Abrasive Particle Size Research Articles

Investigating the Effects of SiC Abrasive Particles on Friction Element Welding

The use of dissimilar materials is increasing exponentially in the automotive industry due to the possibility of achieving weight reduction from the multi-material design. Friction Element Welding (FEW) is an advanced solid-state joining technique employed for joining dissimilar materials using a friction element. The processing time of FEW is relatively higher than a few of its competitive joining techniques, with the cleaning step contributing to the majority of the processing time. The current research investigates the effect of SiC abrasive particles on the processing time of FEW and its joint strength. The experimental results show a decrease in the processing time and an increase in the joint strength by reducing the abrasive particle size and the volume fraction of the abrasive particles used. When subjected to tensile loading, one of the samples showed interfacial failure, whereas others exhibited button pull-out failure. The best case from the experiments was chosen for comparison with the standard FEW test, which did not involve abrasives. The comparison shows a 14.3% reduction in processing time with a 10.8% increase in joint strength using abrasives. Inspection of the microscopic images revealed the presence of the SiC phase at the periphery of the friction element around the weld zone and the formation of a defect-free joint. The microhardness test detected a higher hardness along the weld zone for the case involving abrasives compared to the standard FEW test. The hardness data support the higher joint strength results obtained for the FEW joints formed with the abrasives.

Ultrasonic abrasive polishing of additive manufactured parts: An experimental study on the effects of process parameters on polishing performance

The rough surface of metal parts produced by the powder-based layered Additive Manufacturing (AM) technology such as Selective Laser Melting (SLM) is an important problem that needs to be solved. This study introduces obvious improvements in the surface quality of the AM parts by means of ultrasonic abrasive polishing (UAP), which uses cavitation collapse and micro-cut of abrasive particles for finishing surfaces. Experiments were conducted using the orthogonal experimental design method with an L_9(3^4) orthogonal array to investigate the effects of ultrasonic power, machining time, abrasive particle size, and particle concentration on surface roughness Ra and material removal rate (MRR). The wear of the abrasive particles in the slurry was also studied. IN625 nickel-based alloy specimen manufactured by Selective Laser Melting (SLM) was chosen as the target workpiece. The results show that when the ultrasonic output power was too high, both surface quality and machining efficiency were deteriorated. And the surface roughness Ra was not further improved by just increasing the machining time. Severe cavitation erosion occurred in the polishing process and created leftover pits on the workpiece surface, which has a large influence on Ra. The size and amount of the abrasive particles should be within a certain range, which is helpful for material removal and improving the polishing performance. The work is useful for studying the influential process parameters involved in UAP and finding out the appropriate conditions.

Effect of Abrasive Grain Concession on Micromechanical Behavior of Lapping Sapphire by FAP.

Aiming at exploring the material removal mechanism for sapphire using diamond abrasive grains at the microscopic level, this paper modeled and analyzed the microscopic yield behavior of diamond abrasive grains in the FAP grinding process of sapphire. Molecular dynamics were used to simulate the effects of abrasive particle size on the cutting force, potential energy, and temperature in the Newtonian zone during micro-cutting. The effect of different abrasive particle sizes on material removal was analyzed through experiments. The simulation results show that the abrasive particle radius was 12 Å, the micro-cutting force reached more than 3500 nN, while the cutting force with an abrasive particle radius of 8 Å only reached 1000 nN. Moreover, the potential energy, cutting force, and temperature in the Newtonian zone between the sapphire crystal atoms also increased. The results showed that the material removal rate saw a nonlinear increasing trend with the increase in particle sizes, while the surface roughness showed an approximately linear increase. Both of them showed a similar trend. The experimental results lay a theoretical basis for the selection of the lapping process parameters in sapphire.

Effect of abrasive particle size on the tribological behavior of thermal sprayed WC-Cr3C2-Ni coatings

In order to improve the wear performance of ball mill liners, two types of WC-Cr3C2-12Ni coatings with different Cr3C2 contents were prepared based on high- velocity oxygen fuel (HVOF) spraying technology. The three-body abrasive wear behavior of the WC-10Cr3C2-12Ni (W10N) and WC-30Cr3C2-12Ni (W30N) protective coatings under different particle sizes was systematically evaluated. Results show that the phase composition, microstructure, and mechanical properties of WC-Cr3C2-12Ni coatings were influenced by Cr3C2 content. A large amount of WC phase with good dispersion and fine morphology must be maintained to improve the wear resistance of the coatings. The friction coefficient of both coatings was the lowest when the abrasive particle size was 12.0 µm, but it was still lower than under the no-particle condition. In addition, the friction coefficient of the W30N coatings fluctuated when the particle size were 1.5 and 4.0 µm. The primary wear mechanisms of the two coatings without particles were oxidation wear and fatigue wear, respectively, and the microstructure unevenness and low WC volume fraction led to serious wear of the W30N coatings by preferential removal of the binder phase and pull-out of the WC. The wear mechanisms of the coatings after adding small to large particles were as follows: abrasive particles protected the coatings; rounded the WC grains; and planed the coating to exfoliate in layers. By contrast, the wear resistance of the W10N coatings was obviously superior to that of the W30N coatings. Importantly, the particle size influenced the counter-balls more than the coatings. This study provides potential applications for the surface protection and life extension of ball mill liners.

Surface and subsurface microscopic characteristics in sapphire ultra-precision grinding

To investigate surface and subsurface microscopic characteristics, the ultra-precision grinding experiments of sapphire were carried out by the minimal parameter cycle method. The effects of grinding wheel grit sizes and grinding cycles number on surface and subsurface characteristics were investigated. It was confirmed that the full ductile damage-free surface with Sa10nm can be achieved, and the microscopic characteristics of rough grinding and ultra-precision grinding surfaces are different. The effect of abrasive particle size on surface roughness and grinding wheel profile wear was discussed. Moreover, the subsurface characteristics were surveyed through molten KOH corrosion, the subsurface marks and subsurface damage were observed. The subsurface damage was dominated by median cracks, it can be observed under the ductile surfaces.

Effects of Particle Impingement and Coarse Particle Abrasion on Wear Performance of White Cast Irons in Sliding Bed Applications

Particle impingement angle variations during interactions between abrasive particles and wear plates affect the wear rate and cause uneven abrasion of liners in sliding bed applications—a typical condition in ore transfer chutes. Inner circumference abrasion tests (ICAT) were performed on specimens placed at various angles to abrasive bed flow direction to analyze these effects in laboratory environments. The ICAT results indicated that wear performance diminishes for increasing impingement angles within the range studied. In all impingement angles, carbide volume fraction (CVF) showed significant direct influence on the alloy performance in contrast to Cr/C ratio of the alloy showing only minor effects. Abrasion performance versus CVF trends for white cast iron and abrasive combinations were observed to show performance reversals in the ICAT due to preferential abrasion of matrix. Abrasive type (hardness) was shown to be a factor for performance reversal in that study, with abrasive particle size being suggested to be another factor. To determine this, the current study scrutinizes coarse particle abrasion in addition to fine particle tests. Dissimilar to fine basalt, coarse particle ICAT results show monotonic wear life increase versus CVF, with no performance reversal.

Investigation on the Basic Characteristics of Semi-Fixed Abrasive Grains Polishing Technique for Polishing Sapphire (α-Al2O3).

Single-crystal sapphire (α-Al2O3) is an important material and widely used in many advanced fields. The semi-fixed abrasive grain processing method based on solid-phase reaction theory is a prominent processing method for achieving ultra-precision damage-free surfaces. In order to develop the proposed method for polishing sapphire, the basic characteristics of the semi-fixed abrasive grains polishing tool for polishing sapphire were determined. Weight analysis was used to study the influence rules of parameters on surface roughness and material removal rates using an orthogonal experiment. Then, the optimized polishing tool was obtained through a mixture of abrasive particle sizes to reduce the difficulty in molding the polishing tool. Finally, polishing experiments using different polishing tools were carried out to investigate polishing performance by considering the surface roughness, material removal rate and the surface morphology during polishing. The results showed that (1) external load affects the surface roughness and material removal rate the most, followed by abrasive particle size, sand bond ratio, revolution speed of the workpiece and he polishing tool; (2) the difficulty in manufacturing the polishing tool could be reduced by mixing larger abrasive particles with small abrasive particles; (3) the polishing tool with 200 nm and 1 μm particle sizes performed best in the first 210 min polishing.

The three-point eccentric magnetorheological polishing technology for hard brittle alumina ceramics

Abstract. This work presents the design of a pressurised three-point eccentric magnetorheological polishing (MRP) device, for alumina ceramics' hard and brittle characteristics, and a carrier disc magnetic field generator and a single closed-loop uniform magnetic field generator for a more uniform and increased magnetic field distribution. When compared with the traditional gap type, this device considerably enhances polishing efficiency. This apparatus has also been used to explore the mechanism of MRP. Static magnetic field simulations were conducted, and the fundamentals of the three-point eccentric magnetorheological process were addressed. Alumina ceramics were polished with a three-point eccentric wheel MRP equipment. Polishing tests were conducted to explore the effects of rotational speed, working pressure, abrasive type, abrasive particle size and polishing duration on polishing properties, and optimised polishing parameters were established. The surface roughness (Ra) of the samples was dramatically reduced from 500 to 22.41 nm using the three-point eccentric MRP device. The pit markings on the alumina ceramics' surface vanished after polishing. Therefore, the approach has considerable polishing potential for hard and brittle materials that can be nanofabricated with minimal surface sub-damage.

Effect of pumice stone and pearlite abrasives characteristics on denim abrasion

The manufacture of abrasives based on waste grains of pumice stones and pearlites represents the aim of this work is to minimize both the cost of the product and to recover industrial waste that harms the environment. We also used a non-woven based on cellulosic fibers as reinforcement and three types of resins (polyurethane, acrylic, and polyester). Obtaining these products is designed by two processes (by spraying and by coating). The effect of the manufacturing process, the type and size of the grains on the abrasive wear of denim fabrics, the material removal rate (MRR), and the surface morphologies obtained were quantitatively evaluated. A chemical analysis (FTIR) and a thermal analysis were carried out (ATG/DSC). Scanning electron microscopy (SEM) was performed to see the appearance of these grains and measure their diameter. Inductively Coupled Plasma Mass Spectrometry (ICP/MS) analyses show that pumice grains contain more calcium atoms than pearlite grains. The different abrasion grains were compared according to their polishing effect. We note that the abrasive manufacturing process, type, and size of abrasive particles affect the MRR. Pumice grits allow for deeper polishing compared to other grits.

Parameter optimization of ultrasonic vibration polishing K9 optical glass based on ultrasonic atomization

To further improve the surface finish and processing efficiency of optical components, ultrasonic vibration technology is frequently combined with conventional processing and the process parameters that play a critical role in this composite processing are identified. This research proposes an ultrasonic vibration polishing method based on ultrasonic atomization (UA-UVP). The polishing performance of K9 optical glass is increased by ultrasonic atomization (UA) assisted by polishing solvent for ultrasonic vibration polishing (UVP). Orthogonal experiments are used to study the effects and variation laws of the flow rate of ultrasonic atomization (Q), the gap distance between the polishing tool and workpiece (G), ultrasonic electro spindle speed (W), abrasive particle size (D) and ultrasonic amplitude (A) on surface roughness (SR) and material removal rate (MRR), respectively. When these two polishing characteristics are considered together, the optimization of polishing parameters becomes complicated. Therefore, the principal component analysis (PCA) and grey relational analysis (GRA) methods were employed to the optimal experimental combination as Q:18 ml/min, G: 5 μm, W: 4000 r/min, D: 0.5 μm, A: 8 μm. The experimental results showed that Ra and MRR were measured as 10.466 nm and 0.473*10^8 μm3/min, respectively. Compared with the best experimental combination of orthogonal experiments, the improvement rates of SR and MRR were 26.65% and 25.80%, respectively. Overall, the application of ultrasonic vibration technology contributes to enhancing the uniform distribution of polished abrasive particles and improving the polishing characteristics.

Analysis of abrasive grain size effect of abrasive belt on material removal performance of GCr15 bearing steel

The effect of abrasive grain size on the material removal performances of the grinding surface was studied by theoretical modeling and grinding experiments. The results indicted that a smaller abrasive grain size of the abrasive belts led to smaller microscopic contour height and surface roughness of the ground surfaces, fewer curl chips, and more spherical chips. The smaller grain size also led to smaller macroscopic grinding depth and material removal rate. There was an approximately linear relationship between the macroscopic grinding depth and material removal rate during plane grinding. The slope was related to the abrasive grain size. Grinding force, vibration, vision, and sound signals could distinguish the macroscopic material removal changes caused by abrasive belt particle sizes.

Effect of Alkali Metal Ion on Chemical Mechanical Polishing of LiTaO3

Low material removal rate (MRR) and poor surface quality are the two main problems in ultra-precision machining of LiTaO3 wafer. In order to improve the MRR of LiTaO3 in chemical mechanical polishing (CMP), the effect of alkaline metal ion in slurry on the MRR of LiTaO3 was studied. The results show that adding an appropriate concentration of alkali metal ions to the slurry can increase the abrasive particle size and reduce the electrostatic repulsion between the abrasive and the wafer surface so as to enhance the mechanical effect. At mean time, Li+ replaced by K+ on the LiTaO3 wafer to produce easily removed KTaO3. Adding a certain amount of alkaline metal ion to the slurry improves the MRR of LiTaO3 wafer. Finally, when CMP was performed in slurry (pH 9) with a composition of 10 wt% SiO2 and 0.07 M KCl, the MRR of LiTaO3 is 111 nm min−1 and the surface roughness (Sq) is 0.3 nm.

Tribological effects of loose alumina abrasive assisted sapphire lapping by a fixed agglomerated diamond abrasive pad (FADAP)

The tribological effects between a fixed abrasive pad (FAP) and a workpiece can effectively maintain the self-conditioning process of the FAP in real time. However, the FAP is easy to be glazed along with the long-term lapping processes of hard-to-process ceramic materials. This paper proposed a novel method of loose abrasive assisted fixed agglomerated diamond abrasive lapping (LA-FADAL) to achieve efficient and stable lapping processes of sapphire. LA-FADAL tests with a fixed agglomerated diamond abrasive pad (FADAP) were carried out by changing the particle size and volume fraction of loose alumina abrasives in lapping slurries. The influences of the different alumina abrasives on the processing performance of the FADAP were discussed. Material removal mechanisms in the LA-FADAL processes were proposed based on the tribological effects of loose alumina abrasive assisted sapphire lapping by the FADAP. The loose alumina abrasives with the similar size as the diamond grains embed in the surface of the fixed AD abrasive could not remove sapphire materials directly and effectively by mechanical actions, mainly played a role of dressing the FADAP to enhanced the self-sharpening ability of AD abrasives, and further improved the self-conditioning ability of FADAPs.

Experimental investigation of the effect of insert spacing on abrasion wear resistance of a composite

Reducing abrasive wear is crucial to minimising economic losses in bulk solids handling, particularly in the mining industry. The present study investigates the wear behaviour of macro-scale composites, consisting of hard inserts equi-spaced in a soft matrix, with a length-scale comparable to the size of abrasive particles. The experiments explored the effect of insert spacing on the formation of protective particle layers to reduce wear. Hardened tool steel inserts were embedded in a soft aluminium matrix. The spacing between inserts decreased with increasing volume fraction of inserts (8, 23 and 40 vol%). An instrumented dry sand rubber wheel test was used to conduct accelerated wear tests, and to measure the thickness of the protective abrasive particle layer formed during the tests. The soft aluminium matrix wore preferentially, leaving the tool steel inserts standing proud. The exposure height of the inserts reached a steady state for extended wear stages. Interestingly, the composites with 23 and 40 vol% of inserts showed significantly less wear than predicted by the rule of mixture. When the insert spacing was equal to the abrasive particle size, the thickness of the abrasive particle layer was larger than for specimens without inserts. This study reveals that the spacing between the inserts, with respect to the abrasive particle size, is an important design parameter for the development of enhanced wear resistant composites.

Model-Based Optimization of CMP Process Parameters for Uniform Material Removal Selectivity in Cu/Barrier Planarization

Chemical mechanical planarization is a process of achieving planar surfaces in the semiconductor manufacturing industry. The planarization of a surface is achieved by material removal from the wafer surface. The material removal depends on material properties and the process input parameters. Several studies have investigated the role of slurry chemistry to achieve a certain material removal selectivity of different materials on a patterned wafer. Here we propose a methodology of achieving planar patterned surface of Cu/Mn/MnN system using a model-based optimization for mechanical process parameters. The parameters include applied force, slurry solid concentration, and abrasive particle size. The methodology has been developed via optimization using a genetic algorithm. The proposed methodology suggests that a lower downforce is the key parameter to achieve the desired material removal selectivity and planarity. The first part of the study suggests a low material removal rate (MRR) to achieve a lower standard deviation in MRR. The second part investigates the standard deviation in the thickness removed in the average time needed to remove a known thickness of the materials under consideration. It has been found that the application of lower downforce can also minimize the standard deviation in the thickness removed and a planar patterned surface can be achieved.

Role of the smear layer in adhesive dentistry and the clinical applications to improve bonding performance.

Currently, dental adhesives can be divided into two systems; a smear layer-removal approach with etch-and-rinse adhesives or a smear layer-modified approach with self-etching adhesives. After phosphoric acid etching, the smear layer is completely removed. More attention is, however, required when using self-etching adhesives. The smear layer is partially demineralized by the weak acidic monomer and subsequently incorporated into the hybrid layer. Therefore, the characteristics of the smear layer play an important role on the bonding performance of self-etching adhesives. Such characteristics, for instance, smear layer thickness and smear layer density, are influenced by many factors, e.g., instruments used for dentin surface preparation, cutting speed, and the abrasive particle size of the cutting instruments. This review discusses the contributing factors that affect the smear layer characteristics, and the influence of the smear layer on the bonding performance of dental adhesives. Also, the application techniques regarding how to improve the bonding performance of self-etching adhesives – the smear layer removal by using chemical agents, or the modification of the adhesive application procedures – are provided.

Research on quality control of precision machining straight internal gear by abrasive flow based on large eddy simulation

Traditional finishing technology is difficult to realize the precision machining of complex geometric parts. Abrasive flow machining technology solves this problem well. Taking the spur internal gear as the research object, the wall shear force, static pressure, dynamic pressure, and abrasive velocity vector of the internal channel of the straight internal gear under different inlet velocity, abrasive concentration, and abrasive particle size are analyzed by using the large eddy simulation method, and the action law of different parameters on the machining of straight internal gear by solid–liquid two-phase abrasive flow is discussed. At the same time, the orthogonal test was carried out. The results show that the solid–liquid two-phase abrasive flow machining technology can effectively remove the burrs, pits, and bulges on the tooth surface of spur internal gear, reduce the tooth surface roughness, and improve the surface quality. The optimal combination of processing parameters and the primary and secondary order of various factors affecting processing are obtained by range analysis and analysis of variance. The regression equation is constructed by regression analysis to verify the effectiveness and accuracy of the model, which provides theoretical support and data reference for actual processing and production.

Analysis of abrasives on cutting edge preparation by drag finishing

Cutting edge preparation has become more important for tool performance. The micro-shape, radius and surface topography of the cutting edge play a significant role in the machining process. The cutting edge of solid carbide end mills has some micro-defects after grinding. For eliminating aforementioned problem, this study investigates drag finishing (DF) preparation for solid carbide end mills to reconstruct cutting edge micro-geometry. This paper is to present the design of DF experimental setup and analyze the characterization of various abrasive media (K3/600, K3/400, HSC 1/300 and HSO 1/100) on the evolution of the surface/roughness along the cutting edge. In parallel, the mechanism of material removal and the kinematics trajectory of the drag finishing are presented. In fact, the form factor (also called as “K-factor”) of the cutting edge micro-geometry is quantified. Comparing with four lapping media, the higher material removal rate (MRR) and the lower surface roughness are obtained by HSO 1/100 abrasive process. The results show that the cutting edge K-factor, MRR and surface topography are influenced by the abrasive particles size, composition and process time.

Effect of nano filler addition on carbon reinforced polymer composite

Now a day’s nano-composite field has become a wide area of research and development. An attempt has been made to investigate the erosion wear characteristics of carbon reinforced composite filled with varying weight proportions of nano fillers (Al2O3 + SiC). The specimens were prepared as per ASTM standards manually by the addition of filler as 1 wt% and 2 wt% and succeeded by the compression molding process. By changing the parameters like size of erodent, impact velocity, time and impingement angle erosion tests were conducted. The results indicated that, addition of nano filler particles into C-E composite increased the wear resistance significantly, because of improved surface area. By optimizing the process variables leads to least erosion rate for the composites which can be analyzed by using Taguchi (L27 orthogonal array) technique. Grey Relational Analysis (GRA) is used in order to find the significance of many factors like abrasive particle size, impingement angle, time, filler percentage and impact velocity. Observation indicates that erodent size influences more on erosive behavior of C-E composite. Optimal factor level has been suggested after complete analysis.

The Use of Surfacing Materials to Increase the Durability of Disc Harrow Working Elements

Introduction. For surface tillage operation there widely used disc harrows, working bodies of which are discs wearing out during operation. The wear intensity of discs depends on the wear resistance of their working surfaces, working modes and properties of the cultivated soil. It has been found that an effective way to increase the life of discs is surfacing them with wear-resistant materials. The aim of the work is to study the wear out of surfacing materials, which can be used to harden discs and to make recommendation for the use of these materials in the repair departments of agricultural enterprises. Materials and Methods. Surfacing with electrodes T-590 and powder wires PP-Np200Kh15S1GRT, VELTEK-N560.02 and PP-Np280Kh9F7SG4 were taken as test materials. For wear tests of materials in abrasive mass, there was used an apparatus to simulate the moisture content and composition (sandy loam or loam) of the soil. In the disk-pad tests, the effect of abrasive particle size, load and sliding friction velocity on the wear of the materials was studied. In field tests, wear of the disks made of 65G steel, surfaced toothed and solid disks were monitored. Results. Laboratory studies of the materials revealed the effect of soil moisture and composition, load, abrasive grit and sliding friction velocity on wear. The main factor determining the wear resistance of materials is their structural state. The indexes of wear resistance of surfacing were determined during the laboratory tests and confirmed by field tests. Discussion and Conclusion. Surfacing with flux-cored wire PP-Np280Kh9F7SG4 has the highest wear resistance of the studied materials. The technology of hard-facing disks with modern materials, in particular with flux-cored wire PP-Np280Kh9F7SG4, can be implemented in repair departments of agricultural enterprises when they have the equipment for hard-facing and sharpening of working surfaces.