High Abrasion Research Articles

Multifunctional superhydrophobic coatings with self-cleaning and anti-fouling properties for corrosion protection of metals

Superhydrophobic coatings have self-cleaning, antifouling, and anti-corrosion properties due to their unique surface properties, but their disadvantages such as poor durability, poor mechanical properties, and complicated preparation methods severely limit their practical applications. Here, super hydrophobic coatings with high abrasion resistance and long-lasting corrosion resistance were prepared by a simple spraying method using stearic acid-modified titanium dioxide nanoparticles (TiO2), polyphenylene sulfide (PPS) as the base material, and doped polyvinylidene difluoride (PVDF). The SA-TiO2 can provide low surface energy and rough structure, and the PPS itself has high mechanical strength and corrosion resistance properties. The PVDF doping can generate cross-linking inside the coating to improve the densification and mechanical strength of the coating, while the formation of irregular micrometer-sized protrusions can play a role in protecting the nano-surface. he synergistic effect of the various components results in an excellent mechanical stability of the coating, which remains superhydrophobic after a 400 cm sanding test. In addition, the coating has excellent corrosion resistance, and the electrochemical impedance spectroscopy (EIS) results show that the impedance modulus of the coating is as high as 21.99 kΩ· cm2. The coating has a hierarchical micro-nano structure, and shows excellent mechanical and corrosion resistance, which is of great potential for practical applications.

Superdurable Full-Life Superhydrophobic Composite Block.

Superhydrophobic materials are attractive for industrial development but plagued by poor mechanical stability. Herein, a superdurable full-life superhydrophobic composite block is designed and fabricated by embedding near-zero contractive superhydrophobic silica aerogel into a rigid iron-nickel foam structured similarly to a regular dodecahedron. The synergistic protection afforded by these materials ensures superrobust mechanical stability for the composite block, which features a high compressive strength of up to ≈7.4MPa, and ultralow Taber abrasion of down to ≈0.567mm after withstanding 50000 cycles, and highly efficient water harvesting capability of up to ≈3114.3mg min-1 cm-2 at a supercooling degree of 40 K. This robust material system provides a novel strategy to design superhydrophobic materials capable of withstanding extreme conditions, including high temperature, humidity, pressure, and abrasion.

Stain removal, abrasion and anticaries properties of a novel low abrasion dentifrice containing micro-fibrillated cellulose: in vitro assessments

ObjectivesThis laboratory study assessed the performance of a novel fluoride dentifrice containing micro-fibrillated cellulose (MFC) and entrapped silica. MethodsRemoval of extrinsic stains was assessed using the pellicle cleaning ratio (PCR) method, and radioactive dentin abrasivity (RDA) was measured, to calculate a cleaning efficiency index (CEI). Fluoride efficacy was evaluated using widely used remineralization and fluoride uptake methods. The test product (Protegera™) was compared to common dentifrices (Crest - Cavity Protection™ and ProHealth™, Sensodyne Pronamel™, Arm & Hammer™ Advanced Whitening, Crest ProHealth™, and Colgate Optic White™). ResultsThe PCR for the MFC dentifrice (141) was comparable to three known marketed stain-removing dentifrices (Arm & Hammer™ Advanced Whitening, Crest ProHealth™, and Colgate Optic White™) but it had a significantly lower RDA (88 ± 6) than 5 other products. This gave it the highest CEI of the tested products (2.0). In a 10-day pH cycling study, the fluoride efficacy of the MFC product was comparable to Sensodyne Pronamel and Crest Cavity Protection. The MFC dentifrice was superior for promoting fluoride uptake into incipient enamel lesions compared to the USP reference dentifrice. ConclusionThe MFC dentifrice has low abrasion, but despite this, it is highly effective in removing stained pellicle. It also is an efficacious fluoride source when compared to relevant commercially available fluoride dentifrices with high dentin abrasivity. Clinical significanceThe addition of micro-fibrillated cellulose to a fluoride dentifrice gives a low abrasive product that can effectively remove external stains, and serve as an effective fluoride source. This combination of benefits seems well suited to enamel protection and caries prevention.

A Comparative Study about Production of Va nadium Carbide via Self Propagating High Temperature Synthesis and Reduction

Vanadium carbide is important for industrial applications because of its high hardness, high temperature resistance, high chemical, and thermal stability. It is generally obtained from the reaction between V and C powders at a high temperature ranging from 1100 to 1500°C. Investigations on these high strength, high abrasion resistant, hard materials have been intensified in recent years and consequently, significant improvements have been achieved. In this study, VC alloys are produced with low cost processes, by reducing the oxides of their components by SHS methods and ball mill-assisted carbothermal reduction. In the experimental stage, V2O5 was used as oxidized Vanadium source, Cblack as carbon source, magnesium and Cblack as reductant. In the study, VC powders were synthesized by two different methods and optimum production conditions were determined. Furthermore, the effect of different stoichiometric charge components and the effect of experiment durations were realized by X-ray diffraction, HSC Chemistry, and SEM analyses for different reductants.

Effect of Cooling Rate on Microstructure and Mechanical Properties According to Heat Treatment Temperature of Inconel 625

Inconel 625 is typically used in extreme environments due to excellent mechanical properties such as high strength, corrosion resistance, abrasion resistance and low-temperature toughness. When manufacturing a hot forged flange with a thick and complex shape, the cooling rate varies depending on the location due to the difference in thermal gradient during the cooling process after hot forging. In this study, to evaluate the microstructure and mechanical properties of Inconel 625 according to the cooling rate, we performed heat treatment at 950°C, 1050°C, and 1150°C for 4 hours followed by water cooling. Additionally, temperature data for each location on the flange were obtained using finite element method (FEM) simulation for each heat treatment temperature, revealing a discrepancy in the cooling rate between the surface and the center. Therefore, the correlation between microstructure and mechanical properties according to cooling rate was investigated.

A wood wax oil-based nanocomposite coating with excellent durability, ultraviolet and water resistance for wood finishing

The development of a multifunctional wood wax oil-based coating holds significant importance in meeting demands for wood protection and enhanced longevity of wood materials. Nevertheless, a simple method of developing such an integrated coating that possesses excellent durability, ultraviolet (UV) resistance, water resistance, and environmental friendliness remains a significant obstacle. In this paper, stearoyl chloride-grafted cellulose nanocrystals (SCNCs) with excellent compatibility with wood wax oil (WWO) coatings were prepared by combining cellulose nanocrystals (CNCs) with stearoyl chloride through a one-step non-homogeneous esterification reaction. Nanocomposite coatings were prepared by a simple one-step ultrasonic miscibility method using SCNCs as modified functionalized fillers. The prepared SCNC-WWO wood coatings had high hardness (grade H), strong adhesion (class 0, with no peeling), high abrasion resistance, good UV resistance, high hydrophobicity (water contact angle of 116°), and good water resistance (maintainable for 1 day). In addition, SCNCs with gas barrier properties can effectively inhibit the release of pollutants within the coatings, making this composite coatings environmentally friendly. Therefore, SCNC-WWO can be used as a high-performance coating for substantial protection of wood in harsh environments, and the strategy for developing it provides insight into the preparation of multifunctional wood paint.

Preparation and properties of high abrasion resistant superhydrophobic coating on the PCB

Abrasion resistance has become the bottleneck restricting the application of superhydrophobic surface. It is extremely necessary to design superhydrophobic surface with high abrasion resistance in practical application environment. However, the coexistence of superhydrophobic property and abrasion resistance is a difficult challenge to balance. In this study, a superhydrophobic coating with high abrasion resistance was obtained in combination with three gradients of roughness/wettability, physical adhesion and chemical coupling on the printed circuit board (PCB) surface. The realization of high abrasion resistance of the coating mainly depended on controlling the curing time of the adhesive layer and the way of air injection, so that the micro-nano structure could achieve the effect of semi-embedded. The PCB surface still maintained superhydrophobicity with the water contact angle higher than 150° after a series of tests such as 800 cycles of tape peeling, 400 cycles of knife scraping, 2600 cm of sandpaper abrasion, 425 g of falling sand impacting, and 60 min of water impacting, which fully proved the high abrasion resistance of the coating and the strong adhesion between the coating and the substrate. The preparation process is high efficiency and suitable for large area application, which will provide an extremely valuable idea for improving the waterproof of PCB and promote the true applications of superhydrophobic coating in many fields.

Effect of boron addition on the microstructure and wear resistance of laser beam directed energy deposited high chromium white irons

There is a demand for alloys produced by laser beam directed laser deposition (DED-LB) with better wear resistance than the traditionally manufactured alloys. In DED-LB of high chromium white iron (HCWI), the refined carbides at the micron scale can lead to inferior wear performance than the cast alloy of the same composition. In this study, various concentrations of FeB powder were mixed with HCWI powder and produced by DED-LB. The microstructural evolution and its relationship with the wear resistance in high stress abrasion wear test were studied. The B addition is a C equivalent element in HCWI, which can change the composition from hypoeutectic to hypereutectic. In the hypereutectic alloys, B promotes hard phases in the form of M7(C,B)3 and M3(C,B) (M mainly represents Cr and Fe). With the B additions, the volume loss in high stress wear testing is reduced due to the increase in the fraction of the hard phases and their coarsening. With the predominantly austenitic matrix, the alloy with 1.09 wt % B consisting of near 60 vol% hard phases showed a superior wear performance than the heat-treated cast alloy. This was attributed to the microstructure in the contact. The high fraction of refined hard phases and the relatively ductile austenitic matrix (compared with the martensitic matrix) work synergistically, showing a worn surface of plastic deformation without brittle spalling and pitting.

Fabrication of high thermal conductivity and wear resistance graphite/copper composites by microwave hot press sintering

Graphite/copper composites have great potential for tribological applications because of their high thermal and abrasion resistance. In this study, we successfully manufactured graphite/copper composites that demonstrated superior thermal conductivity and wear resistance by employing microwave hot press sintering (MHPS). The results demonstrated an enhancement in the density and hardness of the composites as the graphite particle size increased, owing to the influence of MHPS. Meanwhile, the graphite/copper composite with a graphite particle size of 300 µm has excellent thermal conductivity and friction properties, with a thermal conductivity of up to 679.5 W/mK and a wear rate of only 3.019 10−6 cm3/(N·m). The work is expected to provide a new route for the developing highly thermally conductive and abrasion-resistant materials.

PFS 1.0: A development tool applied to vision-based tactile sensor process formulation and fabrication

Vision-based tactile sensors (VBTS) have gradually garnered attention for their high performance. However, there is a lack of detailed technology summaries and available tools for process formulation. To simplify the development flow, this paper proposes a process formulation system (PFS) and establishes a visualization interface based on QT. The developer inputs the design goal, and the system automatically corrects these goals and then matches the process schemes by dictionary search. Following the fabrication sequence, the system outputs a complete reference fabrication flow. Furthermore, the PFS provides more comprehensive process details than large models. In addition, the PFS universality is verified via representative VBTS cases. A multimodal visuo-tactile skin (VTS) is developed with the PFS. The fabrication process of elastomer and coating is optimized based on the reference process. The results show that the VTS prototype achieves micron-level spatial resolution, high sensitivity, and high abrasion resistance. Consequently, the PFS is expected to provide technology guidance and assistant development for beginners and developers in this area.

Preparation and Characterization of Activated Palm Kernel Shell/Carboxylated Nitrile Butadiene Rubber (APKS/XNBR) Vulcanizate

Malaysia is one of the most important palm oil producers and exporters in the whole wide world. There has been a rapid development of new palm oil plantations and palm oil mills in this country. The palm oil industry plays a vital role in the economic growth of Malaysia. However, as the palm oil industry grows bigger and wider, a huge amount of palm oil waste is produced which is an alarming issue considering it can cause pollution and have a negative effect on the environment. Raw Palm Kernel Shell (PKS) derived from palm oil waste can be converted into Activated Palm Kernel Shell (APKS) which has the potential to be a value-added biofiller in rubber vulcanizates. Thus, in this study, APKS is prepared through a carbonization process at a temperature of 900 °C and an activation process via steam treatment and used as filler in Carboxylated Nitrile Butadiene Rubber (XNBR). The aim of this study is to evaluate the influence of different loading ratios of APKS on theswelling index measurement, bound rubber content (BRC), abrasion resistance, compression set, and hardness of XNBR vulcanizates. APKS is incorporated in XNBR at different loading ratios, ranging from 0 to 50 phr and these APKS-filled XNBR vulcanizates are prepared with a two-roll mill. The overall physico-mechanical properties of APKS-filled XNBR vulcanizates showed increment in terms of BRC, compression set, and hardness as the loading ratio of APKS increased. XNBR vulcanizates with a higher loading ratio of APKS also showed a decrease in swelling index measurement and volume loss which would indicate high abrasion resistance. These results could be attributed to the porosity of APKS as shown in the morphological analysis which provided a high surface area of contact for crosslinking and mechanical interlocking. This proves APKS could potentially be a semi-reinforcing filler for rubber vulcanizates, especially for XNBR vulcanizates as XNBR vulcanizates were able to achieve high abrasion resistance and high hardness with the incorporation of APKS. With this, the conversion of PKS into APKS could help to reduce palm oil waste and provide an environmentally friendly, sustainable biofiller option to rubber researchers and manufacturers who are looking for an alternative to petroleum-based fillers. This would be very beneficial for both the palm oil industry and the rubber industry.

Wear resistance of self-sharpening blades of the tillage cultivator pointed tines

The paper studies the wear of the working surfaces of the cultivator’s pointed paw caused by multiple deformations by solid particles with high abrasiveness and mechanical properties of the soil. The main purpose of the study is to develop a methodology for determining the wear resistance of self-sharpening cutters of the cultivator’s pointed paws. Factors influencing the traction of working bodies and causing wear of working surfaces have been identified. The studies can be of interest to the specialists involved in tillage.

Synthesis of a water-based TEOS–PDMS sol–gel coating for hydrophobic cotton and polyester fabrics

TEOS–PDMS coating was synthesized without any organic solvent. While it exhibited good durability in high temperatures and abrasion tests, further refinement is necessary to mitigate the decline in hydrophobicity resulting from washing cycles.

Identification of mangrove damage and mangrove ecosystem management efforts in Ekasoghi Tourism, Saronggi District, Sumenep Regency

The Saronggi District area, Tanjung Village has experienced changes in the structure of mangroves which resulted in a decrease in the number of mangroves due to mangrove tourism, lack of awareness of the importance of mangroves, and damage due to human activities. The purpose of this study is to find the causes of mangrove damage and formulate policies in the management of mangrove ecosystems in the Ekagoghi tourist area. This research was conducted with visual observation (descriptive narrative) and SWOT analysis to consider management policy strategies. The types of mangroves found on the coast of Ekasoghi in Sumenep Regency consist of species Osbornia octodonta, Sonneratia alba, Avicennia marina, Rhizophora mucronata, Lumnitzera racemosa, and Rhizopora apiculata which have been damaged by natural factors and human actions. The causes of mangrove damage include high beach abrasion so that beach erosion occurs and causes a reduction in nutrients and seaweed cultivation which causes damage to mangrove trees due to the charts used. Policies that need to be carried out for the management of mangrove ecosystems on Ekasoghi Beach, namely by holding wanamina cultivation (silvofishery) and the implementation of an ecopreneurship system, can be considered to develop policies directed to explore profit potential and maintain the sustainability of the existence of preserving mangrove ecosystems. This policy certainly needs to be supported by strengthening community institutions and cooperation between government institutions.

Geosynthetic solutions for river and coastal protection works

Riverine floods and coastal erosion are some of the most frequent natural calamities in India that affect millions of people, cause loss of lives, and damage infrastructure and agriculture. Application of geosynthetic products provides a sustainable, eco-friendly, quick & economical solution among all the conventional river and coastal protection works. This paper focuses on geosynthetic solutions to the river and coastal erosion with the help of case studies. To safeguard against the frequent floods, the banks of the river Brahmaputra near Lakhimpur were strengthened while providing geosynthetic anti-erosion measures. A sandfilled geotextile mattress of 0.1m thickness was provided on the river bank slopes of the Brahmaputra River, Assam. Also, this paper reveals the successful application of specially engineered nonwoven geotextile bags with high abrasion resistance, to mitigate the effects of erosion of the banks of Churni River, West Bengal. This solution reinforces the embankment's edge and increases the factor of safety against repeated floods. The third case study discusses the coastal protection work at Kattupalli, Tamilnadu where a 620ms long shoreline was protected against progressive beach erosion. An embankment was formed using 6 numbers of 3.0m theoretical diameter and 20.0m long high-performance geotextile tubes in crosssection and a small geotextile tube was used for scour protection ahead of the structure. The embankment thus formed also provided ways for beach nourishment and land reclamation at the site.

Influence of NR/EPDM Ratios on the Performance of Pneumatic Fenders in Seawater

The performance of pneumatic fenders in seawater is crucial to ensure safety and serviceability. Hence, the objective of this study is to investigate the performance of compound formulations of two different types of carbon black N660 and N220 at various NR/EPDM (Natural Rubber/Ethylene Propylene Diene Monomer) ratios of 100/0; 90/10; 80/20, and 70/30 in artificial seawater at 95°C for 30 days. The mechanical properties of rubber compounds were measured and compared before and after aging in seawater. Comparing two types of carbon black, no significant difference in tensile, elongation, tear strength, and compression set at the same blend ratios after aging in seawater. Nevertheless, the abrasion resistance of N220 is lower than that of N660 before and after aging in seawater due to insufficient dispersion. Adding high crystalline EPDM in the blend results in lower mechanical properties change than pure NR after aging in seawater. In addition, the blend contains EPDM imparts high abrasion resistance in seawater. Using EPDM up to 30 phr in the blend with NR indicates the possibility of utilizing this high oxidation stability of rubber as a pneumatic fender.

The Influence of Curing System on the Macroscopic Performance and Microstructure of Anti-Abrasive UHPC

In a previous study, we utilized saturated prewet high titanium heavy slag sand to produce UHPC (ST-UHPC). ST-UHPC has high impact and abrasion resistance. For better ST-UHPC applications, we investigate the mechanism of ST-UHPC under different curing systems from the microstructure and macroscopic perspective in this paper. We prepared ST-UHPC under four maintenance conditions: 20 °C standard curing, 90 °C steam curing, 90 °C dry curing and 210 °C 2 MPa pressure steam curing. Then, we analyzed the hydration product composition, the degree of cement hydration, the C-A-S-H gel microstructure and the substitution of Al3+ for Si4+ in relation to these prepared ST-UHPCs. Compared with standard curing, dry curing at 90 °C accelerated the water evaporation and reduced the hydration degree of ST-UHPC cementite. However, pressure steam curing significantly improved the hydration degree of ST-UHPC cementing material, and increased the MCL and Al[4]/Si of C-A-S-H gel. In addition, pressure steam curing reduced the Ca/Si and promoted the conversion of C-A-S-H cementing to tobermorite. Compared with dry curing at 90 °C, pressure steam curing significantly improved the macroscopic properties of ST-UHPC. The macro-performance difference of ST-UHPC under standard curing and 90 °C steam curing is small. The reason is that steam curing caused the water to be rapidly released in the internal aggregate of ST-UHPC. This resulted in the increase of the interface between the internal aggregate of ST-UHPC and the ST-UHPC cementate. The harmful pores in the ST-UHPC matrix under steam curing were also increased. To sum up, compared with standard curing, dry curing at 90 °C weakened the mechanical properties and microstructure of ST-UHPC, but steam pressure curing increased them. The single steam curing had no significant effect on the mechanical properties and microstructure of the ST-UHPC. Therefore, non-steam and room-temperature moisturizing maintenance should be adopted for anti-abrasive UHPC.

Robust and applicable superhydrophobic coatings with multi-layer self-similar structure and self-healing properties

To prepare durable superhydrophobic coatings with low-cost is of great importance for its practical application. How to improve the mechanical endurance by a facile method is rarely mentioned in reports. Achieving thicker coating with multi-layer micro-nano structures is critical for obtaining the robust superhydrophobic coating due to the high abrasion resistance to mechanical damage. Herein, a superhydrophobic coating with a multi-layer self-similar structure was fabricated by a facile blending and spraying method. Epoxy resin, neutral silicone glue, polysiloxane and nano-SiO2 are the main composition of the ESPS coating which are important for the multi-layer micro-nano structure construction and adhesion stability between the coating and the substrate. The water contact angle (WCA) and sliding angle (SA) of the ESPS coating were 162.5 ± 0.5° and 4.6 ± 0.4°, respectively. Notably, the ESPS coating with four layers can be abraded with 1500-grid sandpaper under the load of 400 Pa for 24 m. In addition, the prepared samples were put in an outdoor environment for 180 days and exhibited excellent durability and stability. These outstanding properties could be attributed to the hierarchical self-similar structure of the composited coating and the good resistance and adhesion stability provided by polysiloxane. Additionally, the ESPS coating could restore its superhydrophobic characteristic by self-healing realized by the neutral silicone glue in the composition. The good stability and operability of the ESPS coating make it applicable to a wide range of applications.

Spark Plasma Sintering of Fine-Grained WC-Co Composites.

Cemented carbides WC-Co are one of the basic tool materials. They constitute over half of the currently used tools intended for machining. The main advantages of WC-Co cemented carbides are high hardness and abrasion resistance. The properties of WC-Co sinters depend mainly on the content of the binding phase, the sintering method and the grain size of the powder from which the sinters were made. The aim of this study was to produce fine-grained WC-Co composites using SPS (spark plasma sintering) technology, as well as examine the effect of the applied technology on the basic properties of WC-Co sinters: microstructure, hardness, phase composition, compaction degree and tribological properties. In the processes carried out, no additives affecting the reduction in grain growth were used. Sintering was conducted at a temperature of 1200 °C with a holding time of 10 min. The process occurred under a load of 100 MPa. Finally, the samples were cooled in a vacuum of 10-6 mbar. We measured the hardness using a Vickers hardness tester. We took hardness measurements along the diameter of the sintered samples. In order to ascertain the fracture toughness (KIC), we measured the radial crack length around the Vickers indentation and applied Shetty's formula. The tribological tests were carried out with a tribotester using the T-01 ball-on-disc method. The obtained data enabled the characterization of the wear process of the tested materials.

Durable Radiative Cooling Multilayer Silk Textile with Excellent Comprehensive Performance

AbstractPassive radiative cooling without energy consumption is increasingly being explored as an eco‐friendly alternative to electric cooling for mitigating heat stress caused by global warming. Incorporating radiative cooling into personal thermal management has garnered widespread interest. However, existing sub‐ambient radiative cooling textiles face challenges related to inferior solar reflectance, poor outdoor durability, or health concerns. Here, a durable multilayer silk textile (MST) is developed that achieves excellent comprehensive performance for the first time, including both ultrahigh solar reflectance (96.5%) and ultrahigh infrared emittance (97.1%), safety, air and moisture permeability, high mechanical strength, washability, abrasion resistance, surface hydrophobicity, and UV resistance. The MST achieves a remarkable sub‐ambient temperature drop of 5.1 °C under 892.4 W m−2 of ultra‐strong solar radiation and surpasses both commercial silk and cotton textiles at noon with temperature reductions of 6.0 and 8.3 °C, respectively. For proof of concept, a hat using the MST is fabricated, which shows improved cooling performance compared to commercial hats. Considering its outstanding cooling performance, durability, zero energy consumption, abundant raw materials, and scalable production ability, it is believed that the radiative cooling MST holds great promise for practical applications in daytime personal thermal management.