Abrasive Particle Size Research Articles

Environment-friendly, efficient process for mechanical recovery of waste lithium iron phosphate batteries.

Technology for recycling retired lithium batteries has become increasingly environment-friendly and efficient. In traditional recovery methods, pyrometallurgy or hydrometallurgy is often used as an auxiliary treatment method, which results in secondary pollution and increases the cost of harmless treatment. In this article, a new method for combined mechanical recycling of waste lithium iron phosphate (LFP) batteries is proposed to realize the classification and recycling of materials. Appearance inspections and performance tests were conducted on 1000 retired LFP batteries. After discharging and disassembling the defective batteries, the physical structure of the cathode binder was destroyed under ball-milling cycle stress, and the electrode material and metal foil were separated using ultrasonic cleaning technology. After treating the anode sheet with 100 W of ultrasonic power for 2 minutes, the anode material was completely stripped from the copper foil, and no cross-contamination between the copper foil and graphite was observed. After the cathode plate was ball-milled for 60 seconds with an abrasive particle size of 20 mm and then ultrasonically treated for 20 minutes with a power of 300 W, the stripping rate of the cathode material reached 99.0%, and the purities of the aluminium foil and LFP reached 100% and 98.1%, respectively.

Experimental Study on Shear Rheological Polishing of Si Surface of 4H-SiC Wafer

In this study, shear rheological polishing was used to polish the Si surface of six-inch 4H-SiC wafers to improve polishing efficiency. The surface roughness of the Si surface was the main evaluation index, and the material removal rate was the secondary evaluation index. An experiment was designed using the Taguchi method to analyze the effects of four critical parameters (abrasive particle size, abrasive particle concentration, polishing speed, and polishing pressure) on the Si surface polishing of SiC wafers. By evaluating the experimental results for the signal-to-noise ratio, the weight of each factor was calculated using the analysis of variance method. The optimal combination of the process parameters was obtained. Below are the weightings for the influence of each process on the polishing result. A higher value for the percentage means that the process has a greater influence on the polishing result. The wear particle size (85.98%) had the most significant influence on the surface roughness, followed by the polishing pressure (9.45%) and abrasive concentration (3.25%). The polishing speed had the least significant effect on the surface roughness (1.32%). Polishing was conducted under optimized process conditions of a 1.5 μm abrasive particle size, 3% abrasive particle concentration, 80 r/min polishing speed, and 20 kg polishing pressure. After polishing for 60 min, the surface roughness, Ra, decreased from 114.8 to 0.9 nm, with a change rate of 99.2%. After further polishing for 60 min, an ultrasmooth surface with an Ra of 0.5 nm and MRR of 20.83 nm/min was obtained. Machining the Si surface of 4H-SiC wafers under optimal polishing conditions can effectively remove scratches on the Si surface of 4H-SiC wafers and improve the surface quality.

Polarized laser scattering detection of subsurface damage of quartz glass induced by grinding

Subsurface damage (SSD) is inevitably generated during the grinding process of quartz glass. It has a great impact on sustainability, lifetime and optical performance of quartz glass components and systems. This paper proposes a non-destructive detection method for detecting SSD in ground quartz glass based on polarized laser scattering (PLS). A PLS system was built to detect SSD in ground quartz glass samples prepared with different abrasive particle sizes. The PLS detection signal value had a positive correlation with the SSD depth. The finite-difference time-domain (FDTD) method was used to simulate the laser scattering process at the SSD. The distribution of electric field intensity could reflect the location of SSD. It is concluded that the PLS system can effectively detect SSD in the ground quartz glass.

Influences of abrasive particles on tribological behaviours of rotary vane steering gear seals under oil

The wear particles often cause the abnormal wear processes to the rotary vane seals, which lead to seals failure and dropping hydraulic oil pressure, and eventually result in losing of the function of rotary vane steering gear. Clarifying the friction and wear mechanisms between the vane seals and the cylinders and extracting their key wear characteristics are the keys to extend the service life and realize intelligent fault diagnosis of the rotary vane steering gears. Different kinds of hydraulic oils mixed up with different sizes of iron particles were chosen to investigate the abrasive particles on the wear behaviours between the polyurethane polymer and carbon steel specimens. The wear characteristics such as coefficients of friction (COF), wear morphologies, frictional-induced vibration signals were examined and analyzed synthetically. The results showed that the coefficients of friction, wear morphologies, surface roughnesses and vibration signals increased as a function of the iron particle sizes, which indicated that the wear state was gradually worsening. The three-body friction and wear mechanisms were disclosed clearly. There was a certain mapping relationship between the wear characteristics and wear states, and sensing the tribological information between the rubbing pairs, including coefficient of friction, abrasive particle size in hydraulic oil, wear morphology, vibration signal and other characteristics, was a potential and effective way for evaluating or predicting the wear states or failure modes of rotary vane steering gear seals. This study provides a theoretical basis for revealing the friction and wear mechanisms of ship rotary vane steering gear seals, and is useful for accomplishing their intelligent monitoring and fault diagnosis.

Study on the Wear Modes of PVD Films Using Different Concentrations of Al2O3 Abrasive Particles and Textured Rotating Balls

Abrasive wear is a wear mechanism that results in a loss of material from the interaction of a surface with hard particles. This type of wear is frequently found in the surface of machining tools. Microscale abrasion equipment is often used to characterize the resistance to abrasive wear of a surface. The different parameters able to control micro-abrasion wear tests, such as ball rotation, sliding distance between ball and surface sample, abrasive slurry concentration, normal load acting on the sample, and abrasive flow rate over the sample, have been widely studied. The combination of different variables, including sliding distance, concentration of abrasive particles, their hardness, and size of abrasive particles, promotes the transition between two-body, three-body, or mixed abrasive wear modes. However, the influence of the ball surface on the dragging of abrasive particles, which is reflected in the wear modes, is still poorly studied. One of the variables possible to control and less studied is the influence of the ball surface texture on the dragging of abrasive particles in micro-abrasion wear tests. This work intends to correlate the effect of different testing times (500, 1000, and 1500 cycles) and different concentrations of 3 μm Al2O3 abrasive slurry (25, 35, and 45 g/100 mL) on the micro abrasion resistance of a TiN thin coating film, using balls of AISI 52100 steel whose texture and roughness were prepared by 60 s chemical etching. The rotation speed of each test was 80 rpm, applying a normal load of 2 N. Subsequently, the craters were carefully analyzed using SEM to evaluate the transition of the wear mode as a function of the applied load, the abrasive particle concentration, and the sliding distance. The textured ball tracks were observed via SEM to assess the particle dynamics. The results showed that, contrarily to what is reported in the literature regarding wear modes where rolling is promoted with increasing abrasive concentration, in this work grooving took place instead. This is a result of the rough balls use in the experiments which, due to the embedment of abrasive particles in the ball grooves, promotes the abrasion mechanism. The higher the abrasive concentration, the higher the grooving mechanism, since more particles are available to scratch the surface.

Research on Chemical Mechanical Polishing Technology for Zirconium-Based Amorphous Alloys

Crystallization often occurs in the processing of amorphous alloys, causing the materials lose their excellent properties. The study adopts chemical mechanical polishing of amorphous alloys, presenting the effect of the rotational speed of the polishing turntable, size of abrasive, polishing pressure, and oxidant concentration. The Taguchi method is used to find the best processing parameters, and AFM is used to characterize the machined material surface. At the same time, XPS is used to detect the change of oxide film composition with the addition of oxidant. The results indicate the optimum process parameters: rotational speed of the polishing turntable is 75 r/min, polishing pressure is 28.3 kPa, the size of abrasive is 0.5 μm, and the size of abrasive is a significant factor affecting surface roughness Sa. In addition, as the size of abrasive increases, the material removal rate increases while the surface roughness Sa increases. At pH 10, with an abrasive particle size of 0.5 μm, as the H2O2 concentration increases, the MRR first rapidly decreases at 0.21 wt.% H2O2, and then gradually increases, while the Sa decreases. Furthermore, with the addition of oxidant, the main composition of the surface oxide film changes from oxide to hydroxide, and the contents of Zr4+ and Cu0/Cu1+ elements increase. The findings can provide a feasible chemical mechanical polishing process for zirconium-based amorphous alloys to obtain a satisfactory polishing effect.

Material Removal Characteristics of Spherical-Array-Focused Ultrasonic Abrasive Machining.

To improve the ultrasonic energy and realize far-field ultrasonic abrasive machining of complex surfaces, a spherical-array-focused ultrasonic abrasive machining system was established. By combining ultrasonic field simulation, detection and a single-factor experiment, the influences of the ultrasonic generator current, abrasive concentration, and particle size on the material removal properties and surface quality evolution of quartz glass were investigated. When the current was less than 0.4 A, the material removal showed plastic removal at the nanoscale. When the current was more than 0.5 A, the cavitation phenomenon formed micron-scale impact removal traces on the workpiece surface. The increase in abrasive concentration increased the impact density and material removal rate, while excessive abrasive concentration increased the impeding effect between abrasive particles and reduced the material removal rate. Moreover, the increase in abrasive particle concentration enhanced heterogeneous cavitation nucleation, promoted the removal of abrasive impact materials under the action of a cavitation jet, and inhibited the removal of direct surface cavitation. The abrasive particle size affects the heterogeneous cavitation nucleation and the acceleration of the cavitation jet on abrasive particles, which affects the material removal rate and surface quality. By controlling the energy of the focused ultrasound and abrasive parameters, the plastic or brittle domain removal of quartz glass can be achieved at the micro- and nanoscales.

Three-Body Abrasive Wear-Resistance Characteristics of a 27Cr-Based 3V-3Mo-3W-3Co Multicomponent White Cast Iron with Different Ti Additions

A multicomponent white cast iron containing 5 wt.% each of Cr, V, Mo, W, and Co (MWCI) is known to have excellent wear-resistance properties due to the precipitation of some very hard carbides, such as MC, M2C, and M7C3. However, it seems possible to improve the wear resistance of MWCI by increasing the carbide volume fraction (CVF). Thus, 27 wt.% Cr based on 3 wt.% each of V, W, Mo, and Co was simultaneously added into the white cast iron. To avoid the tendency of carbides to crack due to high M7C3 precipitation levels, titanium (0–2 wt.% Ti) was also added. A rubber wheel abrasive machine test according to the ASTM G65 standard with two different abrasive particle sizes (average: 75 and 300 μm) was used to evaluate the wear characteristics of the alloy. The results show that the wear resistance of these new alloys (0Ti, 1Ti, and 2Ti) is lower than that of MWCI in small silica sand, owing to the lower hardness. However, a different condition is present in large silica sand, for which the abrasive wear resistance of MWCI is lower than that of the 0Ti and 1Ti specimens. In addition, TiC precipitation effectively refined the size of M7C3 carbides and reduced their cracking tendency. Thus, the wear resistance of 1Ti is comparable to that of 0Ti, although it has a lower hardness factor. However, the wear resistance of the alloy significantly decreased following the addition of Ti by more than 1 wt.% due to the lower hardness and CVF. Therefore, it can be said that the abrasive wear characteristics of the alloy are not only affected by the hardness, but also by the micro-structural constituents (type, size, and volume fraction of carbides) and silica sand size.

Surface integrity and material removal mechanism in fluid jet polishing of optical glass

Fluid jet polishing (FJP) is a promising technology that has been increasingly used in the superfinishing of complex optical lenses, mirrors, and molds on several materials. The influence mechanism of polishing parameters on the damage characteristics, element composition, and surface quality of optical glass was studied through a series of FJP experiments to achieve the high-efficiency and low-damage ultra-precision polishing requirements of optical components. A numerical model for FJP was developed based on computational fluid dynamics (CFD), and the effects of slurry pressure and particle size on the flow field and particle motion characteristics were studied combined with statistical theory. The brittle-ductile transition model and erosion model when abrasive particles eroded optical glass were established to obtain a better understanding of the material removal mechanism during FJP. The damage control strategy can be clarified according to the coupling relationship between the impact velocity and particle size of abrasive particles when radial and transverse cracks are generated in the optical glass. The experimental results verify that the established model can predict the material removal characteristics well. The simulation results also indicate that the erosion removal of the optical glass by abrasive particles is a completely ductile mode under the polishing experimental conditions in this study. The results can provide solid theoretical support for equipment upgrade and process optimization of FJP.

Simulation and Experiment Research on Abrasive Wear of the Ship Mechanical Seal

The wear of friction pair resulting from seawater particles will inevitably bring marine tail shaft mechanical seal in the process of work, and abrasive wear will increase the static ring wear, resulting in the leakage of the mechanical seal. In this paper, through finite element simulation analysis of abrasive wear with different particle sizes and abrasive wear tests under different static ring materials, it is concluded that larger abrasive particle sizes will increase the deformation and residual stress on the surface of static ring materials, thus increasing the amount of wear, and the surface of softer static ring materials will be more serious. Also, if the particle size is too large, the particle concentration of the friction surface will decrease, and the wear will decrease.

Preliminary DOE Analysis of the Polishing Process of AISI P20 Mould Steel by Ultrasonic Erosion, Using Alumina and Diamond Hard Particles

The present work examines the surface finishing of AISI P20 tool steel, average hardness of 31.5 HRc, in the polishing process by ultrasonic erosion by loose abrasive particles. The study was performed in laboratory equipment, using various alumina and diamond hard particle sizes, ultrasonic frequencies and times. P20 steel is widely employed in the fabrication of polymer injection mould cavities due to its good machinability, homogeneous microstructure, hardness, corrosion and abrasion wear resistance. Mould cavity polishing processes represents the second longest manufacturing process time required to achieve the mould surface finish for good quality polymer parts. This time-consuming and largely artisanal polishing process contributes to high mould costs. Thus, several studies have been carried out in the literature to automate the mould polishing process, aiming to reducing surface roughness and polishing time. Present investigation was carried out in a surface cleaning equipment by the ultrasonic technique with commercial paste of abrasive hard particles used in mould polishing. Three factors were investigated: abrasive particle size, ultrasonic frequency and polishing time. The investigated alumina particle sizes were 0.05, 0.3, and 1.0 micron and the diamond particle size was 1.5 micron, which are the common sizes available in commercial paste for polishing metallography samples. The studied frequencies of the ultrasonic polishing process were 28 and 40 kHz, and the times of polishing process were 15, 30, and 45 minutes. Analysis of variance (ANOVA) of factor effects and two types of DOE analysis were employed to obtain the roughness Ra outcomes by empirical response surface modelling: 3x3 partial factorial design and 4x2 factorial design were used to investigate the surface roughness. The response surface modelling results indicate that the minimum surface roughness Ra of 0.21 micron obtained by ultrasonic polishing correspond to the frequency of 40 kHz, 20 minutes of polishing and alumina particle size of 0.7 microns.

Preparation and Characterization of In Situ (TiC-TiB2)/Al-Cu-Mg-Si Composites with High Strength and Wear Resistance.

This study involved the preparation and characterization of in situ (TiC-TiB2)/Al-4.7Cu-0.32Mg-0.44Si composites with excellent mechanical and abrasive wear properties. The composites were synthesized in an Al-Ti-B4C system by combining combustion reaction synthesis with hot-pressed sintering and hot extrusion. The in situ TiB2 and TiC particles were of multi-scaled sizes ranging from 20 nm to 1.3 μm. The TiB2 and TiC particles effectively increased the yield strength (σ0.2), ultimate tensile strength (σUTS), hardness (HV), and abrasive wear resistance of the composites. The 40 wt.% (TiC-TiB2)/Al-4.7Cu-0.32Mg-0.44Si composite exhibited the highest σ0.2 (569 MPa), σUTS (704 MPa) and hardness (286 HV), which were 74%, 51% and 110% higher than those of the matrix alloy, respectively. Compared with the matrix alloy, the abrasive wear resistance of the 40 wt.% (TiC-TiB2)/Al-4.7Cu-0.32Mg-0.44Si composite was increased by 4.17 times under an applied load of 5 N and Al2O3 abrasive particle size of 13 µm. Micro-ploughing and micro-cutting were the main abrasive wear mechanisms for the Al-Cu-Mg-Si alloy and the composites.

Grinding and Polishing Repair Technology and Experimental Research on Surface Defects of Flywheel Disc Semi-Finished Products

The flywheel disc is an important engine component that is widely used in industries such as automobiles, ships, and flywheel energy storage. In this paper, single-factor experiment, and orthogonal experiment are used to explore the influence of abrasive particle size, grinding speed, grinding pressure, and grinding time on the surface roughness and material removal rate of flywheel disc semi-finished products (cold-rolled steel). The results show that the optimal combination of parameters for the surface defect repair process of flywheel disc semi-finished products is: abrasive particle size of W20, grinding speed of 40 r/min, grinding pressure of 3 psi, grinding time of 40 min, and an average surface roughness of 342nm. The repaired flywheel disc semi-finished product has great surface quality and meets the requirements of factory repair.

Research on abrasive pool machining method based on gas–solid two-phase flow

For complex curved difficult-to-machine parts, a new method based on pneumatic suspension abrasive pool bright finishing processing is proposed, using the mixing of pneumatic suspension abrasive, the workpiece surface, and fluidized abrasive to produce relative motion velocity, so that the solid particles and workpiece surface microscopic two-body abrasive wear to achieve the effect of precision machining. The experimental test material is the widely used Q235 steel plate. The experimental parameters include workpiece shape (round tube, square tube, cylindrical), abrasive particle size (24, 80, 120 mesh count), gas–solid two-phase flow pattern (dispersion fluidization state, turbulent fluidization state, spurting fluidization state), abrasive particle shape (sphere, irregular), and spindle speed (600, 900, 1200 rpm). An orthogonal test was designed according to the experimental parameters, and the degree of influence of each parameter on the processing of the abrasive cell was evaluated by the roughness of the workpiece surface together with the scanning electron microscope (SEM) micrograph of the workpiece surface, and the optimal combination of parameters was judged using the extreme difference method as well as the factor trend diagram. The results show that under the present experimental conditions, the workpiece surface roughness (Ra) can reach a minimum value of 0.4 μm. The feasibility of gas–solid two-phase flow processing is demonstrated from an experimental point of view, and the advantages of abrasive cell processing are explored.

To Investigate the Reduction in Kerf Taper Angle & Abrasive Waterjet lagging of Hard Ductile Inconel 625 with Abrasive Water Jet Machining with using Mathematical Model

Inconel 625 were studied to reduce in kerf taper angle by reducing water jet lagging with added polymer (PAM) to reduce the softening area when cutting the material on the abrasive waterjet cutting machine and to obtain a flat surface using the above listed materials. Used a combination of water pressure, abrasive particle size, nozzle size, polymer additive & Abrasives (Silica Sand) additive by percentage mass as process parameters & to check validation by mathematical model.

The Removal Mechanism Considering the Shape and Size of Abrasive Particles in Wet Blast Cleaning of Paint

Recently, wet blast cleaning of paint has attracted attention in remanufacturing processes, owing to its high efficiency and environmental friendliness. However, studies of removal mechanism have rarely considered the properties of abrasive particles; thus, there is insufficient theoretical guidance on the process optimization, resulting in energy waste during the cleaning process. Therefore, the mechanism in wet blast cleaning of paint was researched in this study, which focused on the effects of abrasive particle shape and size on mechanism. The results indicate that the removal mechanisms of angular and spherical abrasive particles are significantly different, and that of angular abrasive particles is not affected by the particle size, whereas that of spherical abrasive particles is significantly affected. The main removal mechanism for all angular abrasive particles is brittle fracture caused by large impact stresses. For large spherical abrasive particles (≥60-mesh), the main mechanism is brittle fracture due to the intersection of longitudinal-through fatigue cracks and interface cracks, and for small spherical abrasive particles (≤80-mesh), it is brittle fracture due to fatigue cracks and impact cracks. This study provides good insight into abrasive particles and serves as a good basis for exploring the process parameters for wet blast cleaning.

Preparation of the Surface of Long-Dimensional Rods of Hydro-Cylinders for Thermal Spraying Using an Abrasive Jet

Preliminary cleaning of the surface of hydraulic cylinder rods is of great importance for subsequent coating. The most widely used surface preparation for thermal spraying is jet-abrasive treatment. The shot blast modes provide the hardness and strength of the material being processed. The impact of the abrasive makes the surface rough, increasing the contact area. Experimental studies of jet-abrasive processing of the hydraulic cylinder rod surface, as well as its activation for the thermal spraying, were carried out. The prepared surface of the rod for thermal spraying must meet the requirements for surface roughness and the size of the hardened layer at work. The experiments made it possible to identify the optimal modes of jet-abrasive treatment, which affect surface roughness and abrasive penetration of abrasive. To obtain the desired roughness values, it is preferable to use the following: a steel shot with an abrasive particle size in the range of 0.3–1.5 mm, taking the compressed air pressure in the range of 0.4–0.7 MPa; processing time—within 3.5–5 min; counterflow angle with the surface—70–90°; consumption of abrasive particles—300–500 kg/h. A special installation for jet-abrasive processing has been designed, which makes it possible to restore the surfaces of long rods by thermal spraying directly at the site of operation of the large machines.

Effect of micro and nano-sized ZrSiO4 particles on the friction and wear properties of polymer matrix composites

Abstract In this study, the size effect of zircon (ZrSiO4) on the tribological characteristics of polymer matrix friction composites were investigated. Hence, four friction composites containing micro and nano-sized zircon particles (5 and 10 wt%) were developed and produced using powder metallurgy method. Their wear and friction characteristics were examined using a friction-wear test device. The weight loss and specific wear rate were measured and compared with that obtained for microsized zircon particles. The surfaces of samples were analyzed using a scanning electron microscope, and less wear was observed in the samples containing nano-sized zircon particles. The results revealed that the size of abrasive particles plays a key role in enhancing the friction coefficient and friction stability.

Research on Surface Quality of 38CrMoAl Polished Based on Abrasive Water Jet

Because the screw surface is slender and complex, it is difficult to process by traditional polishing methods. In order to improve the surface quality of screw, the abrasive water jet polishing (AWJP) technology was used to polish 38CrMoAl steel, which is commonly used in screw. The effects of different inlet pressure, target distance and abrasive particle size on surface roughness are analyzed. The experimental results show that with the increase of inlet pressure, the surface roughness first decreases and then increases. With the increase of target distance, the surface roughness first decreases and then increases. The smaller the abrasive particle size, the better the polishing effect.

Experimental investigation on simultaneous machining of EDM and ECM of Ti6Al4V with different abrasive materials and particle sizes

In view of the difficult machining characteristics of titanium alloys and the limitations of sequential EDM/ECM machining, taking NaNO3 salt solution with low conductivity as the working fluid, the simultaneous machining of EDM and ECM (SEDCM) assisted by abrasive particles was carried out. Firstly, the effects of the electrical conductivity of the working fluid, the abrasive material, and particle size on material removal rate (MRR), tool wear rate (TWR), surface roughness (Ra), and surface morphology of SEDCM were investigated. Then, SiC abrasive with particle size of 50 μm was selected to add in the working fluid of SEDCM, owing to the unique properties of SiC in comparison with Al and Cu abrasive particles. The effect of process parameters, such as peak current, pulse on time, abrasive concentration, and gap voltage, was optimized using Taguchi-based grey relational analysis. The multi-objective optimization of MRR, TWR, and Ra was converted into the optimization of a single grey relational grade. Finally, based on the grey relational grade, the optimal combination of peak current, pulse on time, abrasive concentration, and gap voltage was predicted and verified by experiments. The results show that the comprehensive machining effect is better when the conductivity of working medium is 300 μS/cm, as long as other electrical parameters and experimental conditions are the same. Compared with Cu and Al abrasives, SiC abrasive has the lowest tool wear rate and the best surface quality, even with the worst material removal rate. Moreover, MRR, TWR, and Ra were obviously improved at the optimal parametric combination of peak current 1.5A, pulse on time 15 μs, abrasive concentration 5 g/L, and gap voltage 40 V by implementing Taguchi-based grey relational analysis.