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The research was conducted to develop and assess the performance of composite grinding wheels enhanced with a graphite additive. These composite wheels were composed of aluminum oxide as abrasive and reinforcement material, E-glass as a reinforcement material, and phenolic resin as the matrix material. Various concentrations of graphite (4%, 8%, 12%, and 16% by weight) were incorporated into the composite formulations. Aluminum oxide, phenolic resin, and graphite were hand-stirred and combined. The mixture was then compressed at 94.4 MPa at room temperature, followed by heat treatment at 204°C for 50 min. The incorporation of graphite into Al2O3/E-glass/phenol formaldehyde composite grinding wheels significantly enhanced their mechanical properties and grinding performance. Increasing the graphite content up to 12 wt% in grinding wheels (GW3) resulted in a steady increase in density (from 1.9 g/cm³ to 2.1 g/cm³) and a corresponding decrease in porosity (from 16.5% to 3.6%) compared to the 4 wt% graphite-filled grinding wheels (GW1). Moreover, GW3 showed improvements in push-out strength by 60.6% (from 4.1 MPa to 6.57 MPa) and compressive strength by 15.7% (from 21.8 MPa to 25.17 MPa) compared to GW1. Wheels containing 16 wt% graphite (GW4) exhibited the lowest wear rate, reducing it by 89% (from 0.105 g/cm2 to 0.019 g/cm2) compared to GW1. These findings suggest that graphite incorporation is a promising approach for developing more durable and efficient grinding wheels, with the optimal graphite content for balancing strength and wear being 12 wt%. [ABSTRACT FROM AUTHOR]

As-built additively manufactured components for heat exchanger applications, suffer from high surface roughness. In this study, a novel ultrasonic-assisted electropolishing setup is designed and tested to reduce the internal surface roughness of a Laser Powder Bed Fusion (L-PBF) additively manufactured copper (GRCop-42) heat exchanger component. In the electropolishing setup, the surface of the as-built heat exchanger is used as the anode while a bulk copper rod is used as the cathode. An electropolishing fluid consisting of CuCl2, HCl, and SiC abrasive particles was used as electrolyte media, along with ultrasonication. The effect of chemical constituents, ultrasonic duration, and abrasive particles on surface roughness reduction was studied. It was observed that the ultrasonic agitation condition assisted with the abrasive particles was beneficial to reduce the surface roughness of the heat exchanger sample (over 50%) through acoustic streaming and scrubbing effect. An addition of 1% bio-based trihexyltetradecyl phosphonium saccharinate ionic liquid improved the corrosion properties for the copper surface. Overall, to reduce the roughness of L-PBF additively manufactured samples of complicated shapes with internal features, this process could be a viable technique, where mechanical polishing is not possible and internal surfaces are not accessible. [ABSTRACT FROM AUTHOR]

A lanthanum–cerium-based abrasive composed of CeO2, LaOF, and LaF3 was commercially obtained. The effect of sodium hexametaphosphate (SHMP) on powder dispersion behavior was systematically investigated using the combined techniques of liquid contact angle, turbidity, zeta potential (ZP), scanning electron microscopy (SEM), powder X-ray diffraction (XRD) combined with Rietveld refinements, X-ray photoelectron spectroscopy (XPS), and polishing tests. The results indicated that the addition of 0.5 wt.% SHMP dispersant to the 5 wt.% lanthanum–cerium-based slurry produced the most stable suspension with a high turbidity of 2715 NTU and a low wetting angle of 45°. The as-obtained slurry displayed good surface polishing quality for K9 glass, with low surface roughness (Ra) of 0.642 and 0.515 nm (in the range of 979 × 979 μm2) at pH = 6 and 11, respectively, which corresponds to the fact that it has local maximum absolute values of ZP at these two pH values. SEM images demonstrated that after appropriate grafting of SHMP, the particle aggregation was reduced and the slurry's dispersion stability was improved. In addition, the dispersion mechanism was explained based on the principle of complexation reaction, which reveals that the dispersant SHMP can increase the interparticle steric hindrance and electrostatic repulsions. In an acidic environment, steric hindrance dominates, while electrostatic repulsion prevails under alkaline conditions. As expected, this polishing slurry may find potential applications in manufacturing optical devices and integrated circuits. [ABSTRACT FROM AUTHOR]

Abrasive Flow Machining (AFM) is highly effective for precise surface control and finishing. The process's material removal mechanism significantly impacts surface quality, especially in complex parts. However, little research addresses how initial micro-surface textures affect AFM outcomes. This study prepared four types of initial surface profiles and machined them using various abrasive media particle sizes. The rheology of the abrasive media was analyzed, with a custom guide restricting the fluid domain to create gradient flow changes. Both experimental and simulated one-way and two-way AFM processes were conducted. Results demonstrated that the material removal efficiency improved according to an enhanced version of Preston's equation for flat surfaces. Initial surface textures exerted more influence on material removal than anticipated. All abrasive media sizes yielded uniform surface quality, with surface roughness improvements exceeding 80%. Larger initial surface textures experienced greater material removal. Chemical element analysis confirmed the AFM process is contamination-free. [ABSTRACT FROM AUTHOR]

Laser surface alloying is a method used to modify a metal surface to produce a thin surface layer with improved mechanical properties. The results of tests on surface carburizing and boriding of steel 20 using a laser beam are presented. Before laser irradiation, the surface of the material was coated. Two types of coating were used: suspensions of graphite powder and boron carbide. Steel 20 was carburized and borided by melting the coating and the substrate. This processing produced various microstructures in the surface layer, depending on the type of coating used and the processing parameters. The microhardness of the alloyed layers was measured along the depth axis. The surface layer consists of an alloying zone and a heat-affected zone. Some specimens carburized by surface alloying displayed cracking and porosity due to carbon enrichment and high solidification rates. The laser-borated surface has a remelting zone consisting of an eutectic mixture of iron borides FeB, Fe2B, and Fe3B. The dense boride zone located near the surface, while the content of the eutectic mixture of borides and martensite increased toward the base metal. The microhardness of the borated layer was 1200 HV. The alloy layers were tested for abrasive wear. [ABSTRACT FROM AUTHOR]

These days, metal matrix composites (MMCs) are being widely utilized in automotive and aerospace industries as prominent alternatives to traditional materials. Owing to their elevated strength-to-weight proportion, exceptional fracture toughness, and lightweight design, they can be used in a variety of applications. MMCs undergo extensive machining while making parts and components out of them. The machining of monolithic materials, such as metals and alloys, is a widely used and established process in different industries, such as the aerospace, bio-medical, and automotive sectors. Because of the properties of the metal matrix and the strong reinforcement, MMCs provide unique challenges. Modern machining processes have been found to be superior in overcoming challenges and achieving improved machinability of MMCs. An overview of MMC machining with modern methods is provided in this article. This article first outlines MMCs and addresses the need for and difficulties associated with their machining. Next, it reviews previous investigations on the machining of MMCs employing modern methods like electrical discharge machining, laser machining, abrasive machining, and hybrid machining. Productivity and surface integrity issues, including delamination and roughness, etc., are discussed. When presenting the review, the benefits and drawbacks of modern processes are also taken into account. [ABSTRACT FROM AUTHOR]

This study proposes a multi-objective optimization method based on a hybrid of computational fluid dynamics (CFD) and experimental techniques, which integrates a weighted average surrogate model and the NSGA-II intelligent algorithm. To validate the feasibility of this method, structural optimization for the self-excited oscillation mixer (SEOM) was conducted. The optimization objectives aimed to reduce potential abrasives accumulation in the mixed-flow cavity and minimize erosion on the elbow of the slurry outlet caused by mixed slurry, thereby enhancing the service life and rust removal efficiency of the mixed flow rotary jet descaling (MFD). A comparison between the optimized model and original model revealed a 2.51% increase in negative pressure within the cavity of the optimized model, as well as a 10.36% decrease in velocity at the outlet of mixed slurry based on simulation results. Experimental methods measured both mass flow rate of inhaled abrasive particles and impact force of mixed slurry outlet. The experimental results demonstrated that compared to its original counterpart, the optimized model exhibited superior performance with a 22.81% increase in abrasive particle flow rate and an 11.34% reduction in mixed slurry impact force indirectly, verifying better simulation effectiveness for SEOM with optimized structure. This approach also enhanced efficiency and surface quality of MFD processing strip steel, providing guidance for structural optimization of similar SEOMs used in mixed flow descaling. [ABSTRACT FROM AUTHOR]

Super-reduced phases (SRPs), such as silicon carbide (SiC) and metal silicides, have increasingly been reported in various geological environments. However, their origin remains controversial. SRP inclusions (e.g., metal silicides and metallic silicon (Si0)) within SiC are commonly believed to indicate a natural origin. Here, we identified an unusual SRP assemblage (SiC, (Fe,Ni)Si2, and Si0) in situ in an H5-type Jingshan ordinary chondrite. Simultaneously, our analysis showed that the SiC abrasives contain (Fe,Ni)Si2 and Si0 inclusions. Other inclusions in the artificial SiC were similar to those in natural SiC (moissanite) reported in reference data, including diverse metal silicides (e.g., FeSi, FeSi2, Fe3Si7, and Fe5Si3), as well as a light rare earth element-enriched SiO phase and Fe-Mn-Cr alloys. These inclusions were produced by the in situ reduction of silica and the interaction between Si-containing coke and hot metals during the synthesis of the SiC abrasives. The results demonstrate that the SRP assemblage in the Jingshan chondrite originates from abrasive contamination and that the SRP inclusions (with a low content of Ca, Al, Ti, and Zr) cannot be used as a conclusive indicator for natural SiC. Additionally, the morphologies, biaxiality, and polytypes (determined by Raman spectroscopy) of SiC abrasives bear resemblance to those reported for natural SiC, and caution must be exercised when identifying the origin of SRP in samples processed by conventional methods using SiC abrasives. At the end of this paper, we propose more direct and reliable methods for distinguishing between natural and synthetic SiC. [ABSTRACT FROM AUTHOR]

In order to evaluate the abrasive belt grinding performance, this paper proposes to conduct nickel-based superalloy robot abrasive belt grinding experiment based on different types of abrasive belts with multiple grit sizes. First, the single grinding performance evaluation is performed through five performance parameters: material removal rate, surface roughness, tangential force, specific grinding energy, and specific wear height. Then, based on the evaluation results of single grinding performance, a weighted evaluation function is established to comprehensively evaluate the grinding performance. It is found that the structured abrasive belt has relatively better grinding performance. The main factors affecting the abrasive belt grinding performance are identified through the evaluation results, with the effect of grit size being more significant. In addition, this paper analyzes the characteristics of material deformation based on the grinding subsurface microstructure, and discusses the effects of abrasive belts on material deformation. [ABSTRACT FROM AUTHOR]

The analysis of the defects of parts of the friction units of aviation equipment under the conditions of abrasive wear was carried out. Types of electrode materials for modification of parts by electrospark alloying are considered. The mechanisms of wear under the influence of free abrasive of electrospark coatings of 1.1645 and 1.3355 steels, HG30 alloy and ZLAB-1 ceramics on structural steels 30HGSA and 45 were analyzed. The dependence of the intensity of wear of electrospark coatings on the hardness of carbides and borides and the ratio of the strengthening phase in the matrix was determined. The low wear resistance of the ceramic coating ZLAB-1 is due to the presence of the boride component ZrB2 of increased microhardness in the matrix phase, which leads to the brittleness of the coating. The predominance of brittle fracture of ESC of 1.1645 steel is caused by the presence of iron carbide up to 16% in the structure of secondary cementite and pearlite of the steel. The increase in wear resistance of ESC made of 1.3355steel is due to the presence of a large amount of W, V and Mo carbides. The phase inhomogeneity of ESC made of HG30 alloy, established by X- ray structural and phase analysis of the coating diffractograms and the activation of oxidation processes during friction lead to an increase in the wear resistance of ESC due to the appearance of W2C tungsten semi-carbide and WC1-x tungsten semi-carbide phases. The obtained results indicate the prospects of ESC made of 1.3355 steel and HG30 alloy with the necessary level of properties to increase the wear resistance of structural steels. [ABSTRACT FROM AUTHOR]

In this work, it is proposed to carry out a chemical–thermal synthesis of stable interatomic bonds between the atoms of copper slag particles and a carbon-containing substance, thereby obtaining a silicon carbide compound in the abrasive' surface layer, which will increase the abrasive particle surface layer's strength for waterjet cutting. [ABSTRACT FROM AUTHOR]

This study presents an unconventional flow processing technique that uses glass microspheres instead of abrasives. The fundamentals of flow machining with glass microspheres, including microsphere flow burnishing (MFB) and the conditions necessary for cutting or plastic deformation of a surface to occur during MFB, are determined. Details on such conditions are lacking, and therefore, this study attempts to define these conditions. To this end, MFB was experimentally confirmed to be a burnishing process, and the effects of MFB and abrasive flow machining (AFM) on 2017A aluminum alloy were compared. Both processes achieved a surface roughness (Sa) of < 0.5 μm, while MFB yielded higher values of surface microhardness and compressive stress. The effects of basic process parameters on the MFB and AFM results (workpiece weight loss and Sa) were compared experimentally, and the corresponding mathematical models were established. Utilizing these relationships, MFB parameters can be selected so as to obtain the most favorable surface layer for the expected operating conditions. [ABSTRACT FROM AUTHOR]

At present, Gongchangling mill plant uses the traditional "three stages crushing with one closed", "grinding in stages" process, which had the problems of long production process and high energy consumption of grinding. Therefore, it was proposed to increase the (semi-) autogenous-grinding operation after primary crushing, reduce the particle size of the materials entering the ball mill, in order to reduce the energy consumption of the grinding operation, optimize the grinding process, increase the production capacity of the plant, and reduce the production cost of the grinding operation. The Fe grade of the raw ore material for the test was 28.27%, in which iron mainly existed in the form of magnetite, and the gangue was mainly SiO2 with a content of 48.61%. JK drop weight test for the primary crushed products and Bond ball mill work index test for the tertiary crushed products in the operation flowsheet of Angang Gongchangiing Concentration Plant were conducted to obtain the parameters of crushing and milling characteristics of the ore. The results showed that the impact crushing model of rock was t10 = 70.099 X (1-exp-0.647XEcs), where A was the impact comminution parameter and is value was 70.099, 3 was 0.647 and AXb was 45.354, the impact crushing resistance of the ore was of medium level and increases with the decrease of particle size. The ore abrasion coefficient ta = 0. 361, and the abrasion resistance was in medium level. The relative density of ore was 3.26. The raw ore ball mill work index Wib = 11.7665 kWh/t obtained by Bond ball mill work index F80 test belonged to medium hard ore and suitable for adopting a (semi-) autogenous-grinding process. The feed size of the semi-autogenous mill was 160 mm, and the product size 780 was 86 µm. The simulation results of JKsimMet software showed that two sem-autogenous mills with Φ8.8 mX5.1 m (installed power 7 000 kW) were needed to meet the production requirements. The results of this test were important for the optimization of the process flowsheet of the subsequent processing plan. [ABSTRACT FROM AUTHOR]

Natural fiber hybrid composites are replacing synthetic fiber composites, which improves environmental cleanliness. In this investigation, a compression molding process was used to produce a Banana/Sisal Hybrid Composite (BSHC) and the influence of Abrasive Water Jet Machining (AWJM) process parameters on surface quality was studied. The AWJM experiments were conducted using the design of experiment techniques, with parameters such as water pressure (P), nozzle transfer speed (d), and standoff distance (s). During the AWJM process, P was identified as the most significant parameter influencing surface quality. The optimum machining parameters (P3, d1, s1) provide better surface quality which produces a surface roughness of 10.1 μm. The experimental surface roughness values have a better correlation with the predicted surface roughness which shows the efficiency of the prediction model. [ABSTRACT FROM AUTHOR]

The structure and properties of deposited layers with a self-fluxing PG-10N-01 alloy of the NiCrBSi system, which is modified with composite material obtained by self-propagating high-temperature synthesis, were studied. Powders of titanium, technical carbon, refractory clay, aluminum, iron oxide, and PT-NA-01 thermosetting powder are used as the initial components of the modifying composite material. The powders were mechanically activated in a ball mill, pressed into a cylindrical sample, and then subjected to the process of self-propagating high-temperature synthesis. The deposition of the samples was carried out with a non-fusible graphite electrode with a diameter of 9.5 mm, at a current of 110 A, using an inverter power source SV-290NK. It was established that the structure of the layer deposited with the PG-10N-01 alloy consists of a solid solution based on nickel (γ-Ni) and a eutectic formed on its basis with Ni3B boride. Single inclusions of carbides of chromium Cr3C2 and boron B4C were also detected in the deposited layer. When adding a modifying composite material to the PG-10N-01 alloy, the structure of the deposited layer consists of γ-hard solution and eutectics, strengthened by carbides of titanium TiC and silicon SiC, which increase the microhardness and wear resistance of the layer. The microhardness of the layer deposited with the composite material, which contained 10% of the modifying component, is 660 HV, which exceeds the microhardness of the layer deposited with the PG-10N-01 alloy, which is equal to 510 HV. Based on the results of the research, operational tests of the set of duckfoot blades of the KPP-8 semi-trailer cultivator, aggregated with the New Holland T 6090 tractor, were carried out in the conditions of the Kamianuvatka farm (Novoukrainka district, Kirovohrad region). Based on the tests, it was proved that the relative wear resistance of duckfoot blades made of 65G steel, strengthened on the reverse side according to the "toe-working blade" scheme by depositing a layer of composite material is 1.7 times greater compared to the wear resistance of blades made by standard technology logic.

A lanthanum–cerium-based abrasive composed of CeO2, LaOF, and LaF3 was commercially obtained. The effect of sodium hexametaphosphate (SHMP) on powder dispersion behavior was systematically investigated using the combined techniques of liquid contact angle, turbidity, zeta potential (ZP), scanning electron microscopy (SEM), powder X-ray diffraction (XRD) combined with Rietveld refinements, X-ray photoelectron spectroscopy (XPS), and polishing tests. The results indicated that the addition of 0.5 wt.% SHMP dispersant to the 5 wt.% lanthanum–cerium-based slurry produced the most stable suspension with a high turbidity of 2715 NTU and a low wetting angle of 45°. The as-obtained slurry displayed good surface polishing quality for K9 glass, with low surface roughness (Ra) of 0.642 and 0.515 nm (in the range of 979 × 979 μm2) at pH = 6 and 11, respectively, which corresponds to the fact that it has local maximum absolute values of ZP at these two pH values. SEM images demonstrated that after appropriate grafting of SHMP, the particle aggregation was reduced and the slurry’s dispersion stability was improved. In addition, the dispersion mechanism was explained based on the principle of complexation reaction, which reveals that the dispersant SHMP can increase the interparticle steric hindrance and electrostatic repulsions. In an acidic environment, steric hindrance dominates, while electrostatic repulsion prevails under alkaline conditions. As expected, this polishing slurry may find potential applications in manufacturing optical devices and integrated circuits.

Tribological properties are the significant factors to evaluate the application of polycrystalline cubic boron nitride(PcBN) with hard materials in vacuum conditions. In the current paper, the tribological properties of PcBN and WC-Co cemented carbide (YG8) during the sliding process are carried out under different loads in vacuum by ball-disk friction and wear experiments. The wear tracks of PcBN and wear scars of YG8 were characterized. The results show that the wear mechanisms of PcBN in vacuum are mainly abrasive wear and adhesive wear. Furthermore, furrows are also detected on the surface of YG8 balls due to the plowing of exfoliated cubic boron nitride. As a result, abrasive wear is the failure form of YG8 ball. The average CoF is negatively correlated with the loads. Moreover, the relationship between friction and wear is discussed deeply. The wear rate of YG8 ball is positively correlated with the load. Additionally, the wear rate ratio of PcBN and YG8 indicates that higher loads can promote the wear rate of YG8, but it also leads to the rapid wear of PcBN. The results could provide significant instructions for the regulation and control of the tribological properties of PcBN in the coming outer space exploration activities. [ABSTRACT FROM AUTHOR]

In order to reveal the material removal behavior of robot abrasive belt grinding (RABG) of nickel-based superalloy, the experimental research method of single grit grinding is proposed. In the research, ceramic alumina grits are used to scratch superalloy K438 based on the experimental setup of RABG. Four material removal parameters, namely real cutting depth, number of cutting edges involved in grinding, effective cutting area of cutting edges and pile-up ratio, are used to quantitatively describe the material removal behavior. The experimental results show that the grits have good cutting performance. And the cutting edges involved in grinding change dynamically, which has a significant influence on material removal. In addition, this paper analyzes the differences between RABG and wheel grinding (WG), studies the effect of cutting depth on material removal, and determines the factors that affect the material removal ability by evaluating the material removal ability of different grits. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The known studies of heat treatment of copper slag are mainly directed to the recovery of metals from copper slag at the melting temperature. The conditions of increasing the strength of copper slag grains as a result of transition from amorphous to crystalline state during heating have not been studied. That is why the paper presents studies of microhardness and cutting properties of copper slag particles after heat treatment. Treatment regimens were assigned after calorimetric measurements of phase transition from amorphous to crystalline state of copper slag grains under isothermal conditions. It was found that for copper slag grains, crystallization proceeds in two stages. The first crystallization stage started at 762.6 °C (1035.75 K) and the second one at 795.1 °C (1068.25 K). Metallographic examination of microslides of copper slag grains after heat treatment at 800 °C showed that the HV microhardness value increased 1.5 times. It was found that the use of heat-treated copper slag grains for water jet cutting resulted in an accurate cut and smooth surface compared to the original abrasive. It has been revealed that heat treatment of amorphous copper slag contributed to the appearance of crystallites of sillimanite, pyrope, hematite, and zinc ferrite. [ABSTRACT FROM AUTHOR]

These days, metal matrix composites (MMCs) are being widely utilized in automotive and aerospace industries as prominent alternatives to traditional materials. Owing to their elevated strength-to-weight proportion, exceptional fracture toughness, and lightweight design, they can be used in a variety of applications. MMCs undergo extensive machining while making parts and components out of them. The machining of monolithic materials, such as metals and alloys, is a widely used and established process in different industries, such as the aerospace, bio-medical, and automotive sectors. Because of the properties of the metal matrix and the strong reinforcement, MMCs provide unique challenges. Modern machining processes have been found to be superior in overcoming challenges and achieving improved machinability of MMCs. An overview of MMC machining with modern methods is provided in this article. This article first outlines MMCs and addresses the need for and difficulties associated with their machining. Next, it reviews previous investigations on the machining of MMCs employing modern methods like electrical discharge machining, laser machining, abrasive machining, and hybrid machining. Productivity and surface integrity issues, including delamination and roughness, etc., are discussed. When presenting the review, the benefits and drawbacks of modern processes are also taken into account.

Super-reduced phases (SRPs), such as silicon carbide (SiC) and metal silicides, have increasingly been reported in various geological environments. However, their origin remains controversial. SRP inclusions (e.g., metal silicides and metallic silicon (Si0)) within SiC are commonly believed to indicate a natural origin. Here, we identified an unusual SRP assemblage (SiC, (Fe,Ni)Si2, and Si0) in situ in an H5-type Jingshan ordinary chondrite. Simultaneously, our analysis showed that the SiC abrasives contain (Fe,Ni)Si2 and Si0 inclusions. Other inclusions in the artificial SiC were similar to those in natural SiC (moissanite) reported in reference data, including diverse metal silicides (e.g., FeSi, FeSi2, Fe3Si7, and Fe5Si3), as well as a light rare earth element-enriched SiO phase and Fe-Mn-Cr alloys. These inclusions were produced by the in situ reduction of silica and the interaction between Si-containing coke and hot metals during the synthesis of the SiC abrasives. The results demonstrate that the SRP assemblage in the Jingshan chondrite originates from abrasive contamination and that the SRP inclusions (with a low content of Ca, Al, Ti, and Zr) cannot be used as a conclusive indicator for natural SiC. Additionally, the morphologies, biaxiality, and polytypes (determined by Raman spectroscopy) of SiC abrasives bear resemblance to those reported for natural SiC, and caution must be exercised when identifying the origin of SRP in samples processed by conventional methods using SiC abrasives. At the end of this paper, we propose more direct and reliable methods for distinguishing between natural and synthetic SiC.

In order to obtain automobiles that comply with the increasingly severe pollution standards, as well as to obtain some of them at low costs, a technical-economic approach to the flow of the fuel fluid through the flow holes of the injection nozzles is necessary. Through the effect of hydropolishing the geometric characteristics of the hydraulic flow path, the flow path is modeled, reducing cavitation and achieving high performance. The fluid used is a fluid that has properties close to diesel and has SiC microparticles in suspension (manufacturing costs in in this case they are reduced). The article contains an analysis of the influence of the abrasive flow on the geometric parameters of the nozzle and implicitly on the operation of thermal engines. The results provide a means of identifying parameters that can be compared and evaluated in order to achieve the desired level of hydrodynamic efficiency.

The microstructure of deposited layers with a composite material (CM) based on the self-fluxing PG-10N-01 alloy, modified with a mechanoactivated CM obtained using the self-propagating hightemperature synthesis, was studied. The X-ray phase analysis revealed in the deposited layer structure the inclusions of nickel borides NiB , Ni2B , Ni3B , chromium borides CrB , Cr2B , chromium carbides Cr3C2 , Cr7C3 , distributed in the nickel matrix. The modifying CM during arc welding contributed to the grinding of structure and reduction of the friction coefficient, increase of the microhardness of the deposited coatings, and decrease of the wear intensity in various friction conditions. [ABSTRACT FROM AUTHOR]

Efficiency and precision are two key indicators in the magnetic abrasive finishing (MAF) process. This paper presents the design of a core-shell structured magnetic abrasive particles (MAPs) with enhanced magnetic saturation rate and improved morphology. In addition, a processing roughness model based on indentation theory was developed by determining the number of active abrasive particles within the MAPs. The evolution of the MAF mechanism during the elastic and plastic deformation of processing material is clarified to realise high MAF efficiency and precision on slender tube surfaces. The grooves that slot on magnetic poles drive the maximum magnetic force on the MAPs. The simulation results from both the theoretical model of magnetic force and the active abrasive particle number theory are consistent with the actual experimental parameters, which effectively predict and explain the MAF phenomenon and mechanism. As to the zirconium alloy tube, the maximum improvement of five MAF passes on surface roughness Ra using the designed MAP is 63.38%, with the roughness Ra reaching 0.119 μm. [ABSTRACT FROM AUTHOR]

The microstructure of deposited layers with a composite material (CM) based on the self-fluxing PG-10N-01 alloy, modified with a mechanoactivated CM obtained using the self-propagating hightemperature synthesis, was studied. The X-ray phase analysis revealed in the deposited layer structure the inclusions of nickel borides NiB , Ni2B , Ni3B , chromium borides CrB , Cr2B , chromium carbides Cr3C2 , Cr7C3 , distributed in the nickel matrix. The modifying CM during arc welding contributed to the grinding of structure and reduction of the friction coefficient, increase of the microhardness of the deposited coatings, and decrease of the wear intensity in various friction conditions. [ABSTRACT FROM AUTHOR]

This study aimed to comprehensively analyze particulate matter (PM) emissions from vehicles, focusing on their sources based on combustion and non-combustion process, classification (PM10, PM2.5, PM0.1), and health implications (including PM transportation into lung). Employing bibliometric analysis, we assessed the growth of scientific publications related to PM, identifying top-cited works based on citations, publisher, author, country, and affiliation. We also visually mapped the development of research in this field using keyword-based publication data from Scopus (2019-2023) with the keywords "particulate matter", "emission", and "particle size" by utilizing Publish or Perish and VOSviewer software. Our findings underscore a significant uptrend in particulate matter research, shedding light on key areas of investigation. This study serves as a valuable resource for academics seeking research direction and a reference point for future investigations. [ABSTRACT FROM AUTHOR]

Copyright of Early China is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abrasive waterjet (AWJ) can be used to realize holes of any size and shape in difficult-to-machine ductile materials with negligible heat-affected zone by simply changing the jet path. In this study, the influence of various process parameters, such as waterjet pressure (P), jet traverse speed ( ν f ), abrasive mass flow rate (ma) on the AWJ-trepanned hole's geometrical features (diameter, taper angle, profile), form characteristics (circularity error, cylindricity error), quality measures (damage region, edge radius, burr formation, uncut material, surface morphology), and material removal mechanism in Al-6061 alloy is studied. The results show that higher P and ma at lower ν f are desirable for achieving nominal geometrical features, minimal form error, burr length, and uncut material. Damage region reduces with the decrease in P and ma at higher ν f . Edge radius reduces with the increase in P at lower ν f and ma. The micrographs showed that the initial damage region is uniform at higher P and lower ν f . Better surface quality is obtained at higher P and ma as lip formation and material pile-up are minimum. Material fracture and cracks in the vicinity of the burr are observed. Based on the mean response analysis, near-optimal parameters are suggested for efficient trepanning. [ABSTRACT FROM AUTHOR]

This study aimed to comprehensively analyze particulate matter (PM) emissions from vehicles, focusing on their sources based on combustion and non-combustion process, classification (PM10, PM2.5, PM0.1), and health implications (including PM transportation into lungs). Employing bibliometric analysis, we assessed the growth of scientific publications related to PM, identifying top-cited works based on citations, publisher, author, country, and affiliation. We also visually mapped the development of research in this field using keyword-based publication data from Scopus (2019-2023) with the keywords "particulate matter", "emission”, and "particle size" by utilizing Publish or Perish and VOSviewer software. Our findings underscore a significant uptrend in particulate matter research, shedding light on key areas of investigation. This study serves as a valuable resource for academics seeking research direction and a reference point for future investigations.

In order to improve the surface quality of tantalum wafer after chemical mechanical polishing (CMP), the effects of the particle size of nano-silica sol, type and mass fraction of chelating agent (i.e. glycine and disodium ethylenediaminetetraacetate), and mass fraction of oxidant (hydrogen peroxide) on the electrochemical behavior and removal rate of tantalum wafer, and its surface quality after polishing were studied by electrochemical testing and CMP experiments. The results showed that the removal rate of tantalum wafer was 71 nm/min when being polished in a slurry comprising 40% of nanosilica sol with an average particle size of 50 nm as abrasive, 1.0% of disodium ethylenediaminetetraacetate as chelating agent, and 1.0% of hydrogen peroxide as oxidant. The surface of polished tantalum wafer was free of orange peel and scratch. [ABSTRACT FROM AUTHOR]

In the present study, an advanced variant of abrasive flow machining (AFM) is developed. Ultrasonic assistance and magnetic field assistance with rotating effect have been designed, fabricated, and simultaneously used to develop ultrasonic-assisted magnetic abrasive flow machining (UAMAFM) process. The ultrasonic horn and electromagnets were designed based on the simu modified by adding iron particles to make abrasive media respond effectively under the applied magnetic field. The effects of the external assistances, machine, and media-based parameters were explored on the amount of material removed (MR) and percentage improvement in the surface roughness (% ΔRa) for pure titanium (Grade II). The influence of input parameters was investigated using analysis of variance (ANOVA) by analyzing the process responses. Quadratic regression models showing the effect of input parameters and their interaction were developed for each response. The influence of individual parameters on process outcomes and response surface plots for significant interactions have also been discussed. The maximum MR of 26.62 mg and ΔRa of 54.42% were achieved at the optimized setting of process parameters. The predicted values of MR and % ΔRa from developed statistical models agreed with the experimental results. [ABSTRACT FROM AUTHOR]

The reasons for the destruction of parts of the friction units of aircraft and ground aviation equipment, which are made of iron-based alloys, were analyzed, and it was established that during operation, various processes develop on their working surfaces, namely: abrasive wear, seizure, fretting - corrosion, fatigue wear. The analysis of modern technological methods of surface strengthening of machine parts was carried out, the prospects of electrospark alloying of iron-based alloys were determined. Research on the wear resistance of coatings was carried out using a complex methodology, which includes metallographic, electron microscopic, durometric, and other methods of analysis of physical and mechanical methods. The influence of electrode materials on the wear resistance of ESD coatings has been established. Practical recommendations for surface strengthening of parts of automatic transmission systems operating under conditions of abrasive wear are indicated. [ABSTRACT FROM AUTHOR]

Hard and brittle materials have excellent physical and mechanical performance, which are widely applied in the fields of microelectronics and optoelectronics. However, deep-hole machining of hard and brittle materials is very difficult and inefficient due to the high hardness and brittleness of these materials. To improve the quality and efficiency of deep-hole machining of hard and brittle materials, according to the brittle crack fracture removal mechanism of hard and brittle materials and the cutting model of the trepanning cutter, an analytical cutting force prediction model of hard and brittle materials processed using a trepanning cutter is established. This experimental study of K9 optical glass machining shows that as the feeding rate increase, the cutting force increase, and as the spindle speed increase, the cutting force decrease. By comparing and verifying the theoretical and experimental values, the average errors of axial force and torque are 5.0% and 6.7%, respectively, and the maximum error is 14.9%. This paper analyzes the reasons for the errors. The results indicate that the cutting force theoretical model can be used to predict the axial force and torque of machining hard and brittle materials under the same conditions, which provides a theory for optimizing machining process parameters. [ABSTRACT FROM AUTHOR]

Surface finishing operation is a very vital aspect of the manufacturing process and would not fully be achieved without abrasives such as emery paper. Some materials used in the production of abrasives like alumina (Al2O3), and Boron Carbide (B4C) are expensive thereby limiting their usage. This work is aimed at producing abrasive materials from snail shells, silica (SiO2), and epoxy resin while melamine formaldehyde acts as a hardener. The raw materials used were sieved according to ASTM E11-20 standard to obtain an average particle size of 400 µm. The composites were produced by varying different amounts of the epoxy resin as well as the other materials. The samples were analysed using physical, mechanical, and microstructural characterization techniques. An analysis of the results showed that as the content of the epoxy resin in the composite increased, the hardness values increased. The wear rate of the samples containing snail shell powders are higher than those containing only silica. The morphology of the samples obtained through microstructural tests revealed that the silica-based abrasive has better interfacial bonding which helped to confer strength. Therefore, silica can be used to produce abrasives with the required mechanical properties comparable to those of conventional abrasives.

ABSTRACT: Aim: The objective of this research was to determine the abrasive and remineralising efficacy of quail eggshell (Coturnix coturnix) incorporated into a new experimental toothpaste. Methods: An experimental study was designed to compare the surface microhardness of the dental enamel of bovine lateral incisors exposed to different toothpastes. In relation to microroughness (abrasive efficiency), the unit of analysis was each specimen with 16 polymethylmethacrylate (PMMA) blocks. For the remineralisation variable, the unit of analysis was each bovine lateral incisor tooth. A sample size of 16 was determined for each group. Results: The unpolished PMMA specimens presented the highest mean surface microroughness with a mean of 4.60 ± 1.47 µm, whilst the quail paste, universal polishing paste, control paste, and Diamond Excel Paste showed a mean of 1.16 ± 0.40 µm, 0.63 ± 024 µm, 0.45 ± 0.22 µm, and 0.43 ± 0.17 µm, respectively, presenting significant differences (P < .001). When comparing the surface microhardness of bovine lateral incisor dental enamel exposed to different toothpastes, the universal polishing paste presented the lowest microhardness, with 192.43 ± 56.21 kg/mm2, whilst the quail paste presented the greatest remineralising effect, with the highest average of 272 ± 21.18 kg/mm2, followed by the control paste with 244 ± 41.43 kg/mm2 and the Diamond Excel Paste with 228.72 ± 43.72 kg/mm2. These differences were statistically significant (P < .001). Conclusions: Significant differences were found in the surface abrasive efficiency (microroughness) of PMMA subjected to different toothpastes. The quail toothpaste presented statistically significant results compared to the control pastes, the Diamond Excel Paste, and the universal polishing paste.

This paper aims to assess the potential for the use of waste cellulosic fibers and recycled grains as materials for the development of abrasives. However, abrasive wear produces low durability and a lot of waste. The improvement of adhesion between the components of composites is the key to extending their lifetime. For this purpose, the surface of the fiber was modified by cationic reactive agents. Composites were manufactured with treated fibers, polyurethane matrix, and iron shavings as abrasive grains. To obtain this product, the coating phenomenon is maintained. DSC and TGA analysis show the thermal stability of abrasives. Contact angle and zeta potential measurements have been used to evaluate the specific surface-chemical changes imparted by surface treatments of specimens. EDX and SEM observations indicate that matrix-reinforcing particle-phase boundaries have a very important effect on the using properties of these materials and revealed that the abrasion resistance of composite is sensitive to fiber/matrix adhesion.

Surface modification of metallic alloys can create hydrophilic or hydrophobic surfaces that enhance the functional performance of the material. For example, hydrophilic surfaces have improved wettability, which improves mechanical anchorage in adhesive bonding operations. This wettability is directly related to the type of texture created on the surface and the roughness obtained after the surface modification process. This paper presents the use of abrasive water jetting as an optimal technology for the surface modification of metal alloys. A correct combination of high traverse speeds at low hydraulic pressures minimises the power of the water jet and allows for the removal of small layers of material. The erosive nature of the material removal mechanism creates a high surface roughness, which increases its surface activation. In this way, the influence of texturing with and without abrasive has been evaluated, reaching combinations where the absence of abrasive particles can produce surfaces of interest. In the results obtained, the influence of the most relevant texturing parameters between hydraulic pressure, traverse speed, abrasive flow and spacing has been determined. This has allowed a relationship to be established between these variables and surface quality in terms of Sa, Sz and Sk, as well as wettability. [ABSTRACT FROM AUTHOR]

Belt grinding is increasingly being used to process complex parts because of its ability to achieve flexible, form-following machining. Although the choice between down-grinding or up-grinding is one of the most common issues in process decisions, the influences of the differences in material removal mechanisms remain unclear, especially on surface residual stresses (RS). Thus, this paper focuses on the different grinding direction's influence on residual stress distribution, followed by a causal analysis of the abrasive cutting mechanism. The results suggest that the up-grinding surface is more prone to compressive RS of σa due to the different material flow directions close to the machined surface, and has stronger stress amplitudes of σt due to the increased belt wear caused by the grits entering from the hardened machined surfaces. For both down- and up-grinding, σa along the grinding trace's cross-section is symmetrically distributed in a peaked pattern, but σt is closer to a uniform distribution. One possible reason is that the contact wheel dissipates heat more quickly on both sides than in the center. Besides, the consistency of the RS distribution is better for up-grinding both within the same grinding trace and among different grinding traces. [ABSTRACT FROM AUTHOR]

Titanium alloys have been widely used in ships, aviation, aerospace, and other industries because of their excellent material properties. In the abrasive belt grinding of titanium alloy materials, abrasive belt grinding is a kind of flexible grinding, and its cutting force and material removal are important parameters that characterize the machining process. Powerful belt grinding can realize the removal of large materials, but ensuring its surface integrity is also crucial to the comprehensive material properties of titanium alloy materials. This paper studies the grinding amount: the effect of feed rate, linear speed, and initial grinding pressure on the grinding force, and the influence of the grinding force on the law of material removal and surface integrity. By studying the relevant parameters of abrasive belt grinding consumption, revealing its changing law, determining the best grinding range, and obtaining the best powerful grinding parameters. It is concluded that the maximum grinding force can be achieved when the maximum initial grinding pressure is 12N and the smaller feed speed is 200 mm/min and the medium-high line speed is 15.6 m/s while achieving a large margin of material removal and ensuring better surface integrity. [ABSTRACT FROM AUTHOR]