Tribochemical Activation Research Articles

Tribological Analysis of Steels in Fuel Environments: Impact of Alloy Content and Hardness

The performance and durability of high-pressure fuel systems in combustion engines are critical for consistent operation under extreme conditions. High-pressure fuel systems are traditionally lubricated with fuel that is compressed and delivered to the combustion chamber. However, lubrication with fuel presents significant challenges in these systems when used with low-viscosity fuels, leading to increased wear rates, especially in reciprocating contacts. This study delved into the tribological performance of steels of varying alloy content (annealed and hardened variants of AISI-52100, CF2, and D2) against alumina and hard 52100 counterbody materials in ethanol and decane environments. Friction and wear behaviors were evaluated, highlighting the influence of material interactions and environmental factors. Elastohydrodynamic lubrication analysis of the tested systems indicated that ethanol and decane form lubricating films of nanometer-scale thickness, confirming the boundary lubrication regimes of the performed tests. In summary, the tribological behavior trends were similar for alumina and 52100 counterbodies. Even though soft 52100 steel demonstrated low friction, its wear was the largest for both tested environments and counterface materials. Among all the tested materials, hard D2 experienced the lowest wear. 52100 and D2 steels showed opposite friction change behavior when comparing hard and soft samples, with lower friction observed for softer 52100 steel and harder D2 steel. Meanwhile, the wear was lower for harder candidates than for softer ones independent of the environment and counterbody material. Raman spectroscopy analysis of the formed wear tracks indicated the formation of carbon films with larger intensities of characteristic carbon peaks observed for more wear-resistant materials. These results suggest the synergistic effect of hardness and tribochemical activity in reducing the wear of materials.

The effect of abrasive additives on the tribotechnical properties of lubricants for the wheel–rail system

The paper studies the polishing power of a tribochemically active abrasive material based on a solid solution of iron and aluminum oxides, as well as a solid solution of aluminum and iron oxides modified by zirconium oxide and yttrium oxide additives, and the tribotechnical properties of a lubricant doped with these abrasive materials. The modified Al2O3·Fe2O3·ZrO2·Y2O3 powders prove to have an essentially higher polishing power producing a considerably lower surface roughness than that of the unmodified Al2O3·Fe2O3 powder. By varying the content of the modifying oxides, one can change the tribochemical activity of the abrasive powder and select the best composition depending on the material to be polished. The addition of these abrasive powders is shown to have an essential effect on the tribotechnical properties of the lubricant for the wheel–rail contact. The laboratory testing of the lubricant compositions suggests their effective applicability to the wheel–rail contact.

Comparison of graphene as an oil additive with conventional automotive additives for the lubrication of steel and DLC-coated surfaces

The present work is focused on comparing the tribological behaviour of graphene platelets and commercially available automotive additive package, combined with glyceryl isostearate (GIS) as a friction modifier. The investigation was performed with steel/steel and DLC/DLC contacts, at 25 °C and 100 °C, in all lubrication regimes and by considering the running-in effect. Under all the investigated conditions the graphene platelets provided the lowest friction in the ML and BL regimes. This is the result of forming graphene-based tribofilms which, unlike for the other tested lubricants, is relatively insensitive to temperature, tribochemical activation and the conditions before or after the running-in. By combined the use of graphene platelets and conventional additives some interactions in their tribological behaviour were also observed.

Double-layered core–shell heterostructures of mSiO2@CdS@CeO2 abrasive systems toward photochemical mechanical polishing (PCMP) applications

Photochemical mechanical polishing (PCMP) technique, involved the cooperation of light-driven surface modification and force-induced material removal, is expected to be a clean, high-quality, and high-efficiency processing method. Herein, mSiO2@CdS@CeO2 hybrids with mesoporous cores and double-layered core–shell heterostructures were constructed through a three-step strategy and utilized as novel abrasive systems towards PCMP applications. Morphological, structural, and optical characterizations were systematically performed to investigate the correlation between components and polishing performances of the proposed abrasive systems. The created CdS–CeO2 heterojunction contributed to the efficient separation of photogenerated charge carriers and the production of highly reactive oxygen species, thus promoting the formation of photochemically reacted layers. The tribochemical activity and material removal enhancements might be attributed to the enrichments of trivalent cerium and oxygen vacancy in CeO2 layer after introducing CdS intermediate layer. Moreover, the involved mesoporous SiO2 cores were responsible for the optimized abrasive–wafer interface contacts and the eliminated surface damages. As expected, the proposed abrasive system enabled the nearly scratch-free and atomically planarized surfaces with angstrom-level finish (∼0.14 nm Ra, ∼0.18 nm Rq, ∼0.21 nm Rz), and simultaneously offered a ca. 63.8% of removal efficiency enhancement in PCMP compared to conventional CMP.

Monitoring of friction node surfaces in the context of their physico-chemical interactions with lubricating media of different surface activity

The article deals with tribochemical influence of the surface activity of biosynthetic oils on the operational efficiency and reliability of lubricated friction nodes under the critical conditions. It is proved that the oil surface activity is caused by the structure and properties of their molecules and interactions with steel surfaces. Evaluating criteria of oil tribochemical activity influence on the steel surface modification has been studied. The significant influence of biooils on the steel surface nanolayer phase transformations, friction and steel wearing is claimed. It has been established that the effect of the steel crystal structure deformation and strengthening its surface depends on activity of composition of lubricant. It is proved that biooils lead to improved friction and wear indicators of lubricated samples. X-structural analysis of the steel surfaces showed that during friction the austenite is destroyed and ferrite is formed. Penetration in the lubricated steel nanolayers shows increasing the ferrite and decreasing the austenite content, that cases reducing the deformation degree of metal crystals, which leads to the strengthening of its surface under the plasticized layer and to decreasing the level of friction and wear due to the formed intersurface servitotribopolymer film, which is stable under critical friction.

ENSURING THE EFFICIENT OPERATION OF FRICTION UNITS IN THE CONTEXT OF SELECTING FUNCTIONALLY HIGH QUALITY OILS

The article reflects certain applied aspects of a new direction of energy — biosynthetic energy sources, such as bio-oils obtained from technical oils. In particular, there are considered results of the research of the influence of such a characteristic factor of base oils and, first of all, bio-oils as their surface activity on energy efficiency and reliability of operation of friction units lubricated by them under the conditions of the boundary regime of friction. It is proved that the surface activity of oils as an indicator of their functional quality is due to the peculiarities of the structure and properties of their molecules, the energy fields of which evoke certain tribochemical interactions with triboactivated nano-surfaces of friction steels. Separate provisions for evaluating the effect of the tribochemical activity of oils on the process of modifying the steel surfaces of functioning friction units have been formed. The essence of X-ray examination of the influence of lubricating media on the condition of the steel surface by the method of a sliding X-ray beam, analyzing the surface layers with a depth of 0.5–7 mkm. The effect of significant influence of bio-oils obtained from oils on the phase transformations of the structure and properties of the steel surface during tribe tests of samples on friction and wear is revealed. It is established that the effect of obtaining the crystal structure of steel with surface hardening under the deformed layer depends on the tribochemical activity of the proposed three lubricating compositions, which are characterized by the algorithmic growth of such activity. It is proved that the tribochemical activity of bio-oils (in compositions 2 and 3, estimated by the intensity of phase transformations in the surface layers (the effect of Rebinder PO), leads, in turn, to improved friction and wear of lubricated samples compared to the composition 1 low triboactivity. X-structural surfaces analysis of the samples of steel 45 in the initial state and after testing in the media of each of the compositions showed that in the friction processes there is a destruction of the structure of austenite with the release of α-phase (ferrite). It is shown that the intensity of such modification of steel surfaces is progressively amplified in samples lubricated with compositions in accordance with their increasing triboactivity. It was found that with the penetration into the surface layers of steel (from 0.5 to 7 mkm), lubricated with bio-oils of the samples after their tribometer tests, the amount of ferrite increases and the content of austenite decreases. This reduces the deformability of the structure of metal crystals, which leads to the strengthening of its surface under its plasticized layer, and hence the reduction of friction and wear due to the formed intersurface servito-tribopolymer film, resistant to friction. Bibl. 12, Fig. 5, Tab. 3.

In-situ instrumentation to observe transient tribological effects in high sliding speed unlubricated contacts

Non-invasive and high data rate instrumentation methods are critically needed for in-situ monitoring and analysis of transient effects of high sliding speed dry mechanical contacts of gears and bearings, where increases in temperature and changes in surface chemistry control the tribological response. This study examines some of the approaches on an example of an unlubricated contact of a silicon nitride ball on a steel disk operating in humid air at about 1.5 GPa contact pressure with variable high sliding speeds (ranging from 1 to 16 m/s), while using correlated in-situ optical imaging and thermography to aid in the analysis of changes in tribological response. In-situ optical imaging of wear tracks with quantified color analysis was used to detect the increased tribochemical activity, and thermography helped to correlate this tribochemical activity with thermal effects induced by the frictional heating. The post-experiment analysis with scanning electron microscopy and energy dispersive spectroscopy elemental mapping confirmed the development of the oxide based tribofilm correlating to the changes in the optical imaging and thermography. The results indicate that both employed in-situ methods were effective in the measurement of signals that were related to changes in the mechanical or tribochemical behavior of high speed sliding contacts, linked to transitions in the coefficient of friction from a high value to low, and accompanied by the transition from oxidative wear to the formation of a complex tribofilm at speeds above 4.5 m/s. The discussed instrumentation methods and data analysis approaches enhance the in-situ capability for evaluating transient tribological effects at high sliding speeds and contact loads.

Iron‐Nanoparticle Driven Tribochemistry Leading to Superlubric Sliding Interfaces

AbstractAny moving mechanical system consisting of sliding/rolling or rotating interfaces experiences friction and wear. High contact pressure and shear during relative movement of the sliding interfaces in the presence of lubricants often lead to interesting tribochemical activity at nanoscale, which then greatly influences the tribological performance of the mechanical systems at macroscale. Understanding these tribochemical interactions and to be able to manipulate them will be a key in designing smart solid lubricants that can self‐generate at the sliding interfaces and thus help in drastically improving the overall efficiency of these moving mechanical systems. In this study, it is demonstrated that solid lubricant consisting graphene mixed with iron nanoparticles (NPs) under high contact pressures at the sliding interface undergo tribochemical reaction leading to the formation of onion‐like‐carbon nanostructures (OLCs). Combining with atomistic molecular dynamic simulations, the tribochemical mechanism of formation of OLC with pure iron NPs and how that depends sensitively on the core–shell chemistry of the nanoparticle is elucidated. Interestingly, the formed OLCs lead to the near‐zero friction (superlubricity) during sliding in dry conditions, thus demonstrating great potential to be used as a solid lubricant for various tribological applications.

Composite particles with dendritic mesoporous-silica cores and nano-sized CeO2 shells and their application to abrasives in chemical mechanical polishing

The structure and mechanical/chemical performance of particle abrasives in polishing slurries play an important role in chemical mechanical polishing (CMP) processes. In the present paper, the CeO2-based novel abrasive particles containing dendritic mesoporous silica (D-mSiO2) cores and nano-sized CeO2 shells present potential applications in high-efficiency and defect-free CMP, resulting from their special mechanical and/or chemical characteristics. The D-mSiO2 cores of composites were prepared via a modified biphase stratification approach, and the nano-sized CeO2 particles were coated via an in-situ chemical precipitation technique. The composition and structure of as-synthesized samples were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy, and nitrogen sorption-desorption measurements. The effect of the core category for the CeO2-based composite particles on oxide-CMP performance was evaluated in termers of material removal rate (MRR) and root-mean-square (RMS) roughness (determined by atomic force microscopy). Experimental results indicated that the as-obtained D-mSiO2/CeO2 abrasives exhibited a comparable RMS roughness (0.18 ± 0.02 nm) with respect to the polystyrene/CeO2 abrasives (0.15 ± 0.02 nm) with polymer cores. However, the MRR of the D-mSiO2/CeO2 abrasives (85 nm/min) was three times larger than that of the PS/CeO2 abrasives (26 nm/min). The enhanced polishing efficiency may be attributed to the differences of the mechanical behavior and surface atom structure of the nano-sized CeO2 particles of the composites after treatment by high-temperature calcination. The improved oxide-CMP behavior of D-mSiO2/CeO2 composite particles may result from the spring-like effect coming from the elastic component of the cores, and the enhanced surface hardness and tribo-chemical activity of CeO2 particles in the shells.

Impact of α-C2SH calcination temperature on the mineral composition and heat flow of the products

In this work, the peculiarities of the formation of α-C2SH using natural raw materials (calcined limestone and carbonated opoka) as well as the impact of thermal activation parameters to the formation of hydraulically active C2S polymorphs, their mineral composition, and hydraulic activity are presented. Hydrothermal syntheses were carried out at the temperatures of 180 and 200 °C for 2, 4, 8, 12, 24, and 72 h from mixtures with molar ratio CaO/SiO2 = 2.0. XRD, DTA, and DSC analyses showed that opoka, calcined at 775 °C, is a suitable material for the synthesis of α-C2SH. After tribochemical activation (950 rpm, 5 min), α-C2SH and its mixture with quartz (1:1 by mass) were treated thermally at the temperatures ranging between 450 and 1000 °C. At dehydration temperature (450 °C), α-C2SH forms the most active phase—x-C2S. By increasing the temperature, the other active phases such as β-C2S (600 °C) and α′L-C2S (800 °C) are formed. Unfortunately, they coexist with inactive γ-C2S. Thus, it is possible to avoid the last phase formation by grinding α-C2SH with quartz sand. Thermally activated α-C2SH mixture with quartz sand at the temperature of 450–500 °C is suitable for binder material manufacture: during the main hydration reaction, heat flow reached 0.0017–0.0018 W g−1, and total heat release after 72 h of hydration was 61.30–67.52 J g−1.

Reaction kinetics of equiatomic Fe–Mo solid solutions obtained by mechanical alloying: an X-ray diffraction and Mössbauer spectroscopy study

The reaction kinetics of equiatomic Fe–Mo solid solutions produced by mechanical alloying were studied by X-ray diffraction and Mossbauer spectroscopy. The materials were milled with velocities of rotation of 400 and 500 rpm for several milling times to obtain samples of various reaction stages. The X-ray diffraction patterns showed the presence of two bcc phases, corresponding to metallic Fe and Mo, in all samples. Analysis of these diffractograms indicated diffusion of Mo within the Fe matrix and diffusion of Fe within the Mo matrix, as a result of the milling process. While the X-ray diffraction technique did not allow for the identification of a crystallographic phase being clearly transformed, making it difficult to study the reaction kinetics, using Mossbauer spectroscopy, it was possible to identify two magnetic phases that suffer transformation during the course of milling: a ferromagnetic sextet corresponding to metallic Fe and a paramagnetic doublet corresponding to Fe atoms with a majority of Mo neighbors (metallic Mo does not possess a magnetic moment). Both magnetic phases may be present in the bcc Fe matrix or the bcc Mo matrix. The transformation kinetics of the sextet were studied using a method based on a local description of phase volume transformation, depicted by the tribochemical activity parameter. The results were compared to published work on the application of this method to Fe–Cu and Fe–N systems. A behavior similar to that of Fe–N was observed, which, similar to the Fe–Mo system and as opposed to the Fe–Cu system, possesses a positive enthalpy of mixing.

Synthesis of low-energy cement based on α-C2SH

In this study, parameters of α-C2SH synthesis from limestone and quartz sand were determined and compressive strength values of the hydraulic cementitious binder, manufactured on its basis, were established. The results show that slow hydrothermal reactions in the calcium oxide–quartz–water system can be intensified using sodium oxide additive. In this case, α-C2SH was already the dominant compound in the product after 8 h of hydrothermal synthesis at 200°C in stirred suspensions. It was found that tribochemical activation must be combined with thermal treatment in order to obtain a hydraulically active cementitious binder from the mixture of synthesised α-C2SH and quartz sand. The heat flow value of such binding material during its main hydration reaction varied from 0·0019 W/g to 0·0028 W/g when the temperature of the thermal treatment was increased from 400°C to 450°C. Strength measurements showed that the addition of sieved quartz sand increased the compressive strength of the mortars, compared with a pure hydraulic cementitious binder, from 10·3 MPa to 13·5 MPa after 3 d, from 12·9 MPa to 16·7 MPa after 7 d and from 19·4 MPa to 22·5 MPa after 28 d of hydration.

Quantitative thermal analysis of α-C2SH as a precursor for low-energy cements

In this work, a combined method of using DSC, TG and XRD analysis in order to determine an amount of decomposed α-C2SH in its tribochemically activated mixture with quartz is presented. Furthermore, the influence of the grinding on the phase transition and heat flow during the hydration of this mixture is determined. The results showed that the product in which α-C2SH prevails is obtained after 12 h of the hydrothermal synthesis at 200 °C in stirred (50 rpm) suspensions. The purification of mentioned product using distilled water (water/solid = 500) for 5 min is enough to eliminate remaining Ca(OH)2. The stability of α-C2SH during the purification was confirmed using DSC and XRD analysis. A strong correlation between heat absorption values of the α-C2SH decomposition at 470 °C and its quantity in the mixture with quartz was noticed (R 2 = 0.9929). According to the plotted calibration curve, the amount of decomposed α-C2SH during the tribochemical activation was determined: within the first minute, it reaches 32.28 % and gradually increases to 48.73 % after 20 min. During the decomposition of α-C2SH, the semi-crystalline calcium silicate hydrates form, which recrystallize to wollastonite at 850 °C; meanwhile, the remaining α-C2SH transforms to larnite. The complex tribochemical and thermal activation of α-C2SH–quartz mixture leads to a vivid increment of its hydraulic activity: the heat flow of the main hydration reaction and the total heat values reached 3.1 mW g−1 and 104.48 J g−1, respectively.

Heat flow and strength properties of perspective hydraulic binder material

In this work, the results of preparing a novel hydraulic binder material on α-C2SH basis using both chemically pure and natural raw materials are presented, as well as hydration and strength properties of such binders are described. α-C2SH was hydrothermally synthesized at 200 °C for 8 h from reagents (CaO, SiO2·H2O) and for 4 h from natural rocks (decalcinated chalk marl, opoka). DSC and XRD analysis showed that remaining portlandite and part of α-C2SH decompose during 5 min of intensive tribochemical activation of the synthesis products and quartz mixture. Unfortunately, according to TG data, water released from these compounds remains in the sample. Applying different types of mills as well as the adding water adsorbents (CaO, CaCl2 and BaO) has no effect on the hydraulic activity of the binder: The results of microcalorimetric analysis indicate that heat flow values of the main hydration reactions decreased in all cases. Most suitable way of removing water from the samples is low-temperature thermal treatment at 450 °C. Milled α-C2SH–quartz mixture exhibited good binding properties after burning mixtures at this temperature. The mortar with the highest compressive and bending strength values (20.43 and 5.17 MPa after 28 days of hydration) was obtained using mixture which consisted of 25 % (by mass) synthesis product (obtained from hydrothermal synthesis of opoka and chalk marl), 25 % together with α-C2SH-milled quartz sand (during the tribochemical activation) and 50 % standard sand.

Tribochemical Formation of Sulphide Tribofilms from a Ti–C–S Coating Sliding Against Different Counter Surfaces

Tribochemically active Ti–C–S coatings are nanocomposite coatings containing a S-doped titanium carbide, from which S can be released in a tribological contact. This work studies tribochemical reactions between a Ti–C–S coating and various counter surface materials, and their effect on the tribological performance. Tribological tests were performed in a ball-on-disc set-up, using balls of five different materials as sliding partners for the coating: 100Cr6 steel, pure W, WC, 316-L steel and Al2O3. For W balls, a WS2 tribofilm was formed, leading to low friction (down to µ = 0.06). Furthermore, increasing normal load on the W balls was found to lead to a strong decrease in µ and earlier formation of the low-friction WS2 tribofilm. Similar WS2 and MoS2 tribofilms were, however, not formed from WC- and Mo-containing 316-L balls. The performance when using WC and Al2O3 balls was significantly worse than for the two steel balls. It is suggested that this is due to sulphide formation from Fe, analogous to formation of anti-seizure tribofilms from S-containing extreme pressure additives and steel surfaces. The tribochemical activity of Ti–C–S coatings, with the possibility of S release, is thus beneficial not only for pure W counter surfaces, but also for Fe-based sliding partners.

Tribochemical and thermal activation of α-c2s hydrate as precursor for cementitious binders

In this paper, the favorable chemical composition of alternative hydraulic cementitious binder (HCB) consisting of synthetic α-C2S hydrate and quartz, as well as the impact of tribochemical—thermal treatment on HCB properties was determined. Hydraulic cementitious binder was prepared by mixing synthetic α-C2S hydrate and quartz sand (the ratio was equal to 1:1 by mass), homogenizing in a homogenizer at 34 rpm for 30 min. Tribochemical activation was carried out in vibratory disk mill at 950 rpm for 2, 5, 10, and 20 min. It was estimated that the tribochemical activation affects the properties of HCB because a higher fineness provides a greater surface area to be wetted, and also results in an acceleration of the reaction between HCB and water. It was determined that the favorable tribochemical activation time for α-C2S hydrate is 5 min. Meanwhile, the investigation of the influence of quartz quantity in composition showed that at least 50 % of it is essential. Also, these studies showed that coupled application of tribochemical and thermal activation helps to create HCB samples with higher reactivity. In addition, it was determined that the best conditions are when α-C2S hydrate and quartz sand ratio is 1:1, tribochemical activation time in vibratory disk mill at 950 rpm: 5 min, thermal activation temperature: 450 °C, duration: 30 min. HCB made under these conditions has 3.7 m Wg−1 of heat flow and is similar to Portland cement.

Thermochemistry of triboactivated natural and NH4-exchanged clinoptilolite mixed with Tunisian apatite

Abstract Mechanical tribo- and thermo-chemical methods applied for remodeling phosphate raw materials manifest a number of advantages over the conventional technologies. They are related to the reduction of soil contamination and minimization of the released gas emissions in the environment and generate solid wastes. In this work, natural and NH4-exchanged clinoptilolite are used for increasing the transition of P2O5 into assimilated by plants form during tribochemical activation (TCA). Better nutrients assimilation as well as green production could be achieved by applying such a treatment based on the ion-exchange reactions taking place in the soil. The occurring upon TCA structural changes and phase transformations of the used Tunisian phosphorite, natural and NH4-exchanged clinoptilolite as well as their mixtures are investigated by means of X-ray powder diffraction, IR spectroscopy, and thermal analysis. The thermal method gives evidence for solid phase reactions and increased reactivity as a result o...

NON-EQUILIBRIUM SELF‐ORGANIZATION OF STEEL‐BRONZE TRIBOSYSTEM ON THE BASIS OF THE ACOUSTIC EMISSION METHOD

Directed copper to steel mass transfer caused by tribochemical activation and heat flow optimisation is researched in this article. It allows the application of selective transfer effect for contact surfaces of tribosystems without clad metal alloy injection into the lubricant environment. Santrauka Darbe pateiktas kryptiniu vario mases mainu tyrimas, kai varis perne šamas link plieno ne tik del tribocheminio aktyvinimo, bet ir del šilumos srauto oprtimizavimo. Tai leidžia pritaikyti “rinktiniu mainu” efekta nepanardinant tribosistemos kontakto paviršiaus medžiagos i aliejiniu mišiniu, skirtu metalo padengimui, terpe.

The Wear Resistance of HVOF Sprayed Composite Coatings

The aim of the study was to determine the interactions between standard antiwear zinc dialkyldithiophosphate (ZDTP)-type additives and composite coatings containing hard phases of Al2O3, SiC, and TiN in the nickel matrix. The analysis was conducted for selected ceramic materials with different structures and different tribological behavior of ionic, covalent, and metallic bonds. The composite coatings were deposited on C45 steel using the high-velocity oxygen-fuel (HVOF) process. This process efficiently uses high kinetic energy and controlled thermal output to produce dense, low porosity coatings with highly predictable chemistries that are homogeneous in structure. The coatings can operate under harsh service conditions, because they are characterized by higher durability and higher wear and corrosion resistance. It was necessary to determine the interactions between the ZDTP-type antiwear additives (zinc dialkyldithiophosphates) and the coatings. The tribological properties of nickel and nickel-based composite coatings were examined by means of a T-01 M tester functioning in the ball-on-disc configuration during technically dry friction and boundary lubricated friction with lubricants containing 1% ZDTP. The comparative analysis confirmed different tribochemical activity and, accordingly, different tribological effectiveness of the nickel and nickel-based composite coatings during friction.

Abrasive properties of aluminum iron oxide nanoparticles

Aluminum iron oxide nanoparticles have been prepared by heat-treating ammonium hydroxycarbonate complexes with the general formula NH4Al2Fe(OH)5(CO3) · nH2O and have been characterized by X-ray diffraction, IR spectroscopy, differential thermal analysis, scanning electron microscopy, and particle size analysis. The mixed oxide α-Al2 − x Fe x O3 with x = 0.30−0.37 prepared from hydroxy complexes ensures surface roughness values R a = 0.005−0.02 µm in polishing of the ShKh15 quenched steel with an austenite/martensite structure and offers high abrasion rate owing to its enhanced tribochemical activity and the presence of particles in the size range 1–10 nm.