Abrasive Environment Research Articles

All-day superhydrophobic photo-thermal and electro-thermal icephobic surfaces based on ZrN/MoSe2 composite

Ice formation on equipment and infrastructure surfaces can lead to severe damage and operational disruptions, necessitating advancements in passive anti-icing technologies to enhance de-icing efficiency. Superhydrophobic materials offer notable improvements, such as minimal water affinity and reduced ice adhesion. However, their practical application is hindered by limited durability and vulnerability to cold and humid conditions. This study presents the development of a micro-nanostructured ZrN/MoSe2 photo-electrothermal superhydrophobic composite coating, which exhibits physical and chemical self-cleaning capabilities both day and night. This innovative coating rapidly heats due to the combined effects of solar absorption and Joule heating. It reaches 89.4 °C in 600 s under simulated sunlight and 81 °C with a 15 V electrical input in 300 s. With a contact angle exceeding 155°, it demonstrates superior self-cleaning abilities. Moreover, the coating retains its exceptional anti-icing and de-icing properties even after exposure to mechanical stress, abrasion, and harsh chemical environments. It can rapidly melt ice from surfaces in just 66 s at −20 °C under one sun, achieving a 76 % efficiency in photo-thermal de-icing. Electro-thermal de-icing tests reveal that the coating can melt ice in 55 s with an 87 % efficiency. These promising features, attributed to the unique properties of ZrN nanoparticles and MoSe2 nanosheets, significantly provide substantial advancements in superhydrophobic coating technologies. They offer the potential for large-scale production and enhanced performance in ice management.

Effects of nanoceramic particle size and content on the wear resistance of micro-arc oxidation coatings for 2A12 aluminum alloy

The 2A12 aluminum alloy, renowned for its exceptional mechanical properties, encounters significant limitations in applications involving abrasive environments or frequent contact with other surfaces due to its inadequate wear resistance. This shortcoming substantially reduces the service life of components and escalate maintenance costs, highlighting the urgent need for advanced surface modification techniques. This study meticulously investigates the influence of nanoceramic particle size and content on the wear resistance of micro-arc oxidation (MAO) coatings, a surface modification technique renowned for forming dense, adherent ceramic layers on aluminum alloys. The systematic experimentation revealed that the incorporation of 150 nm α-Al2O3 nanoparticles into the MAO matrix achieves an optimal dispersion, leading to a substantial enhancement in wear resistance. The sample with a 5 g/L concentration of 150 nm α-Al2O3 nanoparticles doping in the MAO electrolyte demonstrated the lowest mass loss, underscoring its enhanced wear resistance. The enhanced microstructure, enriched with hard ceramic phases such as α-Al2O3 and mullite, plays a pivotal role in withstanding wear. Moreover, this study identified that an optimal balance of surface roughness and coating thickness is essential for achieving enhanced wear resistance. The findings of this research provide a strategy for the design of wear-resistant coatings tailored for high-performance applications across aerospace, automotive, and general engineering industries. By optimizing the particle size and concentration in MAO coatings, this study paves the way for the development of durable materials capable of thriving in demanding environments, thereby extending the service life and reducing maintenance requirements of components.

Investigating the erosive wear characteristics of AISI 420 martensitic stainless steel after surface hardening by boriding

Erosive wear degrades industrial components, causing surface deterioration and material loss. Understanding and mitigating this wear enhances component longevity and efficiency. Little research has been conducted to investigate the influence of particle angle, speed, and concentration on boronized surfaces. Therefore, in this study, the erosive wear behaviors of raw and boronized AISI 420 martensitic stainless steels were investigated. The samples were subjected to erosive wear testing using SiO2 abrasive particles with impact velocities of 2, 4, and 6 m/s, impact angles of 30°, 60°, and 90°, and concentration values of 5%, 10%, and 15% by weight in an abrasive sand slurry environment. Experimental runs were designed using the Taguchi L9 method. The wear test results were analyzed in terms of mass loss, surface roughness, and temperature change of the boronized and raw AISI 420 samples before and after the test. The results showed that the impact speed and concentration were statistically significant parameters compared with the impact angle, which had a negligible effect. Furthermore, with increasing impact speed and concentration, all measured responses increased in both sample groups. The surface roughness values and mass loss increased by lower margins for the boronized samples (58.40% and 188.49%, respectively) compared to those of the raw samples (61.40% and 254.38%, respectively). This study demonstrates the potential of boriding as a surface treatment technique for enhancing the erosive wear performance of martensitic stainless steels, which require improved durability and longevity of materials subjected to erosive environments.

The SG‐Climbot: An Adaptable, Efficient, Inspection and Repair Robot for Steam Generator Heat Transfer Tube Sheet

ABSTRACTThe steam generator plays a crucial role as a safety component and protective barrier in nuclear power plants. Regular inspection and repair of heat transfer tubes, which operate in high‐temperature, high‐pressure, corrosive, and abrasive environments for extended periods, are essential. Inspection and repair robots move inside the steam generator to conduct comprehensive inspections and evaluations of the heat transfer tubes. However, existing robots have relatively simple execution devices and fixed movement methods, resulting in poor adaptability to different specifications of tube sheets and limited flexibility in handling maintenance tasks. In response to these limitations, the SG‐Climbot, a quadruped crawling tube sheet inspection and repair robot, has been proposed. This robot is designed to adapt to full‐specification tube sheets and operate efficiently by conducting inspections while moving. By comparing different motion modes, a robot configuration with a quadruped parallel structure was suggested. Kinematic and static analyses were conducted, resulting in the development of both forward and inverse kinematic models, along with the identification of conditions leading to tipping. Using parametric modeling and optimization design, optimized design parameters were obtained. Finite element simulation analysis was performed on the overall structure and main components, leading to an optimized structural model. Finally, based on the design model and computational analysis, a prototype was developed and tested. The experimental results indicate that the robot has achieved the expected functionality and performance targets. Its efficient maintenance operation mode of conducting inspections while moving provides a basis for the autonomous and intelligent development of steam generators.

Enhancing Wear Resistance of Marine Steel with Fe Based Amorphous Coating Via HVOF Spraying

Mechanical friction in marine environments poses significant challenges, leading to resource depletion and energy consumption. Tribocorrosion, combining electrochemical corrosion and friction wear, jeopardizes metal components, necessitating robust protective measures. Despite minimal wear of marine equipment, even slight mass reductions can trigger catastrophic failures, resulting in substantial maintenance expenses. Steel structures in marine settings are vulnerable to corrosion from aggressive external and internal factors. ASTM AH36 steel, widely used in marine construction, faces wear challenges despite corrosion resistance, prompting the need for surface treatments and coatings to enhance longevity. Previous research emphasizes thermal spray methods, particularly HVOF-applied coatings, as eco-friendly solutions for improving wear resistance on marine steels. Fe-based coatings, characterized by improved hardness and corrosion resistance, offer promising solutions in abrasive marine environments, igniting fervent research efforts. This study conclusively demonstrates that AH36 steel samples coated with Fe-based amorphous layers exhibit substantially reduced wear rates.

Friction and Wear Characteristics of Electrodeposited Ni‐Based Metallic Coatings on Cu‐Substrate under High‐Temperature Conditions

The Ni self‐lubricating coatings on copper substrates are deposited by electrodeposition using an aqueous electrolyte at room temperature. These coatings have the potential to improve the service life of Cu as a structural component in high‐temperature abrasion environments. A combination of low wear rate and coefficient of friction (CoF) is required in the coatings. Herein, friction and wear characteristics of the deposited Ni coatings are done by a ball‐on‐disc tribometer operated in the temperature range of 25–500 °C. The morphology and wear mechanism of tribo/transfer films are investigated using X‐ray diffraction, X‐ray photoelectron spectroscopy, and scanning electron microscopy. The CoF of Ni coating is substantially lower (CoF 0.37) at 500 °C than the Cu‐substrate, which is 0.79 at 25 °C. The Ni‐coating also reveals a low wear rate due to the formation of in situ oxides of Ni and Cu on sliding surfaces at high temperatures.

Mathematical Model of Vibration-Centrifugal Processing of Parts Using Loose Abrasive

The article presents some new theoretical and experimental solution of a scientific and applied problem of technological support for vibratory centrifugal processing of complex-profiled parts in a bulk abrasive environment. This solution aims to increase productivity while ensuring the desired quality of the processed surfaces. The authors have developed a mathematical model that describes the action of abrasive particles on the surface of the parts, taking into account the parameters of the granular abrasive medium based on Voigt’s law. This allows the description of dynamic processes in the processing environment for a wide range of material types. The natural frequencies of oscillations of the processed medium layer have been determined, which depend on the amplitude of its vibrations for different densities of soft and hard materials of the processed medium and the medium with linear-elastic properties. The methodology includes the use of test equipment to conduct experimental research on the process, which involves determining changes in specific metal removal rates and surface roughness using the frequency converter Altivar 71 with the PowerSuite v.2.5.0 software.

Kebertahanan Bangunan dengan Adaptif terhadap Lingkungan

Title: The Resilience of Buildings with Adaptability to the Environment (Case Study: Tomb of Syekh Mudzakir in Bedono, Sayung, Demak) Coastal areas have the potential to be affected by abrasion and tidal floods. Syekh Mudzakir's grave is in Tambaksari Subvillage, Bedono Village, Sayung Subdistrict, Demak District, and in the coastal area of the North Coast (Pantura) of Java Island. However, the existence of the tomb and its buildings to this day still survives amidst the marine environment that surrounds it. This tomb has become a religious tourism destination in Demak Regency, with the number of tourists increasing. This research aims to determine and explore the resilience of tomb buildings that are adaptive to abrasion and tidal flood environments. This research is field research. Research data uses primary data and secondary data through the results of observations, interviews, and documentation. The research analysis uses qualitative descriptive analysis. This research shows that Syekh Mudzakir's tomb does not float in the middle of the sea. However, the tomb survives adaptively to the environment by adapting the area, building development, building structural systems, and expanding the site to be robust against abrasion and tidal floods. This research concludes that the family and community survive the grave by adapting to the environment and mitigating disasters that befall the grave area.

Functionalized borosilicate-silica-epoxy nanocomposite superhydrophobic coating for corrosion inhibition under harsh environment

Current work proposes a facile scheme for fabrication of robust superhydrophobic borosilicate-silica-epoxy nanocomposite coatings on steel substrate with hierarchical structures, capable of inhibiting corrosion under harsh environment. The scheme amalgamates the advantageous properties of three ingredients: acid resistant property of borosilicate glass, superhydrophobic features of functionalized silica nanoparticles and durability of epoxy resin. The various steps of synthesis include 1. ball milling of borosilicate glass to micron and submicron size (~500 nm to 1.5 μm) 2. grafting of silica nanoparticles (~20 nm, through stober method) on the borosilicate particles to form rough hierarchical structure and 3. preparation of stable dispersion of the nanoparticles in epoxy-based resin followed by coating through immersion technique. Efficacy of the scheme was established through morphological, durability and electrochemical impedance studies. The surface morphology revealed hierarchical structures of functionalized silica nanoparticles (size range 20–100 nm) grafted on micro-sized borosilicate particles, which sustained water droplets with contact angle as high as 164.5° ± 2°. Sandpaper abrasion test proved excellent durability retaining hydrophobicity up to 250 abrasion cycles. The prepared surface maintained notable interface stability under aggressive environment: 3 and 10 days under pH 1 and 13 respectively. The electrochemical study in 3.5 wt% NaCl aqueous solution showed significant decrease in corrosion current density of coated surface (0.3585 μA/cm2) compared to uncoated surface (43.918 μA/cm2) suggesting excellent corrosion resistance. The results highlight scope of using this robust coating for abrasive and harsh environment.

Wear-resistant nickel-matrix composite coatings incorporating hard chromium carbide particles

This work evaluates the influence of plating variables on the morphology, composition homogeneity, and abrasive wear resistance of metal matrix composite coatings. A set of Ni/Cr3C2 coatings were brush plated onto steel coupons modifying two key variables: particle size and brush material. Compositional maps of unprecedented detail have been produced and analysed statistically to enhance understanding of composition distribution. The use of Abbott-Firestone curves to analyse surface morphology enabled the evaluation of valley and peak features. The coating differences highlighted by previous analyses have been compared with their behaviour in abrasive environments, simulated using Taber testing. Moreover, coupling Taber testing with partial compositional maps at different wear stages enabled monitoring of coating wear evolution. This methodology has revealed the importance of particle sedimentation during plating, which increased particle incorporation in the composite coating but also increased composition heterogeneity. The smaller 1.7 μm carbides and abrasive brushes produced coatings with more homogeneous morphologies, higher particle content, and increased resistance against abrasive wear, with a 60% reduction in material loss in comparison to the standard nickel coatings.

Eco-friendly porous composite of octaphenyl polyhedral oligomeric silsesquioxane and HKUST-1 with hydrophobic-oleophilic properties towards sorption of oils and organic solvents.

The degradation of water bodies caused by organic pollutants from industrial wastewater discharge has made it necessary to develop new functional materials like hydrophobic-oleophilic materials that can efficiently remediate water. It is factual that many of the synthetic methods for creating hydrophobic-oleophilic materials involve the use of toxic or harmful reactants, such as fluorine or sulfur compounds. However, these methods often have significant drawbacks, including being hazardous to the environment, expensive, and complex to utilize. Therefore, there is an urgent need to develop a hydrophobic/oleophilic material that is non-toxic and eco-friendly in order to overcome the existing drawbacks. In this regard, we have proposed a modest and eco-friendly approach for constructing a hydrophobic-oleophilic Ph-POSS@HKUST-1 composite material by solution-assisted self-assembly for the conversion of hydrophilic HKUST-1 into hydrophobic HKUST-1 for separation applications. The incorporation of fluorine-free, low surface energy and hydrophobic POSS into HKUST-1 increased the hydrophobicity and oleophilicity of the system. The synthesized Ph-POSS@HKUST-1 composite material has been thoroughly characterized through FT-IR, PXRD, HR-SEM, BET, and thermogravimetric analysis. It has been observed that the material exhibits a contact angle of 137 ± 4° and shows high selectivity and absorption capacity towards organic solvents and oils from water mixtures. Concurrently, the Ph-POSS@HKUST-1@PDA@sponge has been effectively utilized for the separation of solvents and oils and it has shown more than 95% separation efficiency for up to 15 cycles. It is interesting to note that Ph-POSS@HKUST-1 and the Ph-POSS@HKUST-1@PDA@sponge have outstanding stability in abrasive chemical environments which is due to the presence of a mechanically and chemically stable inorganic-organic hybrid POSS nanocage. In addition, ab initio and DFT calculations elicit that the Ph-POSS@HKUST-1 composite is stabilized through π⋯π stacking instead of the C-H⋯π mode of interaction at the HKUST-1⋯Ph-POSS interface. Further electron density features confirm the interfacial interaction at the interface. Our latest research has led us to propose an eco-friendly and non-toxic hybrid composite material for efficiently tackling the issue of organic solvent and oil pollution in water mixtures.

Assessment of the tribological performance of glass fibre reinforced polyamide 6 under harsh abrasive environments

High-performance thermoplastics exhibit significant potential to substitute metals in various applications, primarily due to their remarkable tribological, thermal and mechanical characteristics. Nevertheless, their characteristics require further refinement. This research aims to assess and compare the influence of distinct material types on the tribological characteristics of Polyamide 6 composites, as well as their reliance on the PV factor, which is the result of the velocity and pressure product.In the current research, the friction and wear performances of polyamide 6 (PA6) reinforced with glass fibres were examined in adverse PV factors till materials failed. Twin screw extrusion and subsequent injection moulding procedures were utilised to process the materials. The tribo-performance of the materials was assessed in ambient conditions using a pin-on-disc abrasive configuration. The morphological analysis of the abraded surfaces was conducted through field emission scanning electron microscopy (FESEM), and the plausible wear mechanisms contributing to wear are explained. Furthermore, the materials were thoroughly characterised for their tribological, mechanical and physical behaviours.The wear behaviour depended mainly on operating parameters and composition. PA6 proved to be beneficial till moderate PV conditions but not for harsh operating environments as compared to PA6 reinforced with 25% by volume of glass fibres (PA625GF). PA625GF showed PVlimit value of 1.04 MPa m/s which was decisively superior to PA6 (0.78 MPa m/s). Additionally, under a load of 50 N, PA625GF could sustain a higher speed of 800 rpm as compared to PA6 (600 rpm). The results showed that under all testing conditions glass fibres can minimise the coefficient of friction. Under low PV settings, the specific wear rate of PA625GF was remarkably reduced owing to the presence of glass fibres, reflecting superior anti-wear properties. Notably, the wear resistance of PA6 was considerably improved by glass fibres, particularly under high PV conditions, resulting in a PVlimit of 1.04 MPa m/s. The enhancement in PVlimit was attributed to the protective function of the fibres on the matrix and their superior mechanical properties. PA625GF proved to be tribo-potential materials in abrasive wear mode under extreme conditions in terms of low specific wear rate (8.484 ×10−3 mm3/N.m) and PVsafe value (0.78 MPa*m/s). This study is expected to pave the way for the development of novel self-lubrication composite materials for harsh service environments.

Deterioration mechanism of coral reef sand concrete under scouring and abrasion environment and its performance modulation

In complex marine environment, coral reef sand concrete structures such as breakwaters are subjected to abrasion by sand-containing currents, which seriously shortens the service life and cycle of structures. Therefore, this paper investigates the health status of on-site breakwaters, moreover, reveals the damage mechanism of coral reef sand concrete (CRSC) under scour and abrasion environments in combination with indoor macroscopic and microscopic experiments. In addition, the effects of fly ash (FA) and silica fume (SF) on the mechanics and durability, hydration and hydration products of CRSC are investigated so that corresponding measures can be proposed to improve the service performance of breakwaters. The results demonstrate the indentation hardness of coral aggregate is greater than that of ITZ and cement stone matrix. Therefore, the ITZ and cement stone matrix with lower hardness are scoured and abraded by water flow containing coral reef blocks with high hardness, resulting in abrasion failure of CRSC. FA and SF prolong the induction period of cement, and reduce the hydration rate and accumulated heat of the accelerated period and second peak. The hydration reaction between the supplementary cementitious material and Ca(OH)2 occurred within 20–40 h, resulting in the third exothermic peak of the system. The hydration process of the admixture-cement system goes through three stages: crystallization nucleation and crystal growth (NG), phase boundary reaction (I) and diffusion (D). FA mainly plays a physical filling role in the early stage, and it reduces the early C-S-H polymerization degree and the total volume of C-S-H phase, but slightly increases C-S-H polymerization degree in later stage. However, SF is involved in hydration reaction in the early stage, and increases the C-S-H polymerization degree and total volume of C-S-H phase.

Experimental investigation of three-body wear for rubber seals in abrasive slurry environment

Three-body wear is a complex phenomenon occurring when abrasive particles present between two material surfaces. By developing a new experimental setup, we systematically study wear at the contact between stainless steel and three different rubbers (TPU, NBR and LSR) in a slurry environment, i.e. water containing sand particles. Results showed that wear on both metal and rubber pads increases exponentially with the sliding speed, while a weak correlation was observed with the applied normal load for the given range of load. Wear analysis showed that the stainless steel experienced the most wear when in contact with NBR and the least when in contact with LSR. The TPU rubber pads experienced the most wear, whereas the LSR pads barely exhibit any wear when in contact with the stainless steel. Furthermore, frictional measurements indicated an inverse relationship between the system coefficient of friction and the amount of wear observed on the rubber elements. These observations are discussed in terms of the probability of the sand particles being clung to the rubber pads, after which they abrade the steel surface. This probability is justified as a function of the rubber material properties and the system friction coefficient. The findings in this study suggest new directions for minimizing three-body wear at the contact between metals and rubbers.

ОБРАБОТКА РЕЗУЛЬТАТОВ ЭКСПЕРИМЕНТАЛЬНЫХ ИССЛЕДОВАНИЙ ИСПОЛЬЗОВАНИЯ ТЕХНОЛОГИЙ КОМПЛЕКСНОГО МИКРОПЛАЗМЕННОГО УПРОЧНЕНИЯ РАБОЧИХ ОРГАНОВ И ДЕТАЛЕЙ СЕЛЬСКОХОЗЯЙСТВЕННЫХ МАШИН

Today, the problem of maintaining the efficiency of complex modern domestic and foreign agricultural machines is quite acute. The working units of agricultural tillage machines operate in an aggressive abrasive environment, which leads to their intensive wear and, as a result, to the loss of geometric shape. This, in turn, leads to a violation of agrotechnical requirements, which significantly affects the yield of cultivated crops. Serial working units of soil-cultivating machines are made of alloy steels of the ST65G type with a working hardness of HRC 55 ... 60. The purpose of the research is to increase the wear resistance of the working bodies of tillage agricultural machines by using the technology of complex microplasma hardening, with the development of a methodology for determining rational modes of processing working surfaces. To evaluate the effectiveness of complex hardening of laboratory samples, studies of the elemental composition of the hardened layer were carried out. Plates made of ST65G steel were used as laboratory samples. Hardening was carried out using various combinations of cermet powders and microplasma hardening modes. Determination of wear resistance was carried out on a friction machine 77 MT-1. The best results were noted after vibro-arc hardening followed by electrospark alloying and the use of a cermet powder consisting of 80% PG-10N-01 matrix powder and 20% B4C boron carbide. Based on the indicators of hardening regimes, Lagrange interpolation polynomials were constructed, which describe the dependence of the amount of sample wear on the current and voltage, an algorithm was developed for determining rational hardening regimes to achieve maximum wear resistance of the studied samples. The microhardness of the surface of products during electrospark hardening increased up to 2 times, and with vibroarc in combination with electrospark alloying and the use of special pastes with cermet powders - more than 3 times. The depth of the hardened surface layer with complex hardening is about 0.3 mm.

Износостойкость и совместимость исследуемых материалов для шарнирного узла черпаковой цепи

The current unfavorable environmental and hydro-technical situation in some regions of the country has cre-ated a number of serious problems. The government of the Russian Federation has created projects and programs where dredging is an integral part. There are carried out dredging works, among other things, by multi-bucket dredgers, where a scoop chain is the main working body. The performance and reliability of the chain depends on the quality of materials that experience high dynamic loads, and the consequences of the abrasive environment, which leads to accelerated wear of the swivel. There are given the results of the study of wear characteristics, the range of compatibility of steels and alloys of the hinged connection of the dredger bucket chain and the technology for the restoration of these elements, with an increase in the resource of the chain connection unit. Experimental studies simulating the wear of the assembly on small-sized samples determined the wear re-sistance of the materials of the pair. The method of comparative analysis with reference pairs was used. The experimental material consisted of 13 pairs, including 2 pairs of standards made of steel 110Mn13, 38CrNi3M (sleeve-finger) and steel 110Mn13 (sleeve and finger), where the remaining pairs were made of materials: steels C35K, C45K, 110Mn13, 38CrNi3Mo, wear-resistant surfacing with E – 190Cr5Si7 – LEZ – T – 590 – NG electrodes, surfacing with wire SV08A, electrodes E50A – UONI 13/55 (E513B20H), E46 - ANO-4 (E433R24) after a complex of heat treatments, chemical-thermal treatments, surface plastic deformation, where the samples were subjected to a load of 6615 N (675 kgf) in water-abrasive medium, were tested on the friction machine. Fundamental dependences are revealed and graphs of the influence of the hardness of the samples and the carbon content of the friction surface on the wear-resistant characteristics of various structural classes are plotted. Promising pairs for full-scale tests were determined: 1. steel 110Mn13 (sleeve) - surfacing SV08A with chemical-thermal treatment (finger); 2. steel 38CrNi3Mo (sleeve) - steel C35K with chemical-thermal treatment (finger); 3. steel C35K with chemical-thermal treatment (sleeve) - cladding SV08A with chemical-thermal treatment (finger).

Fabrication of a Charge-Conversion Polymer—Liposome for Enhancing Endosomal Escape of Drug Delivery System for α–Mangostin

α–Mangostin, which is a natural xanthone compound, inhibits the metastasis and survival of various cancer cell types. However, its therapeutic effectiveness is limited by low water solubility and very poor absorption. There are several studies that developed the drug delivery system for α–mangostin, but they are still a remaining challenge. Drug delivery techniques are severely hampered by the breakdown of nanoparticles inside endosomes. The abrasive chemical environment in these compartments causes both the nanoparticles and the encapsulated α–mangostin to degrade throughout the course of the voyage. Intracellular defenses against external materials refer to this collective mechanism. A pH-responsive liposome named PAsp(DET-Cit)–Toc, made of lipids and a charge-conversion polymer (CCP), has been created for the targeted transport of α–mangostin in order to avoid this deteriorative outcome. The average hydrodynamic size of CCP–liposome particles is 98.59 ± 5.1 nm with a PDI of 0.098 ± 0.02 and a negative zeta potential of 22.31 ± 2.4 mV. TEM showed the shape of the spherical CCP–liposomes. α–Mangostin is successfully captured inside CCP–liposome and the loading yield reached the highest encapsulation efficiency of 83% with 150 μg/mL of α–mangostin. In the acidic condition of pH 5.0, an initial burst of α–mangostin reached 50% after 6 h in buffer solution. CCP–liposomes could escape from endosomes even after 3 h, and almost 80% of CCP–liposomes escaped after 24 h. The cell ability of α–mangostin-loaded-CCP–liposome incubated in buffer solutions of 5.0 decreased significantly and was close to free α–mangostin. Our data proved that α–mangostin-loaded CCP–liposome delivered more effectively α–mangostin into cells and prevented the degradation of α–mangostin inside cells, especially endosomal degradation.

Fusion of Ni Plating on CP-Titanium by Electron Beam Single-Track Scanning: Toward a New Approach for Fabricating TiNi Self-Healing Shape Memory Coating.

The limited wear resistance of commercially pure titanium (CP-Ti) hinders its use in abrasive and erosive environments, despite its good strength-weight ratio and corrosion resistance. This paper reports the first study proposing a novel method for wear-resistant TiNi coating through Ni plating and electron beam (EB) irradiation in an in situ synthetic approach. Single-track melting experiments were conducted using the EB to investigate the feasibility of forming a TiNi phase by fusing the Ni plate with the CP-Ti substrate. Varying beam powers were employed at a fixed scanning speed to determine the optimal conditions for TiNi phase formation. The concentration of the melt region was found to be approximate as estimated from the ratio of the Ni-plate thickness to the depth of the melt region, and the region with Ni-48.7 at.% Ti was successfully formed by EB irradiation. The study suggests that the mixing of Ti atoms and Ni atoms was facilitated by fluid flow induced by Marangoni and thermal convections. It is proposed that a more uniform TiNi layer can be achieved through multi-track melting under appropriate conditions. This research demonstrates the feasibility of utilizing EB additive manufacturing as a coating method and the potential for developing TiNi coatings with shape memory effects and pseudoelasticity.

Управление эксплуатационными свойствами порошковых материалов для повышения коррозионной стойкости и износостойкости деталей

Introduction. One of the vibration methods for processing loose finely dispersed mineral raw materials is the sepIntroduction. The quality of powder materials made of rare metals is ensured by chemical-thermal treatment, including diffusion chromosilidation. Chemical and thermal treatment of products intensifies the process of diffusion saturation, reduces the processing time and allows the use of products in aggressive and abrasive environments. Methods and materials of research. Systematization, generalization and analysis of theoretical, laboratory and experimental studies, the basis of which is the modeling of processes. Research results. It was found that when using low-alloyed powder, higher strength and viscosity indices of chromosilicated materials were obtained. It is determined that the mechanical properties of powders processed from molten salts are higher than those of materials from powder filling. It is shown that the treatment increases the corrosion resistance of iron-based powders with an established corrosion rate less than the initial one. Discussion of research results. The rapid formation of an oxide film that protects the metal from corrosion is facilitated by quenching and normalization. Porous chromosilicated layers are destroyed and impair the ability of the material to resist corrosion destruction. The operational properties of chromosilicated powders obtained by hot stamping methods increase when using rational parameters of the technological process in an optimal mode. Conclusion. The article contains new proposals for managing the properties of materials to increase corrosion resistance and wear resistance of children. Conclusions on the article. New developments can be recommended for implementation in the production of rare metals and products made from them. Suggestions. The results of the research can be used both in the modernization of production and in the training of specialists in this field.

Evaluation of Hot Corrosion Behavior of WC-Co-Cr Coatings Coated by the HVOF Method

Thermal spray coating techniques have wide-ranging applications in various fields, including marine, automotive, biomedical, and aerospace industries. These methods are popularly used because materials coated with thermal spray coatings exhibit excellent resistance to oxidation, erosion, corrosion, and abrasive environments, particularly at high temperatures. The present study utilized the high-speed oxy-fuel (HVOF) technique, a state-of-the-art thermal spray coating method, to apply a hard cermet ceramic coating material consisting of WC-Co-Cr onto a 316L stainless steel substrate. Isothermal hot corrosion tests were also conducted at 750°C in the presence of 45% Na2SO4 and 55% V2O5 hot corrosion salts for 1, 3, and 5 hours. Advanced characterization techniques such as X-Ray Diffractometry (XRD), Energy Dispersive Spectrum (EDS), scanning electron microscopy (SEM), and elemental mapping analysis devices were used to characterize the samples coated with the HVOF technique before and after hot corrosion tests. The findings indicate that WC-Co-Cr hard coatings, which are known for their high resistance to abrasion, sustain severe damage at high temperatures. The coating was damaged after 5 hours in the hot corrosion tests performed in the presence of V2O5 and Na2SO4 molten salt at 750°C.