Mechanical Grinding Research Articles

A Novel Reclamation Method of Chemical–Mechanical Grinding for Inorganic Binder Waste Sand in Aluminum Alloy Casting Process

A Novel Reclamation Method of Chemical–Mechanical Grinding for Inorganic Binder Waste Sand in Aluminum Alloy Casting Process

Effect of surface pretreatment on the polypyrrole coating of acrylonitrile butadiene styrene. Part A: Synthesis and characterization

This paper investigates the synergistic effects of a two-step surface modification approach on acrylonitrile butadiene styrene (ABS) plastics. The first step involves a mechanical grinding pretreatment followed by chemical etching in sulfuric acid and hydrogen peroxide, which increases surface roughness and enhances the wettability of the ABS surface. The second step focuses on the chemical synthesis of polypyrrole (PPy) on the pretreated ABS, demonstrating improvements in PPy surface roughness and adhesion after grinding and chemical etching. Adhesion tests reveal a significant increase from 0 % (PPy on untreated ABS) to 66 % (PPy on the grounded ABS) and ultimately to 100 % (PPy on the grounded ABS after chemical etching). This research is dedicated to a comprehensive exploration of the fundamental mechanisms, substantiated by a rigorous analysis involving X-ray photoelectron spectroscopy (XPS) examination, scanning electron microscopy (SEM) and contact angle measurements. Furthermore, the electric conductivity of PPy coatings is enhanced through electrochemical doping of PPy using dodecyl sulfate anions (DS/PPy/ABS) and the incorporation of silver particles (Ag/PPy/ABS). Raman spectroscopy demonstrates the Surface-Enhanced Raman Scattering (SERS) effect of silver particles on PPy coatings, showcasing their interaction. X-ray diffraction (XRD) confirms the enhanced crystallinity of DS/PPy/ABS, aligning with increased conductivity after electrochemical doping with DS anions.

Structure and Properties of Bioactive Titanium Dioxide Surface Layers Produced on NiTi Shape Memory Alloy in Low-Temperature Plasma.

The NiTi alloy, known for its shape memory and superelasticity, is increasingly used in medicine. However, its high nickel content requires enhanced biocompatibility for long-term implants. Low-temperature plasma treatments under glow-discharge conditions can improve surface properties without compromising mechanical integrity. This study explores the surface modification of a NiTi alloy by oxidizing it in low-temperature plasma. We examine the impact of process temperatures and sample preparation (mechanical grinding and polishing) on the structure of the produced titanium oxide layers. Surface properties, including topography, morphology, chemical composition, and bioactivity, were analyzed using TEM, SEM, EDS, and an optical profilometer. Bioactivity was assessed through the deposition of calcium phosphate in simulated body fluid (SBF). The low-temperature plasma oxidization produced titanium dioxide layers (29-55 nm thick) with a predominantly nanocrystalline rutile structure. Layer thickness increased with extended processing time and higher temperatures (up to 390 °C), though the relationship was not linear. Higher temperatures led to thicker layers with more precipitates and inhomogeneities. The oxidized layers showed increased bioactivity after 14 and 30 days in SBF. Low-temperature plasma oxidation produces bioactive titanium oxide layers on NiTi alloys, with a structure and properties that can be tuned through process parameters. This method could enhance the biocompatibility of NiTi alloys for medical implants.

The influence of HKUST-1 and MOF-76 hand grinding/mechanical activation on stability, particle size, textural properties and carbon dioxide sorption

In this study, we explore the mechanical treatment of two metal–organic frameworks (MOFs), HKUST-1 and MOF-76, applying various milling methods to assess their impact on stability, porosity, and CO2 adsorption capacity. The effects of different mechanical grinding techniques, such as high-energy ball milling and hand grinding, on these MOFs were compared. The impact of milling time, milling speed and ball size during high-energy ball milling was assessed via the Design of Experiments methodology, namely using a 33 Taguchi orthogonal array. The results highlight a marked improvement in CO2 adsorption capacity for HKUST-1 through hand milling, increasing from an initial 25.70 wt.% (5.84 mmol g-1) to 41.37 wt.% (9.40 mmol g-1), marking a significant 38% increase. In contrast, high-energy ball milling seems to worsen this property, diminishing the CO2 adsorption abilities of the materials. Notably, MOF-76 shows resistance to hand grinding, closely resembling the original sample’s performance. Hand grinding also proved to be well reproducible. These findings clarify the complex effects of mechanical milling on MOF materials, emphasising the necessity of choosing the proper processing techniques to enhance their stability, texture, and performance in CO2 capture and storage applications.

Surface microstructuring of hot-rolled carbon structural steels under complex exposure to laser radiation

The purpose of the work was to study the effect of laser microstructuring modes of the cutting edge on changes in the structure and mechanical properties of the surface layer of parts made of hot-rolled structural carbon steels grades 20, 35, 45. Methods. Structural carbon steels of grades 20, 35, 45 were selected as objects of research. To study the effect of laser modification on changing the structure and mechanical properties of machine parts using laser cutting, special samples were made in the form of square plates (35×35 mm) with a thickness of 2 mm (St20 and St45) and 4 mm (St35). After laser cutting according to the modes, one of the sides of the sample was subjected to mechanical grinding in order to remove a layer with a modified structure of the material obtained during laser cutting. Next, laser microstructuring of the sample surfaces was performed using a continuous fiber laser. Metallographic and durometric studies were carried out to study the effect of laser microstructuring on changes in the structure and properties of the surface layer. Results. The regularities of the structure of the zone of laser action of structural carbon steels after laser microstructuring have been revealed, which consists of two layers: a non-etching (slightly etching) white layer, which is a finely dispersed martensite of a needle structure and immediately following it a zone of thermal influence, which, depending on the carbon content in the steel, has a different structure: ferrite-pearlite, martensitic, troostomartensitic, martensiticpearlitic. It has been established that laser microstructuring of a pre-polished surface in some cases leads to an increase in the values of microhardness and the length of the laser exposure zone, which may be associated with an increase in the absorption capacity of the material of the polished surface and, accordingly, a decrease in its reflectivity. Conclusion. The results obtained can be used in the creation of resource-saving material processing processes.

تحضير ودراسة اللايكوبين الطبيعي والنانوي في تثبيط نمو الخلايا السرطانية خارج الجسم الحي In vitro

The effectiveness of both natural and nano-lycopene extracted from tomato waste powder in affecting the growth of cancer cells outside the body was studied. The study included the preparation of natural lycopene extract, using the triple mixture of hexane, acetone, and ethanol in proportions 2:1:1 and drying it, then preparing the nanocomposite using the high-energy mechanical grinding technique, and its dimensions were estimated using a Scanning Electron Microscope (SEM) and which was 78nm, and the effectiveness of the two preparations was tested in Inhibition of cancer cell lines of the human mouth and skin, during three periods of time 12, 24, 72 h and at concentrations of both natural and nano-lycopene 0.0,150, 300, 600, 1200, 2400 micrograms/ml, the results of the study showed There was a significant inhibitory effect p≤0.05. for both natural and nano-lycopene in the growth of cancer cells, and nano-lycopene was significantly superior to natural lycopene for skin and mouth models, and the inhibition effect of cancer cells increased for both natural and nano-lycopene with increasing concentration and period, and the highest percentage of inhibition for natural lycopene was 71% and 79.8% While the highest percentage of inhibition for nanoscale icon was 85.2% and 93.1% at a concentration of 2400 µg/ml for 72 h and for skin and oral cancer cell lines, respectively.

Anodic Production and Characterization of Biomimetic Oxide Layers on Grade 4 Titanium for Medical Applications.

Biomaterials are the basis for the development of medicine because they allow safe contact with a living organism. The aim of this work was to produce innovative oxide layers with a microporous structure on the surface of commercially pure titanium Grade 4 (CpTi G4) and to characterize their properties as drug carriers. The anodization of the CpTi G4 subjected to mechanical grinding and electrochemical polishing was carried out in a solution of 1M ethylene glycol with the addition of 40 g of ammonium fluoride at a voltage of 20 V for 2, 18, 24, and 48 h at room temperature. It was found that the longer the anodization time, the greater the number of pores formed on the CpTi G4 surface as revealed using the FE-SEM method, and the greater the surface roughness determined in profilometric tests. As the anodizing time increases, the amount of the drug in the form of gentamicin sulfate incorporated into the resulting pores decreases. The most favorable drug release kinetics profile determined via UV-VIS absorption spectroscopy was found for the CpTi G4 anodized for 2 h.

Tetraphenylethene-based mononuclear aggregation-induced emission (AIE)-active mechanofluorochromism gold(I) complexes with different auxiliary ligands

In this study, a series of tetraphenylethene-containing gold(I) complexes with different auxiliary ligands have been synthesized. These complexes were characterized using a variety of techniques including nuclear magnetic resonance spectroscopy, mass spectrometry, and single crystal X-ray diffraction. Their aggregation-induced emission (AIE) behaviors were investigated through ultraviolet/visible and photoluminescence spectrum analyses, and dynamic light scattering measurements. Meanwhile, their mechanofluorochromic properties were also studied via solid-state photoluminescence spectroscopy. Intriguingly, all these mononuclear gold(I) molecules functionalized by tetraphenylethene group demonstrated AIE phenomena. Furthermore, five gold(I) complexes possessing diverse auxiliary ligands exhibited distinct fluorescence changes in response to mechanical grinding. For luminogens 2–5, their solids showed reversible mechanofluorochromic behaviors triggered by the mutual transformation of crystalline and amorphous states, while for luminogen 1, blue-green-cyan three-color solid fluorescence conversion was realized by sequential mechanical grinding and solvent fumigation. Based on this stimuli-responsive tricolored fluorescence feature of 1, an information encryption system was successfully constructed.

Production and comparison of structural, thermal and physical characteristics of chitin nanoparticles obtained by different methods

This study examined the impact of acid hydrolysis, tempo oxidation, and mechanical grinding on the physical, thermal, and structural properties of α-chitin nanocrystals and nanofibers. The manufacturing methods could influence the diameter, functional groups, and crystal patterns of the resulting nanoparticles. Analysis of the DLS results revealed that the size of acidic nanocrystals were smaller and showed improved dispersibility. The XRD patterns indicated that the chemical and mechanical treatments did not alter the crystalline arrangement of the α-chitin. FT-IR spectra analysis revealed that the chemical and mechanical methods did not affect the functional groups of the nanoparticles. DSC results showed that the nanoparticles had good thermal stability up to 400 °C, and it was found that the nanofibers had better thermal resistance due to their longer length. In the FE-SEM images, the nanoparticles were observed as fiber mats with a length of more than 100 nm. It was also found that the diameter of the nanoparticles was less than 100 nm.

Pickering emulsion stabilized by cellulose nanofibril from pineapple leaves for biofoam manufacture

Cellulose nano fibril (CNF) can be selected as an agent of pickering emulsion in biofoam manufacture. This study thoroughly investigates the pickering emulsion method for producing biofoam, the characterization of CNF from pineapple leaves, the production of biofoam with various concentration of CNF and surfactant, and the effect of these parameters on the properties of wet foam and dry foam. CNF was created by mechanical grinding then the stability and morphology were evaluated. The pickering emulsion mechanism in biofoam manufacture was investigated using foamability and foam stability with various CNF and surfactant concentration. As the results, CNF concentrations will create varying zeta potential values. The morphology of CNF shows that it has a structure-like entangled network. The stability test demonstrates that adding CNF improves the stability and foamability of biofoam by the pickering effect. Biofoam without CNF has an unstable structure and is easily collapse when dried in an oven. The concentration of CNF and the amount of surfactant utilized altered the qualities of both wet and dry foam. The lower concentration of CNF and the addition of surfactant could increases foamability, high porosity, water absorption, and biodegradability; as well as low density, contact angle and bending characteristics. In biofoam that consists of 2 % CNF, the stability of wet foam increases as the amount of surfactant added, resulting in a biofoam with low tensile strength.

Porphyrin/Fullerene Porous Molecular Cocrystal Featuring a Robust One-Dimensional Channel.

Microporous molecular crystals are promising materials because of their designable porosity as well as their resistance to chemical and other stimuli. Here, we developed microporous molecular cocrystals by taking advantage of the specific interactions between porphyrins and fullerene molecules. Single-crystal X-ray diffraction analysis revealed that one nickel(II) porphyrin interacts with two fullerene molecules to form a two-dimensional honeycomb network with an eclipsed stacking mode, providing one-dimensional void channels. After the pores were activated by heat treatment or mechanical grinding, the prepared cocrystal can incorporate gas and solvent molecules reversibly while maintaining its single-crystallinity. Also, it retained its single-crystallinity in the presence of water, acid-base, or high pressure. These findings in this study expand the availability of molecular crystals based on intermolecular interactions as porous materials, which are expected to work under conditions that have not been applicable to other molecule-based porous materials.

Construction of composites for medical purpose based on pyrogenic silica with immobilized succinic acid and their properties

The work is aimed at creating new, more effective drugs containing succinic acid. For this purpose, a methodology has been developed for transferring the active substance to a nano-sized state, in which the acid, due to an increase in its outer surface, is in the form of clusters, which, upon contact with the mucous membrane, can be more easily absorbed by the body. A complex of physicochemical methods was used to study the effect of immobilization of Succinic Acid (SA) on the surface of hydrophilic, hydrophobic silica and their mixtures on the existing specific surface area and the state of the adsorption layer. It has been shown that during the joint mechanical grinding of crystalline succinic acid with silicas, composite systems are formed in which it is uniformly distributed in the interparticle gaps of silicas and is in the form of nanosized predominantly amorphous clusters. For silicas and their mixtures, the signal of acid crystallites is also fixed on the X-ray diffraction patterns. Additional mechanical treatment of composites with water practically does not change the ratio of amorphous and crystalline components of succinic acid in the surface layer, which indicates its poor solubility in clustered water. This is also confirmed by liquid NMR data, according to which there is no signal from the methylene groups of succinic acid in the spectra. All composites, regardless of the content of SA, treatment with water, and the ratio of the hydrophobic and hydrophilic components, retain a high adsorption capacity with respect to nitrogen. The BET-specific surface of the composites remains at the level of 150 - 200 m2/g. Hydrated forms of hydrophobic silica AM-1 retain the ability to interact with non-polar substances. Using chloroform as an example, it was shown that even at h = 1 g/g, chloroform displaces part of the water from the interparticle space, which manifests itself in a decrease in the interfacial energy of water due to the formation of surface water clusters with a large radius. The hydrophobic silica surface stabilizes the weakly associated form of water, the amount of which can reach 20 mg/g.

Multi-stimuli-responsive luminescent switching properties of cycloplatinated(II) complexes bearing 2-phenylpyridine derivatives

Three new cycloplatinated(II) complexes, Pt(ppy)L (1), Pt[(CF3)ppy]L (2) and Pt[dF(CF3)ppy]L (3) based on 2-phenylpyridine (ppy), 2-phenyl-5-(trifluoromethyl)pyridine [(CF3)ppy], 2-(2,4-Difluorophenyl)-5-(trifluoromethyl)pyridine [dF(CF3)ppy] and 4-[2-(4-fluorophenyl)ethynyl]-2-pyridinecarboxylic acid (L) ligands were synthesized and characterized. Complex 1 has one metastable structure and exhibits reversible mechanoluminescent property. On the contrary, complexes 2 and 3 each have five types of metastable structures and exhibit multi-stimuli-responsive luminescent switching properties triggered by VOC vapors absorption, heating, and mechanical grinding. Moreover, complexes 2 and 3 display a series of untraditional luminescent switching behaviors such as two-step conversion processes, irreversible process and more than one thermally stable products. Systematic studies on crystal structure, luminescence spectra, PXRD and DFT theoretical calculation demonstrate that the luminescent switching properties of these complexes are attributed to the formation/elimination of intermolecular Pt-Pt interactions during structural conversion processes between metastable structures, which lead to the transformation of the lowest energy excited states between MLCT and MMLCT transitions. Furthermore, the unconventional luminescent switching behaviors are due to the high stability of the metastable structures. In addition, the studies also reveal that the stacking structure of complex can affect its luminescent switching behavior, while the good molecular planarity of the complex is not conducive to the luminescent switching properties.

Formation of Surface Deformed Layer of AZ31 Magnesium Alloy Subjected to Conventional Mechanical Grinding

Formation of Surface Deformed Layer of AZ31 Magnesium Alloy Subjected to Conventional Mechanical Grinding

Enhanced lithium battery cathode performance via mechanical grinding of CFx_MnO2 hybrid materials for space-grade applications: Unveiling synergistic effects

CFx_MnO2 hybrid cathode materials are prepared from a (C2F)n-type graphite fluoride (CFx) and industrial MnO2. Because of its physicochemical (insulating behavior, low content of CF2 and CF3 groups, no or a few remaining sp2 carbon atoms) and electrochemical properties (flat plateau on galvanostatic curve and theoretical capacity of 623 mAh/g, higher than other conventional cathodes for primary lithium battery), graphite fluoride of (C2F)n-type is selected to evidence synergetic effects with MnO2 that occur at the fluoride/oxide and electrolyte/ electrode interfaces. Both materials are mixed by mechanical ball-milling using different sets of parameters. The hybrid material presents very good electrochemical properties with a maximum energy density of about 1600 Wh per kg of active material. Notably, it shows a considerable improvement in voltage plateau and voltage delay compared to CFx. The parameters applied during ball-milling also shape the electrochemical performance of the new hybrid material. Ball milling increases the average discharge voltage plateau, and the power density of the battery, and avoids ohmic drop which may cause a battery to be eliminated as soon as it begins to discharge. More finely, electrochemical impedance spectroscopy shows that pushed grinding leads to more homogeneous but more polarized material-electrolyte interfaces so better diffusion and capacity but lower discharge potential.

Novel n–n Type CoCr2O4/NiFe2O4 Heterojunction Photocatalyst: Internal Magnetic Field Control of Photocatalytic Activity, Mechanism Insight and Pathway for Tetracycline Hydrochloride Degradation

AbstractHerein, a series of CoCr2O4/wt%NiFe2O4(CCO/wt%NFO) composites are successfully synthesized by a simple solution combustion method combined with mechanical grinding techniques. The preparation of CCO/wt%NFO composites result in an estimation of its photocatalysis performance by removing tetracycline hydrochloride (TC) as a model of antibiotic pollutants. The results show that the percentage of NFO by mass have a great influence on the morphology and the photocatalysis performance of CCO/wt%NFO composites. Superior photocatalysis performance is observed in CCO/25%NFO composites prepared at percentage of NFO is 25%. The photocatalyst used with CCO/25%NFO composites result in a removal ratio of 81% for TC. The generation of hydroxyl radical (•OH), superoxide anion radical (•O2−) and holes (h+) is largely responsible for degrading TC through photocatalysis in the presence of CCO/wt%NFO composites. The optimal operating conditions involve the initial concentration of TC and pH of TC being 50 mg L−1 and pH = 13, respectively. Furthermore, CCO/wt%NFO is highly reusable and stable during the photocatalytic removal process. The degradation pathway, toxicity, and photocatalytic mechanism of CCO/25%NFO composites for the degradation of TC are extensively examined through mass spectrometry, toxicity analysis, and energy band theory.

Effects of Misalignment of c-axis on the Properties of Hydrogenation-Disproportionation-Desorption-Recombination Particles.

Hydrogenation-Disproportionation-Desorption-Recombination (HDDR) Nd2Fe14B particles have excellent magnetic properties, but the magnetic properties of powder are not uniform across different particle sizes. The remanence and maximum magnetic energy products of samples with a particle size of 120 μm are 14.0 kGs and 41.35 MGOe, while the products of samples with a particle size of 60 μm are only 13.3 kGs and 36.31 MGOe. The macroscopic morphology of HDDR Nd2Fe14B particles and the gradient distribution of microstructures in different micro-regions were observed. By modifying the macroscopic morphology of the particles, the poorly oriented clusters on the surface of the particles were precisely eliminated, and the remanence and maximum magnetic energy products of the particles increased to 14.5 kGs and 45 MGOe, respectively. Compared with the original particles, the samples after mechanical grinding had better grain arrangement. The effects of the nanocrystalline c-axis and field misalignment angle θ on the magnetic properties of HDDR Nd2Fe14B particles were investigated through micromagnetic simulation. The targeted removal of macroscopic defects on the particle surface contributed to a 3.6% increase in remanence and an 8.8% increase in the maximum magnetic energy product, offering a promising approach to enhance the microstructure of high-performance HDDR Nd2Fe14B particles.

Dual Z-scheme heterojunction Ce2Sn2O7/Ag3PO4/V@g-C3N4 for increased photocatalytic degradation of the food additive tartrazine, in the presence of persulfate: Kinetics, toxicity, and density functional theory studies

This study involved the synthesis of a Ce2Sn2O7/Ag3PO4/V@g-C3N4 composite through hydrothermal methods, followed by mechanical grinding. The resulting heterojunction exhibited improved catalytic activity under visible light by effectively separating electrons and holes (e−/h+). The degradation of Tartrazine (TTZ) reached 93.20% within 50 min by employing a ternary composite at a concentration of 10 mg L−1, along with 6 mg L−1 of PS. The highest pseudo-first-order kinetic constant (0.1273 min−1 and R2 = 0.951) was observed in this system. The dual Z-scheme heterojunction is developed by Ce2Sn2O7, Ag3PO4, and V@g-C3N4, and it may increase the visible light absorption range while also accelerating charge carrier transfer and separation between catalysts. The analysis of the vulnerability positions and degradation pathways of TTZ involved the utilization of density functional theory (DFT) and gas chromatography-mass spectrometry (GC-MS) to examine the intermediate products. Therefore, Ce2Sn2O7/Ag3PO4/V@g-C3N4 is an excellent ternary nanocomposite for the remediation of pollutants.

Mechanical recycling of CFRPs based on thermoplastic acrylic resin with the addition of carbon nanotubes

Carbon fibre-reinforced polymers (CFRPs) are commonly used in aviation, automotive and renewable energy markets, which are constantly growing. Increasing the production of composite parts leads to increased waste production and a future increase in end-of-life components. To improve the recyclability of CFRPs, new materials that fit in with the idea of a circular economy should be used as a composite matrix. One such material is a commercially available thermoplastic liquid resin, Elium® (Arkema, France). In this work, the authors investigated how the mechanical recycling process affects the properties of thermoplastic-based carbon fibre composites. CFRPs with neat Elium® resin and resin modified with 0.02 wt.% single-walled carbon nanotubes or 0.02 wt.% multi-walled carbon nanotubes were manufactured using the resin infusion process. Afterwards, prepared laminates were mechanically ground, and a new set of composites was manufactured by thermopressing. The microstructure, mechanical, thermal and electrical properties were investigated for both sets of composites. The results showed that mechanical grinding and thermopressing processes lead to a significant increase in the electrical conductivity of composites. Additionally, a sharp decrease in all mechanical properties was observed.

Mechano-responsive and acid stimuli-responsive luminescence of a hydrogen-bonded organic frameworks

Stimuli-responsive materials are capable of changing their chemical or physical properties when exposed to external stimuli, showing a wide range of potential applications such as drug delivery, sensing, smart coatings, and artificial muscles. Here, a micron-sized hydrogen-bonded organic framework PFC-1 was constructed and its mechanical and acid stimuli-responsive luminescence were investigated. It was found that the fluorescence of PFC-1 aqueous suspension is affected HCl concentrations. The pristine PFC-1 aqueous suspension exhibits an emission peak with high fluorescence intensity at 440 nm and two weak emission shoulders at 475 nm and 535 nm, respectively. Upon the addition of hydrochloric acid, there is a gradual reduction in the peak intensities at 440 nm and 475 nm, while the peak intensity at 535 nm remains relatively unchanged, resulting in a progressive shift in fluorescence color from blue to green. Mechanical grinding induces approximate 30 nm blue-shift in the fluorescence emission peak, a change that is reversible upon immersing the powder in ethanol for 60 min. This work contributes to the development of stimuli-responsive hydrogen-bonded organic framework materials with potential applications in acid and pressure fluorescence sensing.