Abrasive Powder Research Articles

Fabrication of a new core–shell structured magnetic abrasive particles with good performance

The traditional Fe-based magnetic abrasive powders (MAPs) are prone to degrade by corrosion and oxidation. The extremely low stability to some extent limits the development of magnetic finishing. In this study, a new kind of 410 stainless steel-based spherical MAPs with core–shell structure was synthesized by gas nitriding. The nitride layer shows the dendrite structure containing (Fe, Cr)4N phase and lath-like CrN phase. The Zirconium tube roughness can be reduced from 0.280 to 0.153 μm. The origin of the good finishing performance was investigated through the Vickers hardness and nanoindentation tests.

In vitro evaluation of surface roughness of titanium abutments after air polishing with different abrasive powders

AbstractObjectivesThe purpose of this study was to evaluate the effects of air polishing with sodium bicarbonate and erythritol powders on surface roughness and morphological changes in titanium abutments.MethodsA total of 45 grade V titanium discs were divided in three groups: Group A (Control) air polished with air/water; Group B, air polished with sodium bicarbonate powder; and Group C, air polished with erythritol powder. After air polishing, the samples' roughness (Sa) in micrometres were analysed with an optical profilometer. The samples' surface morphology study was conducted via scanning electronic microscope (SEM). Data were described using mean and standard deviation of roughness values (Sa). Inferential analysis was performed using the ANOVA multiple comparison test followed by Tukey's post hoc test. Both tests used a 5% level of significance.ResultsAfter air polishing, average roughness of group A, B and C were 0.036, 0.046 and 0.037 μm, respectively, with statistically significant differences between groups A and B (p < 0.05). No statistically significant differences were found between group A and group C, as well as between group B and C (p > 0.05). As for the morphology analysis, damages to the titanium surface were only observed in group B.ConclusionsThe study indicates that air polishing with erythritol powder maintains titanium abutment integrity better than sodium bicarbonate, which increased surface roughness and caused damage. Erythritol is preferable for minimizing surface alterations and maintaining morphological stability.

Achieving in-situ Fe-based spherical particles for magnetic abrasive finishing process of Zirconium tube via gas nitriding method

The magnetic abrasive powders have great influence on the magnetic abrasive finishing accuracy and efficiency. A new kind of Fe-based spherical magnetic abrasive particles with Fe2N precipitates and Fe4N matrix was successfully synthesized by gas nitriding. The results show that the prepared Fe-based magnetic abrasive particles can reduce the roughness of the Zirconium tube from 0.325 to 0.154 μm by four MAF passes. The high hardness and wear resistance of the Fe-based magnetic abrasive particles are assessed based on the Vickers hardness and nanoindentation results. This study can provide theoretical and experimental support for fabricating high-performance magnetic abrasive particles.

TBL38 atypical homogalacturonan-acetylesterase activity and cell wall microdomain localization in Arabidopsis seed mucilage secretory cells

Plant cell walls constitute complex polysaccharidic/proteinaceous networks whose biosynthesis and dynamics implicate several cell compartments. The synthesis and remodeling of homogalacturonan pectins involve Golgi-localized methylation/acetylation and subsequent cell wall-localized demethylation/deacetylation. So far, TRICHOME BIREFRINGENCE-LIKE (TBL) family members have been described as Golgi-localized acetyltransferases targeting diverse hemicelluloses or pectins. Using seed mucilage secretory cells (MSCs) from Arabidopsis thaliana, we demonstrate the atypical localization of TBL38 restricted to a cell wall microdomain. A tbl38 mutant displays an intriguing homogalacturonan immunological phenotype in this cell wall microdomain and in an MSC surface-enriched abrasion powder. Mass spectrometry oligosaccharide profiling of this fraction reveals an increased homogalacturonan acetylation phenotype. Finally, TBL38 displays pectin acetylesterase activity invitro. These results indicate that TBL38 is an atypical cell wall-localized TBL that displays a homogalacturonan acetylesterase activity rather than a Golgi-localized acetyltransferase activity as observed in previously studied TBLs. TBL38 function during seed development is discussed.

Modeling of material removal by magnetic abrasive finishing of the inner wall of Co-Cr alloy cardiovascular stent tube with diamond magnetic abrasive powder prepared by plasma melting

Modeling of material removal by magnetic abrasive finishing of the inner wall of Co-Cr alloy cardiovascular stent tube with diamond magnetic abrasive powder prepared by plasma melting

Удосконалення механізму притирання вільним абразивом за допомогою використання силікатного складу

The results of an experimental study are presented that explain and confirm the mechanism of lapping friction surfaces with a silicate abrasive composition.
 It is shown that the stability of the silicate lapping paste over time can be achieved by introducing ferric trichloride (FeCl3), which in this case is a thickener of liquid glass and also has high hygroscopic properties. The adhesive properties of the silicate paste are improved by the addition of lubricant 1-13. This grease was chosen due to its water solubility. To increase the abrasive ability of the silicate paste, an abrasive powder was introduced. 
 It was found that the lapping performance of the silicate composition and the quality of surfaces are higher than when treated with the «KT» paste, which is currently used for lapping automobile engine valves. Based on the results of the study, the mechanism of lapping friction surfaces with a silicate paste is presented. The mutual movement of the surfaces results in cutting and scratching of the highest peaks of the bumps by the abrasive grains. When silicon oxide (SiO2) is added to the abrasive material, its particles are coated with silicon oxide. This is because liquid glass solutions have a high adhesive force and low surface tension. At the points of contact between the abrasive particles, the temperature rises, and since there is SiO2 around the abrasive, when the latter enters the contact zone, amorphous silica (SiO2) is formed. Since the abrasive grains are coated with a silicon oxide film, SiO2 penetrates into the cavities of micro-irregularities and adheres to the surface under repeated exposure to the abrasive. Thus, the surface to be treated is saturated with silicon oxide, which leads to an increase in its quality after grinding with a silicate composition.
 It has been proven that high surface quality is formed by amorphous silica. To confirm this mechanism, chemical and X-ray spectral analyses of the samples were performed, which showed the presence of SiO2 on the treated surface and a "strong bond" of silicon compounds with the metal surface layer. 
 It was found that the high quality of the surface is also due to the shape of abrasive particles and wear products. It has been confirmed that with the variable movement of surfaces relative to each other, abrasive grains take on a new position each time. At the same time, they are worn from all sides and acquire a rounded shape, and are simultaneously enveloped by a SiO2 foil.

Research on grinding force modelling of spherical alumina magnetic abrasive powder

Research on grinding force modelling of spherical alumina magnetic abrasive powder

Dentifrices. Part 1: a general introduction

This comprehensive review traces the evolution of dentifrices from ancient concoctions to modern formulations, evaluating their role in oral health and environmental impact. Despite the global burden of oral diseases, notably dental caries and periodontitis, advancements in dentifrice technology have contributed to the decline in caries prevalence, although periodontitis remains a challenge. The historical perspective outlines the transition from abrasive powders to fluoride-enriched pastes, emphasizing the significance of toothbrushing frequency and technique, alongside the use of dentifrices, for effective plaque control and caries prevention. The modern era has seen a proliferation of dentifrice variations, with a focus on cosmetic attributes often overshadowing therapeutic benefits. The review also discusses the environmental considerations of dentifrice production and disposal, highlighting the shift towards sustainable packaging and ingredient transparency. The market analysis reveals a mature industry with a projected growth, influenced by consumer preferences and oral hygiene awareness. CPD/Clinical Relevance: Regular toothbrushing with fluoridated dentifrice remains a cornerstone of oral hygiene practices, directly influencing the reduction of plaque accumulation and the incidence of caries and periodontitis.

ПОВЫШЕНИЕ ДОЛГОВЕЧНОСТИ ПОДШИПНИКОВЫХ УЗЛОВ СОВЕРШЕНСТВОВАНИЕМ СМАЗОЧНОЙ СРЕДЫ

We considered the issue of increasing the operational life of ball and roller bearings. Having studied the known tribomaterials to increase the resource of worn friction joints in terms of efficiency, environmental friendliness, low cost, ease of preparation and application, it was found that the introduction of friction surface geomodifiers from a mixture of serpentines, highly dispersed powders of layered hydrosilicates Mg, Al, Ni, Fe into their oils and lubricants, provides a sufficiently effective increase in the life of rolling bearings during maintenance machine and tractor park in the agro-industrial complex. (Research purpose) The research purpose is identifying the least abrasive geomodifier powder from five samples of different deposits and its optimal concentration in Litol-24 grease. (Materials and methods) Conducted standard tests of the roller-by-roller tribocouple for abrasive wear spots of bearing rollers. They were injected into Litol-24 grease in the same concentration. An assessment of the abrasiveness of powders by excision of wear spots was carried out visually and with photography on microscopes. Tribo-tests were performed with the least abrasive powder at a powder concentration in the range of 0.5-3.0 percent. The optimal concentration of the powder was revealed by the size of the wear spot areas, friction moments, and temperatures in the contact of the rollers. (Results and discussion) It was found that the least abrasive powder was N4. When its concentration in the lubricant was up to 0.5 percent, the tribological indicators corresponded to the base lubricant, with an increase in concentration to 1.0 percent, the friction moment and the wear spot decreased while maintaining the temperature in contact. With an increase in concentration to 1.5 percent, mechanical losses increased with a slight increase in wear, at concentrations of 2.5-3.0 percent, the temperature increased from 111 to 133.4 degrees Celsius, which negatively affects bearings and lubrication. (Conclusions) It was found that the optimal concentration of powder N4 in Litol-24 grease should be 1.0-1.5 percent.

Удосконалення засобів для повітряно- абразивної обробки у порожнині рота (Огляд літератури)

The purpose of the study is to analyze the content of sources of scientific and medical information related to the development and implementation of air-abrasive processing in dental practice. Materials and methods: an information search was performed in the available electronic databases of scientific and medical information using the relevant keywords «abrasive», «air-abrasive processing», «air-flow», «air-blasting» in the systems «PubMed», «Scopus ” and “Web of Science”. The search depth was 10 years, including secondary sources of information. Results. During the last two decades, air-abrasive treatment in the oral cavity has become almost a standard for professional oral hygiene in dental healthcare institutions in Ukraine. At the time of its creation, this technology involved the use of sodium bicarbonate (soda) powder, which was available in dental practice. In the course of defining the basics of the technology, Robert Black formulated the basic requirements for abrasive materials used in practice. In the absence of accepted manufacturing standards and indicators of such products, the general consensus is a list of requirements for powders for air-abrasive processing: safe removal of dental layers without damage to the enamel surface, no trauma to soft tissues and other structures of the tooth, not to linger in the oral cavity after processing, absence of reaction of a foreign body in case of accidental short-term retention in the patient’s body. Variable influencing factors when performing air-abrasive processing in dentistry remain particle size, pressure in the tip, distance to the treated surface, angle between the surface and the jet, processing time and cutting speed of the jet. The most common substances used as an abrasive component in air-abrasive processing are sodium bicarbonate, calcium carbonate, glycine, and erythritol. Conclusions. Currently, research is ongoing for clinical standardization and development of protocols for air-abrasive treatment in dentistry, improvement of abrasive powder manufacturing technology, and introduction into practice of new substances with high cleaning properties and a minimally invasive effect on tissues and surfaces in the oral cavity. Key words: dentistry, air-abrasive processing, oral cavity, periodontium, soda, calcium carbonate, glycine, erythritol.

Analysis on mechanism of material removal rate and surface flow machining process

A novel finishing technique called abrasive flow machining (AFM) uses abrasive particles as the instrument for material removal. The term "self-deformable stone" refers to the abrasive particle-containing carrier medium, and AFM is commonly known as "no-tool" precision finishing procedure. AFM involves passing a semi-solid polymer-based medium through the work piece at a specific pressure while adding abrasive particles in a specific amount. The three main parts of the AFM are the machine, the medium, and the tooling or fixture. The machine is made up of a media cylinder, hydraulic cylinder, control system, and frame structure. A typical AFM method uses extrusion pressures ranging from 15 bars to 110–210 bars. Tooling and fixtures serve the purpose of positioning the workpiece and giving instructions to the media as they go over the finished product. A carrier, some additives, and an abrasive powder make up the medium. Since the finite volume approach deals with fluid flow, it can be used to represent the flow of media. For the modelling and simulation in this work, the ANSYS 15 software package's FLUID FLOW FLUENT was utilised. Together with the fixtures, 2D model of a cylindrical workpiece and 3D model of 4 rotating dies have been created. Using the available experimental data, the two models have been validated. For varying volume fractions and media speeds, the most influential flow output characteristics, such as velocity, strain rate, and dynamic pressure have all been examined. The granular and non-granular flows were both simulated using the 3D model. The impact of various abrasive particles with varying volume fraction and diameter on the Skin friction coefficient and granular pressure, two flow output characteristics that have been researched. The outputs' flow analysis provides a forecast for the effectiveness of material removal.

ANALYSIS OF THE STRUCTURE OF INDUSTRIAL WASTE USED TO CREATE NEW COMPOSITE MATERIALS

During the production of silicon, a significant amount of waste is generated, namely micro- and nanosilica. Micro- and nanosilica, with its properties and structure, immediately interested scientists in many countries from the point of view of processing this material into a new product with unique functional properties. The article presents the results of studies of waste from various industries - microsilica, as a waste of silicon production, zinc ash - a waste of the hot-dip galvanizing process, and abrasive powder - a waste of metal machining. To study waste from various industries, the authors used the method of electron microscopy as the simplest and fastest way to transmit information about the microstructure, elemental composition and grain size distribution. A comparative analysis of the microstructures and properties of these materials was carried out in order to better understand the nature and predict the possibility of their further use as initial components for the production of new composite materials. Keywords: microsilica, zinc ash, microstructure, waste disposal, composite material, properties of new materials.

Abrasion resistance of a carbon fiber reinforced composite based on a nanoclay epoxy nanocomposite matrix

AbstractIn this paper, the abrasion resistance of a carbon fiber composite based on epoxy nanocomposite matrix filled with layered‐silicate clay nanoparticles was evaluated. In the first step of the work, the clay‐epoxy nanocomposite was first studied to assess the dispersion and the performance, and then to select the best content for the fiber composite production. The nanocomposite mixture was prepared by finely dispersing clay nanoparticles into the epoxy monomer through mechanical stirring, then the hardener was added. After this step, the fiber reinforced composite was produced by vacuum infusion, and then the properties were evaluated. The abrasion resistance has been assessed using different approaches. A test was specifically designed to simulate the impact of abrasive powders which could potentially be found in the atmosphere and crash into aircraft or air vehicles (such as for instance volcanic ashes). The results showed that the presence of nanoclay reduces the weight loss of the sample with the impacted surface, which can be clearly correlated to a damage reduction.Highlights Sandblasting tool made to mimic impact of abrasive powder on composite surface Presence of nanoclay does not significantly affect the vacuum infusion process Layered‐silicate nanoparticles lead to improve composites abrasion resistance

Effect of Surface Textures and Fabrication Methods on Shear Bond Strength Between Titanium Framework and Auto-Polymerizing Acrylic Repair Resin.

The aim of the study was to evaluate the effect of airborne particle abrasion (using different sizes of alumina particles) on the shear bond strength (SBS) between cast and milled titanium metal frameworks and auto-polymerizing acrylic repair resin. Forty flat cylindrical titanium disks were divided into two main divisions: cast and milled titanium. The two divisions were further subdivided into four groups based on metal surface treatment. Three particle sizes of aluminum oxide air abrasive powders (50µm, 110µm, and 250µm) were used for metal surface treatment by airborne particle abrasion. One group was the control group with no surface treatment. Auto-polymerizing acrylic repair resin was applied to all titanium disks. The specimens were subjected to SBS testing using a universal testing machine (Instron Corporation, Norwood, Massachusetts, United States). Surface evaluation was performed using a scanning electron microscope. One-way ANOVA was used for statistical analysis. The results showed a significant increase in SBS after airborne particle abrasion of both milled and cast titanium groups (p<0.001). The SBS was directly proportional to the size of the aluminum oxide particles. The milled titanium group showed higher SBS values than the cast group when the surface was not treated with alumina particles (p < 0.001) and when the surface was treated with the smaller particle sizes of 50 µm, whereas the cast group demonstrated higher SBS values than the milled group (p < 0.01) when the particle size was increased to 110 µm and 250 µm. It could be concluded that SBS between titanium metal frameworks and auto-polymerizing repair acrylic resin was directly related to the size of the alumina airborne particle abrasives. The fabrication method of the titanium frameworkalso influenced the SBS as the untreated milled frameworks demonstrated favorable SBS values compared to the untreated cast frameworks.

INVESTIGATION OF SURFACE ROUGHNESS IN MODERN FINISHING PROCESS USING PERMANENT MAGNET

This work introduces an investigation of the surface roughness (Ra) during flat plate machining utilizing magnetic abrasive finishing process (MAF). In this study three parameters (Machining time, Mesh size, and Gap) were studied. The MAF tool is made from permanent magnet and the abrasive powder is consisting of 40% of SiC and 60% Fe powder with three Mesh size (100, 250, and 400 µm). The Taguchi L9 array was used in designing the experiments. The results show that the increasing machining time caused a decrease in Ra. The increase in mesh size and the gap will increase the surface roughness. The dominant factor that affect the surface roughness was the machining time due to enough time to machine the target surface.

Synthesis and characterization of environment-friendly spherical cubic boron nitride magnetic abrasives by plasma molten metal powders bonding with hard materials

In this investigation, globular cubic boron nitride magnetic abrasive powders (cBN-MAPs) were synthesized with additive-free via plasma molten metal powders bonding with hard materials (PM2BH) for finishing hard and brittle materials. Experiments were carried out with cBN powder flow rates of 60–300 g/min, which significantly affected the performance and microstructure of the composites. It illustrates that: the composites are composed of cBN and α-Fe; the cBN is not transformed into hBN, which can be reused; a linear increase in the amount of cBN grains bound to the apparent layer of the ferrous substrate with increasing powder flow rate, the proportion of MAPs in the 180–230 μm size distribution and the magnetic permeability decrease; when the powder flow rate is maximum, the powder embedded in ferrous substrate completely covers the surface of the matrix, forming spherical MAPs, after 50 min of machining, surface finish of AlN ceramics improved from 342 nm to 93.5 nm, with cBN-MAPs showing normal wear within 80 min. A novel, highly efficient strategy for additive-free cBN/Fe composites is presented in this paper.

Calculation and investigation of the phase composition of a composite intermetallic layer synthesized on the surface of VT6 titanium alloy from Cu–SiC and Al–SiC powders

The physical and chemical foundations of the technology of cold gas-dynamic spraying of coatings on titanium for two types of charge are considered, in one of which chemically inactive copper is used as a ductile metal in combination with abrasive silicon carbide powder, in the other – chemically active aluminum in combined with silicon carbide. A thermodynamic modeling technique has been developed to select the composition of the coating charge and predict the change in its phase composition at high temperature.

Waste-free processing of waste nickel slags

The paper considers one of possible options for the waste-free processing of dumped masses of nickel slags, accumulated over the years of operation of some enterprises. This process includes the use of hydroand pyrometallurgical processing, which results in three products: iron sulfate, ferrosilicon with a small admixture of aluminum, and slag from the ferrosilicon smelting. The slag has a hardness of 7-7.5 Mohs and can be used as an abrasive powder for sandblasting, or as a raw material for production of high alumina cement. The resulting iron sulfate can subsequently be purified from the copper, nickel, magnesium, and aluminum impurities and brought to the existing GOST compositional requirements. The resulting ferrosilicon, whose silicon content is similar to that of the marked ferrosilicon FS 75 with an aluminum admixture, can be used for deoxidation and silicon alloying of all existing grades of steels and cast irons. In this case, specifications drawn up with participation of a consumer enterprise can be a regulatory document for such ferrosilicon. The slag obtained during the ferrosilicon smelting can also be defined within the framework of these specifications for the abrasive powder producing enterprises.

Thermal, chemical and mechanical characterization of recycled corundum powder in metakaolin-based geopolymer binder

In this study we report on the addition of a waste, a real spent corundum abrasive powder collected after testing, to a metakaolin-based alkali activated binder. The waste has been chosen as representative of spent grits produced by industrial blasting processes. In this model system based on metakaolin, the effect of corundum powder in the environment of high alkaline media was investigated in terms of 3D reticulation of the aluminosilicate amorphous structure of the consolidated geopolymeric mixes. A number of microstructural techniques (FT-IR, XRD, TGA/DTA) have been used in combination with less conventional one, such as the ionic conductivity measurements of the eluate produced after 24 h of immersion of the sample in water. The overall 3D aluminosilicate frame typical of MK-based geopolymer is retained also after 50 wt% addition of recycled corundum, as shown by FT-IR, XRD, and TGA/DTA. The traces of ceramic materials abrasion present in the waste showed good reactivity, as shown by the disappearance of their characteristic peaks in the XRD patterns. Ionic conductivity of the eluates evidenced the most extended reactivity of the alkaline activator solution in the case of 10 and 20 wt% addition of the waste. While the role of 20, 30 and 40 wt% addition of the waste to the MK-based matrix produced the highest compressive strength in the consolidated mortars after 28 days comparable to those of Ordinary Portland cement concretes. It was proved that, when produced using a partially reactive waste with well-formulated mix designs, metakaolin alkali-activated binders or mortars are an important aluminosilicate source for room temperature produced construction materials.

Numerical modeling of the erosion of alumina particulate reinforced epoxy-matrix composites: Material removal mechanisms including reinforcement fracture

Sacrificial composite coating layers are used to protect surfaces from solid particle erosion due to the high-speed impact of particles. Epoxy-based coatings are easily reapplied and are sometimes mixed together with a reinforcing phase consisting of ceramic particles in an attempt to lower the erosion rate. Previous experiments have indicated that different erosion mechanisms can occur depending on, amongst other things, the relative sizes of the reinforcement and abrasive particles. In the present work, a coupled finite element/smoothed particle hydrodynamics (FE/SPH) decomposition method was used to model the erosion of an epoxy-matrix composite reinforced with relatively large 0.5 mm alumina (Al2O3) spheres, by irregularly shaped 152 μm silicon carbide (SiC) abrasives. 5600 overlapping impacts of SiC particles were modeled on carefully chosen representative volumes of the particulate reinforced composite. A Johnson–Holmquist material model (JH-2) with dynamic tensile strength was used to model the particulate phase, while the epoxy was modeled using a piecewise linear plasticity material model coupled with a Cowper-Symonds strain and strain rate hardening relationship. Realistic abrasive particle morphologies were modeled, based on measurements of the abrasive powder used in the verifying experiments. The erosion rates at both perpendicular and oblique incidence were successfully predicted to within ∼10% of those measured. Both the model and experiments showed that the erosion resistance of the composite was higher than the epoxy at oblique incidence; however, at perpendicular incidence, even though the erosion rate of the reinforcements (0.67 ± 0.04 mm3/g) was lower than that of the epoxy (1.27 ± 0.1 mm3/g), the erosion rate of the composite was slightly higher (∼1.38 ± 0.16 mm3/g) than that of the epoxy. It was shown that this occurred because, as the epoxy eroded in a typically ductile fashion with cutting and ploughing mechanisms, the reinforcements fractured leading to an approximately level eroded surface at any instant. The model was able to capture these material removal mechanisms which were also confirmed using non-contact profilometry of the eroded surfaces.