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Malachite green (MG), a cationic dye, is evaluated for removal using carboxylated activated carbon that was made using an organochlorine chemical and sodium hydroxide in a wet milling process (MCGT-AC). Utilizing research in Brunauer-Emmett-Teller (BET), X-ray diffraction, environmental scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fouriertransform infrared spectroscopy, and high-resolution transmission electron microscopy, adsorption processes were described. As per zeta potential and point of zero charge analysis a suitable and stable pH of 6.5 was considered for the modelled dye solution with increasing pH supporting the sorption process well. It just took 30 min for the MG dye to reach equilibrium with the MCGT-AC. The experimental findings agree well with the Langmuir isotherm, which has a maximum adsorption capacity of 251.6 mg/g, according to isotherm study and error analysis. The activation energy (Ea = 51.36 kJ/mol) indicated that chemisorption was responsible for controlling the process. BET study showed that the sorbent's post-process pore size dramatically decreased, supporting effective adsorption. Overall, adding functional groups (carboxyl, hydroxyl, etc.) to the modified adsorbent surface improved the sorption capacity of MCGT-AC with activated carbon that had been surface modified with carboxylic groups. The initial dye concentration, adsorbent dose, contact time, pH, and other operational parameters were examined. Regeneration research on utilized MCGT-AC revealed that during the sixth cycle, adsorption capacity dropped from 95.7% to 48.6%. According to the results, MCGT-AC may be used as a cost-effective and effective adsorbent for the treatment of industrial wastewater, including dyes. [ABSTRACT FROM AUTHOR]

Disposal of Used Foundry Green Sand (UFGS) remains one of the significant challenges faced by foundry industry nowadays. Experiments were performed to reduce the total clay content from 12% to as low as 2.2% in waste foundry sand. Three prototypes were developed during the course of this work. They include vertical fluidized bed, horizontal fluidized bed and a novel ball-mill type attrition and sieving unit. The cost per ton of reclaimed sand is higher in case of fluidized bed based prototypes while in case of attrition and sieving based prototype, it is less than half of the cost of the fresh sand. The experimental data generated on the two-stage attrition and sieving unit under different conditions is further used to arrive at a semi-empirical correlation and the optimum set of design and operating parameters to get the best performance. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate that a new mechanical attrition process can be used to prepare nanosilicon powder from metallurgical grade silicon lumps. Composite Li-ion anode made from this nanometer-size powder was found to have a high reversible capacity of 2400 mAh g −1 and an improved cycling stability compared to micrometer-sized powder. It is proposed that improved battery cycling performance is ascribed to the nanoscale silicon particles which supresses the volume expansion owing to its superplasticity. [ABSTRACT FROM AUTHOR]

Controlled shot-peening/blasting is an operation which is used largely in the manufacturing industry. An attempt is made to create a case-hardened surface by the shot peening technique on a Ni-Cr-Mo steel. Steel shots with activated carbon powders were introduced at the surface of the samples for different periods of time, i.e. for 5, 10, 15 and 20 min. The microstructure, chemical composition, and hardness were investigated by optical microscopy, SEM, OES, XRF, XRD and micro-Vickers hardness tester, respectively. An effective diffusion of carbon atoms was found in the samples subjected to shot peening for 10 min. and above. However, the hardness values were found to be non-uniform and showed a maximum hardness of 300 HV at activated spots. The microstructural studies revealed formation lamellar-shaped cells consisting of nano grains at the shot peened surface. A close observation of these lamellae shows α-ferrite and cementite (FeC) formed by diffusion of carbon into iron at room temperature. XRD results confirmed the formation of CrC and FeC by shot peening with activated carbon. [ABSTRACT FROM AUTHOR]

• Effects of mechanical attrition on REE minerals was revealed by MLA. • At −38 µm fraction, the distribution of REEs increased to 70 %. • Liberation of REE minerals determined as 50% averagely. • New REE minerals were determined and presented for Eskisehir-Beylikova ore. Eskişehir-Beylikova ore has one of the high-potential rare earth element (REE) reserves worldwide. In addition to recovering of REEs from these ores, industrial-scale enrichment of barite, fluorite and thorium continues intensively. However, there have been problems with beneficiation due to the particle size liberation. The most significant point for selecting beneficiation method in a cost-effective way depends on the characterization studies that reveal the mineralogy, mineral associations, and liberation size. According to the recent studies that focused on the beneficiation of Eskişehir ore, it was pointed out that REEs accumulated – 5 µm and before beneficiation of those minerals mechanical attrition was needed. However, the effects of mechanical attrition and how it affects behaviors of the rare earth in the fine fractions have not explained clearly. Therefore, this research has focused on filling this gap in the literature to reveal the effects of mechanical attrition on the beneficiation of rare earth elements using the MLA technique. Regarding results, after the mechanical attrition process, the amount of −38 µm increased by 20 % in the scrubbed sample, and the distribution of REEs enhanced from 15 % to 70 %. The liberation degree of REEs enhanced by 10–25 %, and mineral associations decreased at – 38 µm. From EDS results, Rare earth carbonate, Th-Parisite, Synchysite, Carbocernaite, and Monazite were determined as the rare earth minerals. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, the sliding wear behaviour of surface mechanical attrition (SMA) treated AISI 304 stainless steel by spherical shot peening has been studied under both unlubricated and lubricated conditions under various contact loads. It was found that although SMA treatments could produce a hardened layer of several hundred microns thick with much increased hardness from 200 HV0.1 to 480 HV0.1, SMA treatments did not have a significant effect on the unlubricated wear behaviour of the steel. However, under oil-lubricating conditions, the SMA treated steel showed much better wear resistance than the untreated steel over a wide range of contact loads. The results are discussed in terms of plastic deformation and property changes induced during the sliding wear process. [Copyright &y& Elsevier]

Surface nanocrystallization by mechanical attrition was used to enhance the chemical vapor deposition process. An aluminum (Al) diffusion coating was produced on AZ91 Mg alloy surface. This process was conducted at a relatively low temperature (400°C) for a short time of 120 min. The results indicated that a continuous and dense Mg17Al12 intermetallic coating with a thickness of ∼8 μm formed on the Mg alloy substrate. Almost no corrosion was observed after the coated samples were immersed in 3 wt % NaCl solution for 6 h, reflecting a relatively good corrosion resistance. The formation mechanism of the Al diffusion coating is discussed based on the experimental results. [ABSTRACT FROM AUTHOR]

Abstract: AISI 316 austenitic stainless steel samples were plasma nitrided in variable process times at low temperature (300°C). Two different pretreatments were performed where ball milling (mechanical attrition) and argon plasma (atomic attrition) were used in order to study their posterior effects on plasma nitriding. X-ray diffraction, scanning electron microscopy and nano-indentation experiments were performed for characterization before and after plasma nitriding. Mechanical attrition produces a phase transformation of the original crystalline structure while atomic attrition creates preferential planes in the same crystalline structure. After plasma nitriding and although both pretreatments increase the hardness, the atomic attrition shows the highest hardness values. The mechanical attrition decreases the nitrided layer thickness due to surface oxidation that creates a potential barrier for nitrogen incorporation. [Copyright &y& Elsevier]

Abstract: Samples of Sn30TM30C40 and of Sn30Co15TM15C40, with TM=3d transition metals, were prepared by vertical-axis attritor milling. The structure and performance of these samples were studied by X-ray diffraction (XRD) and by electrochemical testing. The XRD patterns of Sn30TM30C40 show an amorphous-like diffraction pattern only for the sample with TM=Co. The other prepared samples show broadened Bragg peaks of their main starting material, along with an amorphous-like background, even after 32h of milling. Samples with TM=Co and TM=Ni show stable differential capacity versus potential plots and stable cycling for at least 100 cycles with reversible capacities of 425 and 250mAhg−1, respectively. All samples prepared with 15at.% Co show good capacity retention for at least 100 cycles ranging from 270mAhg−1 for samples with TM=Ni to 500mAhg−1 for samples with TM=Ti. The differential capacity versus potential plots for all the prepared Sn30Co15TM15C40 samples show similar structure to that of Sn30Co30C40 except when TM=Cu. This shows the possibility of preparing tin-based negative electrode materials using a combination of cobalt and TM, especially if one looks to reduce the cobalt content. [Copyright &y& Elsevier]

Abstract: High-energy ball milled nanocrystalline TiO2 (anatase) was analyzed by means of electrochemical impedance spectroscopy in a temperature range from 473K to 873K and under reducing and oxidizing atmospheres. The electrical properties are compared with the photocatalytic activity of the samples. [Copyright &y& Elsevier]

Abstract: Using a vertical-axis attritor, samples of (Sn x Co1−x )60C40 for 0≤ x ≤0.7 have been prepared in increments of Δx =0.1. The effect of Sn content on the structure and performance of the Sn–Co–C nanocomposites was examined by X-ray diffraction (XRD), 119Sn Mössbauer effect spectroscopy and electrochemical methods. XRD shows a diffraction pattern characteristic of a nanostructured material having amorphous CoSn grains in a carbon matrix for x =0.5. Broad Bragg peaks of Co3C, SnCo3C0.7 and CoSn2 were observed for samples with 0≤ x ≤0.1, 0.1≤ x ≤0.4 and 0.5< x ≤0.7, respectively. 119Sn Mössbauer effect spectroscopy shows the presence of an amorphous CoSn component in samples with 0.3≤ x ≤0.6. Samples with a large amount of the SnCo3C0.7 phase showed small capacity for lithium. Therefore, SnCo3C0.7 is best described as an inactive phase. The sample with x =0.7 shows the highest specific capacity (about 600mAh/g) of all samples prepared but exhibited poor capacity retention after cycle 45. Excellent charge–discharge capacity retention, reasonable specific capacity (>450mAh/g) along with stable differential capacities were observed for samples near x =0.5. [Copyright &y& Elsevier]

Abstract: Nanoparticles comprising of magnetite (Fe3O4) core–hematite (α-Fe2O3) shell with mean diameter around 9nm were synthesized by mechanical grinding. Zero-field-cooled (ZFC) and field-cooled (FC) magnetization and hysteresis loop measurements were carried out over the temperature range 5–300K. Exchange bias varying from 140 to 10Oe was observed. This is explained as arising due to ferrimagnetic–antiferromagnetic coupling at the nanointerfaces between the two phases. Analysis of data shows a pronounced increase in the effective anisotropy constant as the milling time is increased. [Copyright &y& Elsevier]

Abstract: Mechanical milling/attrition provides a convenient scope of simulating the microstructural changes encountered by wear-resistant coating alloys subjected to deformation under high frequency and high-intensity impact loading or accelerated wear condition. In the present study, the microstructural evolution of two commercial coating materials, FeCrB (Armacor M) and FeCrNiCoB (Armacor C), in the course of low- and high-intensity mechanical attrition, was monitored by X-ray diffraction and high-resolution transmission electron microscopy. While low-intensity milling leads to marginal grain refinement but no change in phase-aggregate in FeCrB, similar mechanical attrition causes boride precipitation in FeCrNiCoB alloy powder. On the other hand, attrition in high-intensity mill leads to formation of a nanocrystalline extended solid solution of ferrite in FeCrB and nanocrystalline two-phase mixture of boride and austenite in FeCrNiCoB, respectively. Furthermore, continued milling seems to produce partial solid-state amorphization, particularly in FeCrB. On isothermal heating, the milled powders (both FeCrB and FeCrNiCoB) develop identical two-phase nanocrystalline aggregate signifying large-scale solute redistribution and nearly the same level of metastability of the deformed microstructure. Thus, it is concluded that the microstructure and hence wear resistance of FeCrB and FeCrNiCoB coatings is likely to undergo significant changes during high load and high strain rate impact or wear condition. [Copyright &y& Elsevier]

Mechanical attrition has been applied to improve the electroless plating process on a magnesium alloy. The results indicated that an alloyed layer forms at the interface of Ni–P coating and magnesium alloy. The Ni–P coating becomes smooth, compact, has refined grains and is free of cracks and pores. The phase of the Ni–P coating transformed from amorphous to crystalline. Consequently, the coating adhesion, hardness and corrosion resistance have been improved significantly. [Copyright &y& Elsevier]

Abstract: Ni coating was deposited on carbon steel by a mechanical attrition enhanced electroplating (MAEE) process. The electroplating was conducted in a traditional Watts'' solution and the mechanical attrition action was applied by impact of glass balls on the sample surface with a special vibrating frequency. It is shown that the attrition has significant effects on the microstructure and the characteristics of electroplated Ni coating. When the current density is below a limited current density (i L), the growth of grains is hindered under the mechanical attrition action and the nucleation of Ni grains processes at a high rate. Thus the Ni coating deposited has smooth surface morphology, refined grain size, pore-free, and with increased microhardness and excellent corrosion resistance. When the current density is above i L, Ni dendrites formed by conventional electroplating can be cold-welded together by the moving glass balls, resulting in a compact Ni coating. Therefore, high-dense Ni coatings can be plated at a high current density and deposition rate. [Copyright &y& Elsevier]

Abstract: High energy ball milling, vertical-axis attritor milling and co-sputtering were used to prepare Sn30Co30C40 or Sn36Co41C23 electrode materials. By varying the milling conditions, it was possible to obtain nanostructured materials by mechanical methods whose X-ray diffraction patterns mimicked the diffraction pattern of the co-sputtered material. Electrochemical testing showed that composite electrodes made from each of the prepared materials showed stable charge–discharge capacity for at least 100 charge–discharge cycles and stable differential capacity versus potential profiles. Although the materials appear to be similarly nanostructured, the sputtered material showed a reversible capacity near 610mAh/g, close to the theoretical capacity of 661mAh/g, while the best material prepared by mechanical methods attained a specific capacity near 470mAh/g. Further experiments are required to understand the differences in the nanostructure of these materials that leads to the differences in attained specific capacity. [Copyright &y& Elsevier]

Experimental data of ash-particles attrition in a fluidized bed is presented, and also the results of modeling. Five sizes of ash particles ( 1.02-:-1.25; 1.25-:-1.6; 1.6-:-2.0; 2.0-:-5.0; 5.0-:-10.0 mm) produced in an industrial CFB boiler were examined. A new model of mechanical attrition has been proposed which incorporates new parameters: the shape factor of particles and the ratio of the bed height to bed diameter, strongly influencing the rate of bed mass loss. The model describes very well experimental data for coal-ash particles attrition. The attrition-rate coefficient for ash particles was evaluated. [ABSTRACT FROM AUTHOR]

In terms of the grain refinement mechanism induced by plastic straining, a novel surface mechanical attrition treatment (SMAT) was developed for synthesizing a nanostructured surface layer on metallic materials in order to upgrade the overall properties and performance. In this paper, the SMAT technique and the microstructure of the SMAT surface layer will be described. The grain refinement mechanism of the surface layer during the SMAT will be analyzed in terms of the microstructure observations in several typical materials. Obvious enhancements in mechanical properties and tribological properties of the nanostructured surface layer in different materials were observed. Further development and prospects will be addressed with respect to the SMAT as well as the performance and technological applications of the engineering materials with the nanostructured surface layer. [Copyright &y& Elsevier]

Extreme plastic deformation encountered in a variety of mechanical processes may yield nanostructured and nanophase materials with a broad range of chemical composition and microstructure. This paper discusses several such examples including the deformation induced nanophase formation in powder particles, thin foil sandwich structures, and at the surface of metals and alloys exposed to friction induced wear conditions. The deformation processes occurring within powder samples during mechanical attrition are important for fundamental studies on the effect of extreme mechanical deformation on the microstructure and its stability. [ABSTRACT FROM AUTHOR]

A jet attrition model is developed to predict the evolution of the particle size distribution in fluidized beds. This model predicts changes in particle size distribution due to impact attrition in the jet region as a function of operating parameters – temperature, particle impact velocity and time. The model provides good agreement with experimental results for iron and hematite as oxygen carriers, with limestone and lime as CO 2 sorbent at temperatures from 20 to 800 °C and jet velocities from 59 to 221 m/s. It is found that fragmentation, abrasion, and material fatigue over the attrition duration must be considered. Two fitting parameters considering fatigue by material properties and repeated collisions are applied in this model, with their values determined based on nonlinear least squares regression following the evolution of the particle size distribution. Unlabelled Image • A jet attrition model is developed for single and binary solid species. • Particle impact velocity in the jet is fitted by an empirical equation. • Fragmentation and abrasion are considered in the jet attrition model. • Particle fatigue is considered to affect material properties over time. [ABSTRACT FROM AUTHOR]

Abstract: Cu–Zr–Ti powders were deposited onto Cu plates by thermal spray. Upon impact onto the substrate, the particles spread out and bond well to the substrate, yielding a well adhered surface layer. The coatings then were subjected to severe plastic deformation using surface mechanical attrition treatment in a high energy SPEX 8000 shaker mill by replacing the end cap of the milling vial with the coated targets. It is demonstrated that different mechanical treatments influence the microstructural and mechanical behavior of the Cu–Zr–Ti coating, moreover, a partial solid state amorphization takes place. Roughening of the interface between target and coating ensures strong bonding while the free surface is hard and smooth. Experiments were carried out using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and hardness measurements. [Copyright &y& Elsevier]