Abrasive Slurry Research Articles

Enhancement of speed of surface roughness improvement by using a two mixed abrasive slurry method to polish glass surfaces

Enhancement of speed of surface roughness improvement by using a two mixed abrasive slurry method to polish glass surfaces

TRIBOLOGICAL STUDY ON SLURRY ABRASIVE WEAR BEHAVIOR OF NONWOVEN VISCOSE FABRIC COMPOSITES WITH DOE APPROACH

Nowadays, the demand for needle-punched nonwoven fabrics has been increasing, especially in the areas of high-performance composites as reinforcement due to their potential of imparting high [Formula: see text]-directional strength, easy resin absorption, light weight, and low cost. In this study, needle-punched nonwoven viscose fabric-reinforced epoxy composites are prepared by varying the area density of fabric mat (100[Formula: see text]gsm, 200[Formula: see text]gsm, 300[Formula: see text]gsm, and 400[Formula: see text]gsm) at constant fabric loading of 30[Formula: see text]wt.%. The effects of area density on mechanical and slurry abrasion behavior of composites are studied under controlled laboratory conditions. It is observed that the mechanical properties and abrasive wear resistance under steady-state condition has been improved with the increase in area density of fabric mat. Furthermore, experimental design through Taguchi’s L[Formula: see text] orthogonal array is applied to find out the optimal parametric combination for minimum wear rate. It is also observed through the analysis that silica sand size and sliding velocity are the most influential factors for wear rate.

Fluoride Release from Two High-Viscosity Glass Ionomers after Exposure to Fluoride Slurry and Varnish.

The effect of brushing with different fluoride slurries on the fluoride release (FR) of different high-viscosity glass ionomer cements (GICs) was investigated. Fifty-eight discs were fabricated from two high-viscosity GICs (GC Fuji IX (F9) and 3M ESPE Ketac-fil (KF)). Five specimens from each brand were used to measure Vickers microhardness and the remaining were randomly assigned to one of four groups (n = 6) based on two-factor combinations: (1) fluoride concentration in the abrasive slurry (275 or 1250 ppm fluoride as NaF) and (2) immersion in a 22,500 ppm fluoride-containing solution. Specimens were brushed for a total of 20,000 strokes over 4 days with daily FR measurement. Data were analyzed using analysis of variance and Bonferroni tests (α = 0.05). Baseline FR and microhardness values were different between the two tested material brands. Exposure to a 22,500 ppm solution was associated with higher FR but not the exposure to 1250 ppm slurries. Brushing and immersion of glass ionomer cements in a 22,500 ppm F solution led to higher FR that was more sustained for KF. Type of the glass ionomer, progressive brushing, and fluoride varnish affected FR but not the fluoride content in the abrasive slurry.

Tribological Behavior Analysis of the ISO 5832-1 Austenitic Stainless-Steel Treated by Optical Fiber Laser Used for Biomedical Applications

The present work analyzed the influence of an optical fiber laser surface treatment process on the tribological behavior of the ISO 5832-1 austenitic stainless-steel, basing on the wear volume and friction coefficient. Specimen of this biomaterial were treated by alternating the laser frequency, in order to find out a condition that improves its tribological resistance. Ball-cratering micro-abrasive wear tests were carried out with a test ball of AISI 316L stainless-steel, used as counter-body, and an abrasive slurry prepared with abrasive particles of black silicon carbide (SiC) and distilled water. The micro-abrasive wear tests results indicated that: i) the hardness of the ISO 5832-1 austenitic stainless-steel increased as a function of the laser frequency, decreasing, consequently, the wear volume, as predicted by Archard’s Law; ii) the friction coefficient did not present a proportional behavior with the increase of the optical fiber laser frequency; iii) the best condition to improve the wear resistance of the ISO 5832-1 austenitic stainless-steel was obtained adopting an optical fiber laser frequency of 350 kHz, being reported the lower wear volume.

Study on Dynamic Strain Distribution in Rock Broken by Abrasive Slurry Jet

To reveal the stress and strain field in rock under abrasive slurry jet (ASJ) impacting, this paper carried out experiments to measure the dynamic rock strain using a novel strain measurement approach, which is the non-contact strain measurement system. Moreover, it was compared with the theoretical analysis of stress propagation in rock. The results showed that dynamic strain will propagate within rock in the form of spherical waves, whose maximum value is proportional to the jet pressure and inversely proportional to the square of the propagation distance. In the process of ASJ impacting rock, strain will increase from zero to a maximum value in milliseconds. Dynamic strain in rock is fluctuates due to the release of internal stress caused by the rock crushing, which can reflect that rock will be broken by ASJ in the form of stepped-failure. The paper reveals the dynamic strain distribution in rock broken by ASJ and provides a new idea and method for studying the rock failure mechanism under ASJ impacting.

A numerical study on flow characteristics and rock stress in abrasive slurry jet impingement

To apply abrasive slurry jet (ASJ) in rock drilling calls for in-depth understandings on the mechanism of impingement process. A fluid–structure coupling model that combines multi-fluid model and finite element method was established for a set of numerical investigation. The simulation results show that entrained air contributes to the divergence by successive disturbing on the jet flow. Subjected to the jet impact, the stress field of rock structure is affected by the standoff distance, abrasive particle diameter and crack in rock material. On the other hand, we adopt both first strength criterion and Drucker–Prager criterion for the elastic–plastic rock material to evaluate the stress state of rock under a high-speed jet impact. It is found the onset of rock damage is primarily attributed to a brittle tensile fracture at crack tip and a plastic failure in the crack front, tending to initiate from a smaller-length-scale crack. The flow field and rock stress are characterized to provide a numerical basis for the parametric optimization of ASJ impinging rock as well as other elastic–plastic materials.

Badania docierania powierzchni płaskich elementów ceramicznych z wymuszonym dawkowaniem zawiesiny ściernej

The issues related to the forced dosing system of the abrasive slurry in single-disk lapping are presented. This system allows dosing of a suspension with different fluid viscosities. The innovative system developed was adapted to work on the Abralap 380. The advantages of this type of abrasive sling dosing system and the procedure for planning testing of lapping of flat elements from technical ceramics, on the example of Al2O3 treatment, are described. Selected results of defect investigations are presented, which were subjected to detailed statistical analysis.

Investigation of particle agglomeration with in-situ generation of oxygen bubble during the tungsten chemical mechanical polishing (CMP) process

This research investigates abrasive particles agglomeration via interaction between O2 bubbles and slurry abrasives during the tungsten chemical mechanical polishing (W CMP) process. The abrasive particles in slurry were highly agglomerated due to higher volumes of O2 bubbles produced in the reaction between the catalyst Fe(NO3)3 and the oxidizer H2O2. Results obtained from a gas pressure sensor confirmed the generation of higher O2 volume via the decomposition of H2O2 at a high catalyst concentration and an increase in reaction temperature. The decomposed O2 volume rate at 80 °C was reported at the maximum value of 2.0 × 10−2 L/s at 120 ppm as compared to the moderate and minimum rates of 3.5 × 10−3 and 3.2 × 10−4 L/s for catalyst concentrations of 60 and 30 ppm, respectively. Images of O2 bubbles, captured using a high-speed camera, exhibited subsequent enhancement in average O2 bubble diameters of 91, 427, and 503 μm at 25, 60, and 80 °C, respectively. Analysis of surface scans confirmed large abrasive particles contamination on the TEOS wafer with an increase in the O2 bubble flow rate and bubbling time. Also, large abrasive particles agglomeration was observed in the presence of O2 bubbles as compared to no bubbles, as measured by dynamic light scattering DLS. It is believed that higher hydrophilicity of abrasive particles with O2 bubbles increased the adhesive force between the abrasive particles and the in-situ generated O2 bubbles. The high drag force generated during the collapse of O2 bubbles is essentially attributed a strong attractive force between the abrasive particles and the TEOS wafer which strongly binds with the abrasive particles and intensifies the defect level as particle agglomeration.

Micro-abrasive wear resistance of the duplex expanded austenite layer phases produced by plasma nitrocarburizing

The present study investigates the influence of the phases of the duplex expanded austenite layer on the micro-abrasive wear resistance of the plasma nitrocarburized AISI 304 austenitic stainless steel. Plasma nitrocarburizing was performed by using a gaseous atmosphere containing 80% N2 + 2% CH4 + 18% H2, producing precipitate-free duplex expanded austenite layers (γN+γC) at 375 °C and 430 °C, composite layer (γN+γC + Fe3N-ε + CrN) at 475 °C and nitride layer (Fe4N-γ’ + CrN) at 555 °C. Each phase of duplex expanded austenite layer was produced in separate gaseous atmospheres at 375 °C, carbon expanded austenite monolayer (γC) in 2% CH4 + 98% H2 and nitrogen expanded austenite monolayer (γN) in 80% N2 + 20% H2. The abrasive wear behavior was measured in a free ball micro-scale abrasion tester with fine-particle abrasive slurry of SiO2 which allowed to evaluate wear resistance and wear mechanism of the produced layers. The results showed that the thicker duplex expanded austenite layer which was precipitate-free (γN+γC), produced at 430 °C, displayed the highest wear resistance. From analyses of the individual monolayers, two wear mechanisms were found: two-body abrasion related to the nitrogen-rich phase (γN) and three-body abrasion associated to the carbon-rich phase (γC).

Tribo-mechanical and physical characterization of filament wound glass/epoxy composites

The present research aims to investigate mechanical, physical and tribological properties of filament wound Glass Fibre Reinforced Polymer (GFRP) composite pressure vessel as per respective ASTM standards. Here test coupons prepared from GFRP vessel are subjected to tensile, compression, flexural and impact testing to investigate mechanical properties. The physical properties are studied from density, ignition loss and water absorption tests. The tribological study was carried out using abrasive slurry erosion tester. All tests carried out in this study are as per respective ASTM standard. The results obtained from various mechanical testings are satisfactory and also almost equal in strength with respect to metallic pressure vessels. Particularly from impact testing, the strength of sea water treated sample has considerably increased. Fractography study was conducted on failed samples to study various mode of failure in detail. The physical characterization has elaborated the behavior of filament wound GFRP material under moisture environment which has observed a maximum of 0.5% water absorption rate. As per ignition loss study which reveals about 95%-98% weight of ignition loss is recorded, which indicates perfect fibre to resin ratio and almost nil or least % of void content. The slurry erosion test results are within the expected range and maximum wear of 9.67% is recorded under extreme case. The overall study reveals that the presence of voids, non-uniform distribution of fibre and matrix have an impact on the outcomes of many mechanical properties. From the above study we can conclude that filament wound GFRP pressure vessel can be used in many applications since it is a non-hydrophobic, better wear resistant and several strength parameters have also improved or unaltered under rigorous testing conditions.

Use of an Abrasive Water Cavitating Jet and Peening Process to Improve the Fatigue Strength of Titanium Alloy 6Al-4V Manufactured by the Electron Beam Powder Bed Melting (EBPB) Additive Manufacturing Method

Metal components made by additive manufacturing have large inherent surface roughness, and, as such, their strength and fatigue life can be reduced significantly versus wrought products. In order to improve these properties, a novel mechanical surface treatment that introduces compressive residual stress while simultaneously reducing the surface roughness is proposed. The proposed treatment uses cavitation peening combined with an abrasive slurry. The impact of the kinetic energy-charged abrasive particles, induced by collapsing water cavitation vapor bubbles, produces compressive residual stress, while the abrasive reduces the surface roughness. Plane-bending fatigue tests were carried out to determine the effectiveness of this treatment on the fatigue life and strength of titanium alloy Ti6Al4V manufactured by electron beam melting. It was demonstrated that the fatigue strength of an as-built specimen was improved from 169 MPa to 280 MPa by the proposed treatment.

In-situ fabrication of a UHMWPE nanocomposite reinforced by SiO2 nanospheres and its tribological performance

In-situ fabrication of nanocomposites facilitates the dispersion of nanofillers in organic matrixes by decreasing the agglomeration of nanofillers compared to a mechanical mixing method. UHMWPE nanocomposites filled SiO2 nanospheres (SNS) were in-situ fabricated by a sol-gel method in this work. Their sliding coefficient of friction and wear rate were determined by a high-speed ring-block wear test apparatus against 45# steel under dry friction conditions, and the tribological behaviors at elevated temperature were tested by a slurry abrasion wear configuration. The in-situ filled SiO2 nanospheres presented an excellent dispersion on UHMWPE, and the fabricated SNS/UHMWPE nanocomposites were found a remarkable enhancement in stiffness, glass transition temperature and hydrophobicity. Furthermore, the SNS/UHMWPE nanocomposites exhibited markedly improved tribological performances than the matrix UHMWPE and the referenced sample prepared by a mechanical mixing method: the sliding coefficient of friction was reduced by over 50% than that of the pristine UHMWPE against a 45# steel ring under dry friction, and the mass wear rate was ca. 59% of the UHMWPE matrix determined by a water-bath mortar at an elevated temperature.

Enhancing Ductile-mode Cutting of Calcium Fluoride Single Crystals with Solidified Coating

Positive improvements have been observed during machining brittle materials under high hydrostatic pressure, but the techniques to achieve such desirable effects often utilize complex and expensive equipment or tools. This work presents a cost-efficient method to achieve ductile-mode machining of brittle materials at higher uncut chip thicknesses, by the application of a solidified coating on workpiece surface before a machining process. Orthogonal microcutting experiments were conducted on calcium fluoride single crystals oriented with the (111) plane and an increase in critical uncut chip thickness was observed with the solidified coating. The primary cause has been resolved to be mechanical-related and results in a stabilized microcutting process. Transmission electron microscopy provided evidence of slip deformation occurring in the machined subsurface regions and a layer thickness of subsurface damages reduced by ~ 45% under the influence of the solidified coating. In addition, erratic fluctuations in direction of the resultant machining force were subdued with the applied coating, which is proved to be caused by the compressive stresses induced from the sandwiching of the CaF2 material between the tool and the solidified coating. The proposed technique successfully reduces the cost and pollution in the fabrication process of optical components from the use of coolant in an ultraprecision machining process to the time consumed by eliminating the subsurface damage with abrasive slurries in post-machining polishing.

Study on ASJ Cutting of TC18, Based upon Multivariate Nonlinear Regression and SA-BP-AGA

TC18 titanium alloy has been widely applied, but is considered as a difficult machining material. Taking the kerf angle as the quality criterion, this paper studied the cutting performance of TC18 by the use of an abrasive slurry jet (ASJ), based upon multivariate nonlinear regression and SA-BP-AGA. Cutting experiments were carried out according to the Taguchi orthogonal method. The experimental factors included traverse speed, standoff distance, pressure and slurry concentration, with five levels set, respectively. Meanwhile, a characterization method of the major influencing factors was proposed. A multiple nonlinear regression model and a back propagation artificial neural network (BP) prediction model, based on adaptive genetic algorithm (AGA), were established. The reliability was verified by statistics equations for the 22 groups of the fitting or training model and the three groups of experimental results. The BP-AGA and Simulated annealing algorithm (SA) were used to form a set of prediction optimization systems, called integrated SA-BP-AGA. Finally, the results showed that the main factor influencing the kerf angle is the slurry concentration. BP-AGA is easier to model, offers better robustness and is more accurate than a multivariate nonlinear regression model. The best kerf angle can be predicted by the integration system. The study results can improve the performance for the machining of TC18 by ASJ.

A new integrated numerical modeling approach toward piston diaphragm pump simulation: Three-dimensional model simplification and characteristic analysis

Piston diaphragm pumps are used worldwide to transport abrasive and aggressive slurries against high discharge pressures in the mining, mineral processing, and power industries. Intermittent suction and drainage of the diaphragm, however, can lead to pulsating output pressure, which has caused major problems in the application of these pumps. To improve the accuracy of simulations of piston diaphragm pumps and to enable better simulation of their pressure pulsation behavior, it is necessary to carry out a three-dimensional fluid–structure interaction simulation of the pump fluctuation characteristics. This article proposes a simplified simulation model based on the periodic motion characteristics of a piston diaphragm pump, where a ZMB240 piston diaphragm pump serves as the research object. By simplifying the numerical simulation of the model, we are able to analyze the deformation characteristics and the fluctuation characteristics of the piston diaphragm pump under different initial conditions for the pressure-stabilizing air chamber.

Small Molecule Adsorption on Colloidal Alumina and Zirconia Abrasives Used in Chemical-Mechanical Planarization (CMP) Slurries

Small molecule adsorption on CMP slurry abrasive particles has been investigated previously for silica (1) and ceria (2, 3) abrasives using fluorescence correlation spectroscopy (FCS) and attenuated total reflectance – Fourier transform infrared spectroscopy (ATR-FTIR). The need for further characterization of such adsorptive interactions is dictated by the increasing use of abrasive particles in CMP slurries with minimized hydrodynamic diameters (≤ 10 nm) as a means to reduce surface defects created during CMP processes. Incorporation of ever-smaller abrasive particles in CMP slurries will, however, promote the adsorption of chemical additives on a slurry’s abrasive particles due to the increase in the total abrasive particle surface area. In the present study, FCS and ATR-FTIR are employed in the analysis of small molecule adsorption on colloidal alumina and zirconia abrasive particles. This work is motivated by the widespread commercial use of alumina-based slurries in CMP processes for planarization of deposited copper films on dielectric layers and the proposed use (4) of zirconia abrasives in CMP slurries for metal film removal on dielectric metal oxide materials. The reported FCS studies use fluorescent dyes as probes for adsorption sites on alumina and zirconia colloids dispersed in aqueous solution. Described ATR-FTIR analyses summarize the characterization of molecular interactions driving glycine and picolinic acid adsorption on porous thin films of colloidal alumina and zirconia, respectively. The potential for employing these methods in studies modelling the adsorption of CMP slurry additives on a metal film deposited on a silicon wafer surface is also discussed.

Effects of cooling and lubrication conditions on tool wear in turning of Al/SiCp composite

Al/SiCp composites machining is considerably difficult, owing to the presence of hard particles that result in severe tool wear. The application of different cooling and lubrication methods can offer a favorable change in the tool used in machining of Al/SiCp composites. To study the effects of different cooling and lubrication conditions on the tool wear in the machining of Al/SiCp composites, turning experiments under dry, liquid nitrogen (LN2), minimum quantity lubrication (MQL), cutting oil (Oil), and emulsion environments were conducted, and the mechanisms of tool wear with respect to boundary wear, major flank wear, adhesive wear, and tool breakage were discussed. The results indicate that the MQL and LN2, which exhibit excellent flushing performance, could wash away the chips and SiC particles from the boundary zones of the minor flanks, thus reducing the boundary wear. However, the use of Oil and emulsion promoted the formation of an abrasive slurry that enhanced the three-body abrasion at the boundary zones. In addition, the MQL and LN2, which show excellent lubricating and cooling properties, promoted the reduction of the major flank wear. The formation of worn pits and built up edge(s) (BUE) on the rake faces confirmed the presence of adhesive wear in the turning of the Al/SiCp composite using polycrystalline diamond (PCD) tools, and the cooling effect of MQL and LN2 could not prevent the workpiece material from accumulating in the worn pits and giving rise to the BUE. When turning Al/SiCp composites under LN2 and Oil conditions, the tool breakage was accelerated. The application of LN2 increased the thermal impact and the scratch effect of the SiC particles on the tool faces, aggravating the tool breakage. The rapid tool breakage caused by Oil cutting could be attributed to the reduction of the cutting edge strength that bore the alternating load and thermal impact. Therefore, it is concluded that the use of MQL, which assists in reducing the boundary wear, tool breakage, and major flank wear, is suitable as the preferred cooling and lubrication mode in the turning of Al/SiCp composites.

On the Flexible Abrasive Tool for Nanofinishing of Complex Surfaces

Nanofinishing of complex surfaces is an important but costly processing step for many products for performing their functions satisfactorily. This paper deals with the development of a flexible abrasive tool for nanofinishing of complex surfaces. A flexible finishing tool similar to the ball end mill is developed by curing Polydimethylsiloxane (PDMS). A bowl-shaped copper workpiece is finished to nanometer surface roughness value. Different sizes of abrasive particles are used to reduce surface roughness value of the workpiece. A corrosion inhibitor is mixed with the abrasive slurry to protect the finished copper workpiece surface. A final surface roughness value of 50[Formula: see text]nm has been achieved with a variation up to 70[Formula: see text]nm on different locations of the bowl-shaped workpiece.

Microstructure characterization of W-Ni-Fe heavy alloys with optimized metallographic preparation method

Tungsten heavy alloys (WHA) have been widely adopted in many engineering applications due to their excellent physicochemical properties. Microstructure characterization is a very powerful method ranging from testing materials properties to detecting material failures and defects. However, the microstructure of WHA was not well characterized with the sample prepared by conventional method of etching with strong acids, bases or oxidant after polishing for the coarse surface. To solve the problem, the exact characterization of W-Ni-Fe heavy alloys microstructure was conducted using the sample prepared by optimized polishing method. A series of experiments were conducted to find the suitable polishing conditions including polishing pad, abrasive slurry and slurry pH. The results show that a smooth and clear microstructure sample was obtained by polishing with alkaline colloidal silica and IC polishing pad, which contained few defects compared with that obtained by conventional method of etching after polishing. The microstructure of W-Ni-Fe heavy alloys was analyzed by XRD, EDS tests and EPMA detection. The slipping phenomenon was observed in nanoindentation test using the prepared sample for the first time and the mechanism of satisfactory microstructure sample preparation was illustrated.

Interplay between toothbrush stiffness and dentifrice abrasivity on the development of non-carious cervical lesions.

This study investigated the effect of toothbrush stiffness and dentifrice slurry abrasivity on the development and progression of simulated non-carious cervical lesions (NCCLs). Human maxillary premolars were allocated to 12 groups generated by the association between toothbrushes, soft, medium, and hard stiffness, and simulated dentifrice slurries, lower, medium, and higher; deionized water (DI) served as negative control. Teeth were mounted on acrylic blocks, and their root surfaces partially covered with acrylic resin to simulate gingiva, leaving a 2-mm area apical to the cemento-enamel junction exposed to toothbrushing. Specimens were brushed with the test slurries for 35,000 and 65,000 double strokes. Impressions taken at baseline and after both brushing periods were scanned by a 3D optical profilometer. Dentin volume loss (mm3) was calculated by image subtraction. Data were analyzed using three-way ANOVA and Fisher's PLSD tests. All toothbrushes caused higher volume loss when associated to higher abrasive slurry, compared to medium- and lower-abrasive slurries. Medium caused more volume loss than lower-abrasive slurry, which led to more volume loss than DI. Hard and medium toothbrushes were not different when used with medium- or higher-abrasive slurries. There were no differences among toothbrushes when used with DI and lower-abrasive slurry. Overall, 35,000 brushing strokes resulted in significantly less volume loss than 65,000. Toothbrush stiffness was an important factor on NCCL development, especially when brushing with medium- and higher-abrasive slurries. Medium and hard toothbrushes associated with medium- and high-abrasive toothpastes can yield more severe NCCLs.