide important support for improving the lifespan of wheel and rail, extending the service cycle of wheel and rail, reducing the operating costs of subway systems, improving the safety of subway systems and providing wear reduction maintenance for other high wear mechanical components.Originality/valueThe experiment was conducted through the design and modification of a GPM-60 testing machine for wear testing. The experiment simulated the wheel-rail contact situation under actual subway operation and evaluated the effects of three different solid lubricants, MoS2-based and graphite-based, on the wear performance and surface hardening evolution of subway wheel-rail.

Successful treatment of multidrug-resistant Pseudomonas aeruginosa keratitis with meropenem eye drops — a case report

BackgroundThis case report describes the course and therapeutic management of a fast-spreading bacterial keratitis caused by multidrug-resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa).Case presentationA 27-year-old male contact lens wearer presented with a multi-resistant, fast spreading P. aeruginosa keratitis. After initial resistance to various antibiotic therapies, testing revealed a MDR P. aeruginosa. The keratitis was treated successfully with specially prepared 50 mg/ml off-label meropenem eye drops for 18 days as well as systemic meropenem for seven days with rapid improvement of the corneal infiltrate.ConclusionThis case report demonstrates the combination of topical and systemic meropenem as a useful treatment option for corneal ulcers caused by MDR P. aeruginosa.

Comparison Between Ocular Biometric Parameters and Intraocular Pressure With and Without Contact Lenses.

To compare the values of central corneal thickness, anterior chamber depth (ACD), lens thickness (LT), vitreous length (VL), axial length (AL), and corneal-compensated intraocular pressure performed with and without contact lenses (CL). Forty volunteer participants (16 men and 24 women, 24.2±2.9 years) were recruited. In a single visit, participants underwent autorefraction, keratometry, biometry, topography, pachymetry, and tonometry with the naked eye (without CL). Then, biometry, pachymetry, and tonometry were repeated twice wearing two CL (somofilcon A and nesofilcon A) fitted in a random order. Many of the ocular biometric values were affected by the use of CL during measurements (paired t test; all P ≤0.003), except for LT and VL (Wilcoxon test; both P ≥0.272). Corneal-compensated intraocular pressure was also affected by contact lens wear during measurements, obtaining lower values when wearing them (Wilcoxon test; all P ≤0.001). Central corneal thickness, ACD, AL, and corneal-compensated intraocular pressure measurements cannot be performed while wearing CL. However, LT and VL measurements were not affected by any contact lens use. In addition, it was observed that ACD results from both devices are not interchangeable either when measured with the naked eye or using any contact lens.

Impacts of vehicle light-weighting on wheel wear and RCF and a novel ultralight vehicle design

Vehicle light-weighting is a critical design target for rail vehicles, as it reduces energy consumption and enhances the vehicle capacity and dynamic performance, making the railway system more attractive in addressing the rising environmental challenges and increasing demand in transportation. This paper presents a quantitative analysis of the impact of vehicle light-weighting on wheel wear and rolling contact fatigue (RCF), using the USFD wear law, the shakedown map and the Tγ approach. A conventional metro vehicle is utilized as a baseline model, and the mass reductions from different vehicle components (i.e., car-body, bogie frame and wheelset) are implemented for the simulation considering various running scenarios. The effect of mass reduction on wheel wear can be divided into two aspects: quasi-static wheel load and wheel-rail dynamic interaction. In short-radius curves, the change in static axle-load predominantly determines wheel wear, whereas in large-radius curves and tangent track, the wheel-rail dynamic interaction plays an important role, thus showing different rates of wear reduction when mass reduction is achieved respectively from car-body, bogie frames and wheelsets. Reducing vehicle mass can significantly reduce wheel damage of RCF on short-radius curves with curve radii above 400 m, while there is a risk of increasing RCF on tight curve R250, due to the impaired function of wear to counteract the crack propagation. This work also exhibits a specific innovative ultralight vehicle design, where the linear synchronous motor technology is applied to reduce substantially the mass of the vehicle without impairing the capability to provide the required amount of tractive effort. The proposed ultralight vehicle can reduce the wheel wear by approximately 40% and shows substantial benefit for preventing RCF damage, compared to a conventional vehicle.

The Biocompatibility Analysis of Artificial Mucin-Like Glycopolymers.

The ocular surface is covered by a tear film consisting of an aqueous/mucin phase and a superficial lipid layer. Mucins, highly O-glycosylated proteins, are responsible for lubrication and ocular surface protection. Due to contact lens wear or eye disorders, lubrication of the ocular surface can be affected. Artificial glycopolymers which mimic natural mucins could be efficient in ophthalmic therapy. Various neutral, positively, and negatively charged mucin-mimicking glycopolymers were synthesized (n = 11), cultured in different concentrations (1%, 0.1%, and 0.01% w/v) with human corneal epithelial cells (HCE), and analyzed by various cytotoxicity/viability, morphology, and immunohistochemistry (IHC) assays. Six of the eleven glycopolymers were selected for further analysis after cytotoxicity/viability assays. We showed that the six selected glycopolymers had no cytotoxic effect on HCE cells in the 0.01% w/v concentration. They did not negatively affect cell viability and displayed both morphology and characteristic markers as untreated control cells. These polymers could be used in the future as mucin-mimicking semi-synthetic materials for lubrication and protection of the ocular surface.

Optical Quality and Visual Performance With Different Toric Contact Lens Designs.

To evaluate the optical quality of different toric contact lens (CL) designs and compare their on-eye visual correction performance. Twenty soft CL wearers aged 20 to 39 years were enrolled. Two daily disposable silicone-hydrogel toric CLs were tested: the "Eyelid Stabilized Design" (ESD-CL) and prism-ballast design (PB-CL); a spherical daily disposable silicone hydrogel CL (spherical CL) was used as a control. On-eye performance was compared for corrected distance visual acuity (CDVA), astigmatism, and ocular higher-order aberrations (HOAs); astigmatism and ocular HOAs were measured with a wavefront sensor. The subjective quality of vision, rated for "blurred vision" and "double vision," lens rotation, and fitting were also compared. The ESD-CLs, PB-CL, and no-CL provided better CDVA than spherical CL ( P <0.05). Compared with spherical CL and no CL, PB-CL and ESD-CLs caused significantly lesser astigmatism ( P <0.05). Coma was significantly lesser with ESD-CLs than that with PB-CL ( P <0.05); total HOAs did not differ among the four conditions. The subjective ratings for blurred and double vision were significantly lower with ESD-CLs than those with spherical CL ( P <0.05). Toric CLs provide a better CDVA than spherical CLs. However, differences in coma and subjective symptoms may occur because of the design of toric CLs.

Behaviour of hTERT in the tears of neophyte contact lens wearers during the sleep/wake cycle

PurposeTo investigate the behaviour of telomerase reverse transcriptase (hTERT) in the tears of healthy neophyte contact lenses-wearing individuals during the sleep/wake cycle. A subsequent aim was to investigate whether hTERT behaviour was associated with inflammatory mediators interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in tears. MethodsFlush tears were collected from 19 healthy, non-contact lens-wearing participants (11 males, 8 females, mean age 31.9 ± 5.7 years), before and during contact lens wear. Tears were collected at noon, before sleep and upon awakening and levels of hTERT, IL-6 and TNF-α, were determined using enzyme-linked immunosorbent assays (ELISA). ResultshTERT levels (median [interquartile range]) during contact lens wear were significantly higher before sleep (436.5 (263.9 – 697.7) ng/ml compared to the same time point without contact lenses (256.1 (0.0 – 590.9) ng/ml (p = 0.01). There was no difference between contact lens wear (851.3 [353.2 – 2109.9]) ng/ml, and no wear (1091.0 [492.3 – 3045.4]) ng/ml, upon awakening (p = 0.94). A significant increase was found upon awakening compared to before sleep, irrespective of the presence of a contact lens (p = 0.02). IL-6 and TNF-α levels in tears were below the limit of detection. ConclusionsThe study showed that hTERT increases after a contact lens is placed on the eye, but this change is small, compared to the impact of overnight eye closure. Taken together with the lack of responses of the inflammatory markers monitored at the same time points, this may suggest that hTERT can respond both to low-level stress stimuli acting on the ocular surface, and to situations where inflammation is a likely factor.

Presence of a soft contact lens during biometry

A case of an intraocular lens (IOL) power calculation error due to the presence of a soft contact lens (CL) is described. During preparation of a routine cataract surgery for a patient in the operating room, a soft CL was discovered on the patient’s surgical eye by the scrub nurse. Further, questioning revealed that the patient was a regular CL wearer and had possibly worn them during pre-operative biometric measurement, suggesting a potential error in his IOL calculation. Surgery was not performed, and the patient was given a CL holiday. Examination of the pre-operative B-scan ultrasound by the IOL Master700 confirmed the presence of the soft CL. Four weeks after the CL holiday, re-measurement of the surgical eye with the same biometric formula, lens factor and post-operative visual target revealed a +6.00 dioptre difference in the recommended lens implant. The patient underwent cataract extraction and IOL implantation with the correct IOL implant, with a good visual outcome. Presence of a CL during biometry causes a significant error in the IOL power calculation and should be identified preoperatively for this very common surgery.

Contact lens-related complications in austere conditions among military personnel: a systematic review

IntroductionMilitary service personnel are required to deploy to austere environments where they are exposed to harsh conditions. Many service personnel continue to wear contact lenses when deployed as they are...

Measuring quality of vision including negative dysphotopsia.

To adapt the Quality of Vision Questionnaire (QoV) for measuring negative dysphotopsia and to validate the original and modified versions in the Dutch population. The QoV was translated into Dutch according to standardized methodology. Negative dysphotopsia items were constructed based on focus group interviews, literature review and clinical data. The questionnaire was completed by 404 subjects, including contact lens wearers, patients with cataract and after cataract surgery (95.5% with a monofocal, 4.5% with a multifocal intraocular lens). Rasch analysis was applied for evaluation of reliability and validity of the original QoV and modified version, Negative Dysphotopsia QoV (ND-QoV). The frequency, severity and bothersome scales of the QoV and ND-QoV demonstrated good measurement precision, good fit statistics for all but one item, but significant mistargeting of more than one logit. Item estimations were stable across the study groups and scales were unidimensional with more than 50% of variance explained by the measurements. There was a positive correlation between questionnaire scores and best corrected visual acuity (r = 0.3, p < 0.01). The quality of vision measured by all three scales was significantly poorer (p < 0.01) in patients with negative dysphotopsia compared to asymptomatic pseudophakic patients. The Dutch version of the QoV questionnaire has shown good psychometric properties comparable to the native version as well as good reliability and validity. The addition of negative dysphotopsia items is a valuable modification for the reliable assessment of quality of vision in pseudophakic patients.

A Non-Invasive Circuit Breaker Arc Duration Measurement Method with Improved Robustness Based on Vibration–Sound Fusion and Convolutional Neural Network

Previous studies have shown that the contact wear estimation of circuit breakers can be based on the accumulative arc duration. However, one problem that remains unresolved is how to reliably measure the arc duration. Existing methods encounter difficulties in implementation and suffer from limited accuracy owing to the impact of the substation environment. To overcome these issues, this article presents a novel, non-invasive method for measuring arc duration that combines vibration–sound fusion and convolutional neural network. The proposed method demonstrates excellent performance, achieving errors below 0.1 ms under expected noise conditions and less than 1 ms in the presence of various forms of noise, transient interference, and even sensor failure. Its advantages include its ability to accurately measure arc duration and its robustness against noise and interference with unknown patterns and varying intensity as well as sensor failure. These features make it highly suitable for practical deployment in substation environments.

Changes in Expression in BMP2 and Two Closely Related Genes in Guinea Pig Retinal Pigment Epithelium during Induction and Recovery from Myopia.

We previously reported differential gene expression of the bone morphogenetic protein 2 (Bmp2) in guinea pig retinal pigment epithelium (RPE) after 1 day of hyperopic defocus, imposed with a negative contact lens (CLs). The study reported here sought to obtain insights into the temporal profiles of gene expression changes in Bmp2, as well as those of two closely related genes, the inhibitor of DNA binding 3 (Id3) and Noggin (Nog), both during myopia induction and when the CL treatment was terminated to allow recovery from induced myopia. To induce myopia, 2-week-old pigmented guinea pigs (New Zealand strain, n = 8) wore monocular -10 diopter (D) rigid gas-permeable (RGP) CLs for one week, while the other eye served as a control. Ocular measurements were made at baseline, 3 days, and 7 days after the initiation of CL wear, with treatment then being terminated and additional measurements being made after a further 3 days, 1 week, and 2 weeks. Spherical equivalent refractive errors (SERs), axial length (AL), choroidal thickness (ChT), and scleral thickness (ScT) data were collected using retinoscopy, optical biometry (Lenstar), and spectral domain optical coherence tomography (SD-OCT), respectively. RPE samples were collected from both eyes of the guinea pigs after either 1 day or 1 week of CL wear or 1 day or 2 weeks after its termination, and RNA was subsequently isolated and subjected to quantitative real-time PCR (qRT-PCR) analyses, targeting the Bmp2, Id3, and Nog genes. Mean interocular differences (treated-control) in AL and SER were significantly different from baseline after 3 and 7 days of CL wear, consistent with induced myopia (p < 0.001 for all cases). Termination of CL wear resulted in the normalization (i.e., recovery) of the ALs and SERs of the treated eyes within 7 days, and the earlier significant ChT thinning with CL wear (p = 0004, day 7) was replaced by rapid thickening, which remained significant on day 7 (p = 0.009) but had normalized by day 14. The ChT changes were much smaller in magnitude than the AL changes in both phases. Interocular differences in the ScT showed no significant changes. The Bmp2 and Id3 genes were both significantly downregulated with CL wear, after 1 day (p = 0.012 and 0.016) and 7 days (p = 0.002 and 0.005), while Bmp2 gene expression increased and Nog gene expression decreased after the termination of CL wear, albeit transiently, which was significant on 1 day (p = 0.004 and 0.04) but not 2 weeks later. No change in Id3 gene expression was observed over the latter period. Conclusions: The above patterns of myopia induction and recovery validate this negative RGP-CL model as an alternative to traditional spectacle lens models for guinea pigs. The defocus-driven, sign-dependent changes in the expression of the Bmp2 gene in guinea pig RPE are consistent with observations in chicks and demonstrate the important role of BMP2 in eye growth regulation.

Evaluation of recovery time of tear film function and ocular surface after discontinuing oral isotretinoin treatment for acne vulgaris : Correlation between oral isotretinoin and tear film function.

This study aimed to evaluate the recovery time of tear film function and ocular surface after discontinuing systemic isotretinoin treatment. This was a prospective, cross-sectional study. 34 eyes of 17 patients treated with low- dose oral isotretinoin (< 0.5mg/kg/day) were enrolled. The modified OSDI score, tear break-up time, Schirmer test, and corneal staining were performed in all patients at baseline, during the course of treatment and after withdrawing treatment every two weeks until the result returned to baseline. Tear breakup time appeared to be the most sensitive and changed significantly at 2weeks after starting treatment (p < 0.001) and returned to baseline at 4weeks after withdrawal from treatment (p < 0.001). The Schirmer test results significantly decreased at 6weeks and returned to baseline at 4weeks after withdrawal from treatment (p < 0.001). OSDI scores were significantly changed at 6weeks after treatment (81.8%) and returned to baseline at 2weeks (54.5%) after withdrawal from treatment. No significant change was found in the MGD. Corneal staining was significantly positive 90.9% 6weeks after starting treatment and returned to baseline 6weeks after withdrawal from treatment (p < 0.001). Dry eye disease can return to baseline levels after treatment withdrawal. At least 6weeks later, they could wear contact lenses again, and it was useful to prepare all patients requiring further ocular surgery.

Effect of surface micro-grooved textures in suppressing stick-slip vibration in high-speed train brake systems

Efficient strategies for controlling low-frequency stick-slip vibrations during high-speed train braking are crucial for safe operations. This study applies surface texturing with micro-grooved textures on friction blocks and conducts tests to validate their suppression effect on stick-slip vibrations. Vibration analysis indicates that micro-grooved textures effectively mitigate system vibration intensity, decreasing amplitude and stick time as texture area density increases within a certain range. Further analysis reveals that these textures improve the contact behavior at the disc-block interface, reducing eccentric wear angle and contact plateau size. Changes in contact characteristics result in variations in the vibration response, thereby suppressing stick-slip vibrations. The research establishes a solid theoretical foundation and offers practical recommendations for reducing stick-slip vibrations in high-speed train brake systems.

Experimental investigation on rolling contact wear in grease lubricated spherical roller bearings using microcomputed tomography (μCT)

This study presents a novel and non-destructive method for quantitatively analysing grease lubricated bearing wear by using X-ray microcomputed tomography (μCT). The efficacy of μCT to measure rolling contact wear via wear debris analysis was demonstrated, as was quantifying grease contamination and wear debris identification. Test rig experiments of grease lubricated spherical roller bearings, were performed to simulate rolling contact wear. Six grease samples were collected from two bearings at three different intervals to investigate wear progression. Results showed μCT measured wear volume increased exponentially with increasing bearing operation times. Grease cleanliness (particle counts per ml) worsened nonlinearly due to the exponential growth of wear debris over longer bearing operational times. Comparing the conventional ISO281 bearing assembly and operating condition assessment, a particle-count based method via μCT analysis provided a less subjective and dynamic assessment for quantifying grease contamination. Grease contamination was found to increase with longer operational timeframes due to the combination of wear debris growth and decreased lubrication film thickness. Finally, laminar, chunk and spherical wear particles, associated with rolling contact wear, were identified by the morphometric parameters measured by μCT. This study highlights the potential of μCT as a wear monitoring and grease quality assessment technique for railway bearing applications.

Effects of Crosswind on Pantograph–Catenary Wear Using Nonlinear Multibody System Dynamic Algorithms

In this study, a multibody system (MBS) computational framework is developed to determine the exact location of the contact point and wear prediction resulting from the pantograph–catenary interaction. The railroad vehicle models in the MBS computational framework comprise rigid-body railroad vehicles, rigid-body pantograph systems, and flexible catenary systems. To avoid incremental rotation, the nonlinear finite element absolute nodal coordinate formulation is used to model a flexible catenary system in the MBS computational framework. To avoid co-simulation processes, the rigid-body railroad vehicle and the pantograph and flexible catenary systems were integrated into the MBS algorithms. The pantograph–catenary interaction is modeled using an elastic contact formulation developed to include the effect of pantograph–catenary separation and sliding contact. The proposed MBS approach evaluates the location of the contact point, contact force, and normal wear rate (NWR) from the mechanical and electrical contributions. This investigation considers the vibration caused by a crosswind scenario and determines the numerical result in the case of a steady crosswind scenario. The steady crosswind scenario contains the advantage of pantograph–catenary aerodynamic design, and the vibration of the catenary system remains significant after the excitation of a steady crosswind. In the case of a steady crosswind, the higher value of the steady crosswind effect significantly increases the mean contact force and the NWR from the mechanical contribution. After crosswind load disturbances, the mean contact force decreases, but the standard deviation of the contact force increases. Therefore, the NWR from the electrical contribution increases significantly. However, the total NWR increases with the crosswind velocity.

The discrete wavelet transform based iris recognition for eyes with non-cosmetic contact lens

Iris recognition has been used as one of the biometric systems for user authentication, identification, and verification for quite some time. The basis of an iris recognition lies on the matching algorithm, which requires similarities of the iris data in the database with the captured one. In addition, nowadays using non-cosmetic or prescribed contact lenses becomes more popular and more preferred choice of many people, which makes the number of contact lens wearers significantly increases. These eyes with contact lenses add more complexity to the iris recognition process, since it can disturb the matching process which then affect the performance of the system. This situation has motivated this study to propose an iris recognition system that works for eyes with lenses. The proposed iris recognition system for eyes wearing non-cosmetic contact lenses was developed using circular hough transform (CHT) in the preprocessing phase for iris localization and discrete wavelet transform (DWT) for feature extraction. Experiments conducted on the proposed system has shown promising results with good accuracy of 0.95 for eyes with no contact lens and 0.8 for eyes with non-cosmetic lenses. The findings also suggested the importance of the iris localization process to the performance of the recognition system.

Ocular Surface Homeostasis After Scleral Lens Usage.

The aim of this prospective study is to examine the effects of 5 hours of well-fitted, mini-scleral contact lens (mini-SL) wear on the tear film cytokine expression in healthy eyes. Twenty-three healthy participants were included in the study. One eye of each participant was selected at random, and a mini-SL measuring 16.5 mm in diameter was fitted by an experienced contact lens specialist. The contact lens remained in place for 5 hours. Precorneal tear fluid was collected using capillary tubes at three different time points: baseline before SL insertion (T0), after 5 hours of SL wear (T1), and 3 hours after SL removal (T2). The concentration of 40 inflammatory cytokines at the three different time points was determined using multiplex bead assay. Mini-scleral lens wear did not result in significant changes in the cytokine-to-protein ratio after 5 hours of wear on a healthy eye. Although a well-fitted mini-SL reduces the rate at which the precorneal tear film is refreshed, 5 hours of lens wear did not appear to significantly affect the tears cytokine-to-protein ratio, suggesting that scleral lenses have minimal impact on corneal cytokine expression.

Comparison of chemical composition and wear of iron and nickel aluminide coatings applied by plasma spraying

Given such properties as wear resistance, corrosion resistance, heat resistance, contact and cyclic strength, iron and nickel aluminides can be used as coatings in friction pairs for various purposes. The object of research is the process of obtaining plasma-sprayed coatings from powders based on iron and nickel aluminides. The task of research is the determination and comparison of the structure, chemical composition, and wear resistance of coatings from powders of iron aluminide and nickel aluminide, obtained by the method of atmospheric plasma spraying. To reduce the oxidation of powders during spraying, the conditions for generating a laminar plasma jet were created. Such conditions were provided by the specially developed structure of the electric arc plasma gun and the operating parameters of coating spraying. As a result of the correct choice of spraying modes, completely melted splats were formed during the collision of powder particles with the surface. The resulting coatings had a layered microstructure with microcracks and peeling. The porosity and characteristics of the delamination of the coatings depend on both the modes and the spraying technology. Tribological tests of the coatings were carried out under conditions of dry metal-on-metal sliding friction in a pair with high-speed steel. It is shown that the wear of nickel aluminide coatings under these conditions is 2–2.5 times lower than that of iron aluminide coatings. The coefficient of friction of iron aluminide coatings is slightly lower than that of nickel aluminide coatings. The wear of samples made of 30CrMnSi steel is 3–4 times higher than samples with coatings. The difference in the wear of the coatings is explained by the more intense oxidation of iron aluminide in the friction process. Conclusions were drawn regarding the possibility of using the investigated coatings in various friction pairs of structural elements, in particular in the automotive industry