Sandblasting Research Articles

Effect of Anti-COVID-19 Mouthwashes on Shear Bond Strength of Resin-Matrix Ceramics Repaired with Resin Composite Using Universal Adhesive: An In Vitro Study

Using anti-COVID-19 mouthwashes has become necessary to reduce acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmissions. Resin-matrix ceramic (RMCs) materials that are exposed to mouthwashes may affect the bonding of repaired materials. This research was performed to assess the effects of anti-COVID-19 mouthwashes on the shear bond strengths (SBS) of RMCs repaired with resin composites. A total of 189 rectangular specimens of two different RMCs (Vita Enamic (VE) and Shofu Block HC (ShB)) were thermocycled and randomly divided into nine subgroups according to different mouthwashes (distilled water (DW), 0.2% povidone-iodine (PVP-I), and 1.5% hydrogen peroxide (HP)) and surface treatment protocols (no surface treatment, hydrofluoric acid etching (HF), and sandblasting (SB)). A repair protocol for RMCs was performed (using universal adhesives and resin composites), and the specimens were assessed using an SBS test. The failure mode was examined using a stereomicroscope. The SBS data were evaluated using a three-way ANOVA and a Tukey post hoc test. The SBS were significantly affected by the RMCs, mouthwashes, and surface treatment protocols. Both surface treatment protocols (HF and SB) for both RMCs, whether immersed in anti-COVID-19 mouthwash or not, improved the SBS. For the VE immersed in HP and PVP-I, the HF surface treatment had the highest SBS. For the ShB immersed in HP and PVP-I, the SB surface treatment had the highest SBS.

Improving epoxy adhesion with steel adherends using a tannic acid‐based additive: Impact on resin properties and interfacial bonding

AbstractTraditional adherend surface treatment techniques such as grit blasting, acid etching, phosphating and primer treatments alone are often inadequate for maintaining interfacial bond durability of adhesively bonded joints. Therefore, the existing interfacial bonds between epoxy adhesive and the adherend should be strengthened. Tannic acid (TA) is a plant‐based polyphenol that is inexpensive and easily available in nature. Its potential as an additive to improve the interfacial bond durability of epoxy adhesives has not been studied adequately. In the present study, an additive (TA‐AGE) was synthesized by grafting allyl glycidyl ether (AGE) onto phenolic hydroxyl groups of TA. With 1 wt% TA‐AGE additive in the epoxy, the single lap shear strength improved by 37%. Further, accelerated aging studies were performed to understand the impact of water uptake on the mechanical and viscoelastic properties and interfacial bond durability of the epoxy with 1 wt% TA‐AGE additive. TA‐AGE modification can increase hydrophilicity and enhance the water uptake characteristics of epoxy. This can negatively impact its mechanical properties and glass transition temperature (Tg) due to plasticization effects. Nevertheless, Boeing wedge test and single lap shear tests reveal that the strengthened interfacial bonds to steel adherends with the additive were robust and durable.

Finite Element Analysis of Damage of Cylindrical Roller Bearing of Main Shaft of Shot Blasting Machine

The main shaft of shot blasting machine mainly uses cylindrical roller bearing as the supporting part. The influence of stress, strain and temperature on bearing damage was studied by thermal structural coupling analysis of the bearing through finite element simulation. The causes and main damage forms of bearing surface were verified by super depth of field observation and finite element analysis. It is found that there exists pyramidal strain in the contact area between inner and outer raceway and roller, and its distribution form is continuous point distribution. The stress concentration is mainly distributed in the contact area between the roller face and the retaining edge, and the roller temperature is more concentrated in the area near the end face. The maximum length and depth of spalling pit on racetrack surface were 572.2μm and 14.15μm respectively. The maximum width and depth of the scratches on the roller surface are 386.7μm and 10.7μm, and the damage degree of the roller surface is not uniform. The thermo-structural coupling analysis is used to simulate the running state of bearings, which is of guiding significance to analyze the failure forms of bearings and improve the service life of bearings.

Surface characteristics enhancement and morphology evolution of selective-laser-melting (SLM) fabricated stainless steel 316L by laser polishing

Additive manufacturing (AM) metal parts often have internal defects and rough surfaces. Particularly for materials with corrosion resistance requirements, such as stainless steel 316L, the AM parts require post-treatment processes. Laser polishing is an efficient and environmentally friendly polishing technique to enhance their serviceability. Nevertheless, investigations into the evolution of surface morphology, defect formation, and surface characteristics of laser-polished AM parts are still lacking nowadays. To investigate the evolution of surface morphology and defect formation, orthogonal experiments on the laser polishing process were conducted on SS316L fabricated by selective laser melting (SLM). The influences of laser power, scanning rate, and spacing distance on surface roughness and integrity were investigated. The surface roughness Sa was reduced from 7.02 µm to 0.28 µm. The conditions for the development of porosity defects on the polished surface were analyzed. Multi-physics models were established to simulate the molten metal flow and surface morphology evolution, as well as defect formation in the cooling stage. The convergence and overflow of sub-surface defects were likely to form pores with excessive laser power. To compare the surface characteristics with the common polishing method, the potentiodynamic polarization curve, energy dispersive X-ray spectroscopy, and X-ray diffraction analysis were conducted. The corrosion resistance and surface microstructure after laser polishing and abrasive blasting were compared. The effectiveness of the optimized laser polishing process was verified, which is essential for broadening the application of AM parts.

Effects of Ti6Al4V mechanical and thermal surface modification on the adhesion of a chitosan-bioactive glass coating

Biomedical implants interact with human tissues introducing significant perturbation into the body. Implant surfaces can be then functionalized enabling better biocompatibility. At the same time, the additional use of a coating provides further functions such as corrosion protection, osteointegration, and drug delivery. In this context, a composite made of chitosan and bioactive glass nanoparticles has been used for coating Ti6Al4V alloy samples processed beforehand using different processes, i.e., polishing, milling, grit blasting, and electrical discharge machining. Experiments have been carried out to correlate substrate surface conditions and coating effectiveness in terms of scratch resistance with the final aim to obtain suitable guidelines to improve substrate-coating performances.Graphical

The effect of surface treatments of tooth on the shear bond strength of direct composite veneers: An in vitro scanning electron microscope study.

The bond strength between tooth structure and restorative materials is critical for the long-term success of dental restorations. This study sought to determine how the shear bond strength (SBS) and type of bond breakdown were affected by the inclusion of sandblasting (SB) as a conditioning step before acid etching (AE). A total of 40 extracted human molars were split into two groups at random: intervention (SB followed by AE) and control (AE only). Composite resin cylinders were constructed on the tooth surface following the application of the bonding agent. A universal testing device was used to determine the SBS, and scanning electron microscopy was used to assess the kind of bond failure. In comparison to the control group, the intervention group displayed a significantly higher SBS (P < 0.05). In contrast to the control group, which showed more adhesive failure at the tooth-resin interface, the intervention group also demonstrated a larger percentage of cohesive failure within the composite resin. As an extra conditioning step, AE after SB considerably increased the SBS between tooth structure and composite resin. The fact that the intervention group experienced a higher percentage of cohesive failure shows that this technique could boost the bond's longevity.

Potential use of Foundry sand and Furnace blast sand for fabrication of visibly active composite to promote circular economy/waste-management for treating real agro-industrial wastewater.

A two-step process of coagulation/flocculation followed by a simultaneous dual process (photocatalysis + photo-Fenton) is developed to treat real pulp and paper (P and P) industry wastewater. The rigid stout color wastewater was treated using a sunlight-responsive and cost-effective Fe-TiO2 composite using recirculating photoreactor with a total working volume of 4L. The key point of this study is that the treatment is done in very less time (90 min) and it incorporates the idea of circular economy, as the composite is fabricated out of industrial rejects. The further intensification of the process was done by proper process optimization of both approaches. With an initial concentration of stout color (0.78 AU) and COD (2200 mg/L), the optimized conditions gave a good reduction in % color and % COD i.e. 64.1% and 41.8% (1280 mg/l) after coagulation/flocculation and 89.74% and 53.12% (600 mg/l) after dual respectively. The composite was characterized by using various techniques like FESEM/EDAX, UV-vis DRS, XRD, etc. to check the catalyst composition, complexes formed between Fe-TiO2, and the catalyst intactness in both fresh and 50 times recycled composite. A trapping study was also performed using various quenchers to confirm that OH• plays a major role in the present study amongst other radicals produced where 55-60% drop in color removal was seen. In order to foresee the commercial use of this study, the process' cost was also estimated.

Ageing-resistant bonding on stainless steels by laser treatment followed by flame silicatization

In many technological areas, especially in the medical sector, stainless steel parts are being used due to their longevity, good biocompatibility, and high resistance against hygrothermal conditions related to sterilization procedures. Numerous medical products include an adhesive bond that have to reliably withstand these harsh conditions encountered, for example, during autoclaving. However, well established adherent treatment procedures require hazardous chemicals or are not suitable for small fragile parts, for example, components of endoscopes. Therefore, efficient alternatives are necessary. This publication thus presents a combined surface treatment procedure of laser ablation/structuring and flame silicatization. The investigations demonstrate that the resistance to hygrothermal ageing of stainless steel adhesive joints can be significantly increased by pulsed laser irradiation. However, a drastic improvement can only be achieved when the laser fluence exceeds a certain threshold value and, in addition, a nanoporous oxide layer with a reduced chromium content is formed. For substrates of this surface type, ageing resistance can be increased even further by subsequent flame silicatization treatment. The combined methods have proven to be superior as compared to well established processes like sand blasting and coating or corundum blasting.

Improvement of thermal plasma sprayed coating adhesion strength by laser microtexturing of aluminum

Grit blasting and laser processing are two common methods used for surface microtexturing to enhance coating adhesion strength. This paper reports a thermomechanical method of laser microtexturing of Al 7075 alloy using a nanosecond pulsed laser to generate a large increase in surface area. The entire surface area of the substrate was microtextured using laser melting, ablation, and resolidification. The laser microtextured surface morphology consisted of tightly packed pillar-like surface features. The morphology of the microtexture was varied by controlling the laser processing parameters. The laser microtextured surface was coated with metallic particles using a thermal spray process. The tensile adhesive strength of the thermally sprayed metallic coating was higher by over 17% for a 5-μm deep microtexture, compared to that of grit-blasted samples. Also, this is the highest reported adhesion strength for laser-based microtexturing methods for thermally sprayed bond coatings.

Tests on slip resistant behaviour of aluminium alloy-stainless steel faying surfaces

Aluminium alloy-stainless steel structures combine the benefits of high strength-to-weight ratios of aluminium alloys with the excellent ductility of stainless steels. In order to explore the slip resistant aluminium alloy-stainless steel connections, this paper emphasized the surface characteristics and slip resistance of various surface treatments on aluminium alloy and stainless steel plates. Six applicable treatment methods for aluminium alloy-stainless steel slip resistant faying surfaces were experimentally investigated with specifications for the key parameters explored for the treatment procedures. The feasibility of two novel surface treatment methods on aluminium alloy and stainless steel surfaces was evaluated by material tests and the inspection for coatings. The key characteristics of the treated surfaces were comprehensively tested, including the 3D scanned surface topography, measured hardness and roughness. The relationships between the material type, hardness and roughness values under various surface treatments were discussed, which suggested the specific provisions for slip resistant connections in aluminium alloy-stainless steel structures were required. Friction tests of 18 shear connections were conducted to study the friction coefficients of different materials and surface treatments. The impactions of the surface characteristics on slip resistant behaviours of the treated surfaces were analysed. The roughness of the stainless steel surfaces and the hardness of the aluminium alloy surfaces influence the friction coefficients of the examined connections. Through comparative studies, the arc spraying and supersonic cold spraying, as two novel surface treatments, are suggested for the faying surfaces of aluminium alloy-stainless steel shear connections relying on their remarkably high friction coefficients. While the grit blasting and wire brushing also presented pronounced slip resistant capacities among the four examined mechanical surface treatments.

Erosion resistance enhancement of polymeric composites with air plasma sprayed coatings

This paper addresses the fabrication and performance evaluation of a solid particle erosion resistant layer for polymer-based composites. Air plasma spray (APS) was used to deposit three different coating materials (tungsten carbide‑cobalt, martensitic chromium stainless steel, and alumina-titania) as an erosion resistant layer on top of a carbon/epoxy composite. A woven wire, stainless steel mesh was placed on top of the composite substrate during the composite fabrication process with the intention of producing a protection for composite fibers during grit blasting and thermal spraying, enabling the deposition of relatively harder materials on the composite and enhancing the adhesion strength between coatings and substrate. Desirable processing parameters for grit blasting and plasma spraying were also identified. Several tests were conducted on the coated samples to determine their mechanical and tribological performances. Using flatwise tensile tests, it was shown that the identified processing parameters could significantly improve the coating bonding strength. Solid particle resistance tests were also performed using air-jet erosion (ASTM G76) as well as hardness measurements on the coated samples. It was observed that coating materials with a brittle behavior offer a higher erosion resistance when they are sprayed on stiff and hard substrates. It was established that these coatings require strong support from the hard substrate to be more durable against erodent particles. Experimental results also indicate that coating materials with a ductile behavior are more desirable to be deposited on less stiff (soft) substrates such as carbon fiber reinforced composites.

Vibration analysis of shot wheel in abrasive blasting

Today, abrasive blasting is experiencing rapid development, due to two important factors. The first one is related to the introduction of the throwing wheel as an element that sets the granular media in motion directing them to the treated surface, while the second factor is related to the production of modern machining media. Together, these factors make blasting one of the most efficient mechanical surface preparation methods. Unfortunately, the high erosiveness of the abrasive stream, so appreciated in the process of preparing the treated surface, also contributes to significant wear of the elements in its immediate vicinity. The undertaken issues focus on the possibilities of classifying various states of the throwing wheel of a rotary machine tool based on the analysis of its dynamic properties.

Simulation of a single interaction of an abrasive particle with the surface of a part during blasting

It is shown that when modeling a single interaction of an abrasive particle with the surface of a part in the process of collision under air (liquid) pressure, it is necessary to take into account the specifics of impact-abrasive wear, when the separation of a wear particle is preceded by metal destruction. In the process of schematization of the contact interaction during abrasive blasting, some commonality with the shot blasting process and a number of assumptions typical for grinding, when micro cutting with a single abrasive grain is considered, are taken into account.

THE USE OF SUPERSONIC ELECTRIC ARC METALLIZATION TO PRODUCE CORROSION-RESISTANT COATINGS OF AGRICULTURAL MACHINERY PARTS

During seasonal work, as practice shows, the paintwork is subject to damage, which leads to the appearance of corrosion foci on steel structures, the removal of which requires considerable labor. The applied paint coatings of agricultural machinery are short-lived, therefore, the development and implementation of new progressive methods of protecting parts of agricultural machinery from corrosion is important. (Research purpose) The research purpose is to extend the service life of agricultural machinery by creating an anticorrosive coating by supersonic electric arc metallization with subsequent application of paint and varnish coating. (Materials and methods) Abrasive blasting with corundum was performed for preliminary preparation of the surface of the parts before coating by electric arc metallization. A specialized installation for electric arc supersonic metallization «Dragon» was used for coating, zinc-aluminum wire Zn85/Al15 was used as the applied material. (Results and discussion) Selected equipment for the preparation of parts and assemblies and the application of anticorrosive coating by supersonic electric arc metallization. We have completed the layout of the site for coating. The modes of supersonic electric arc metallization were established. The modes of obtaining high-quality and durable coating of products were worked out on the basis of the Kaluga Region state enterprise «Kaluga Machine-Technological Station». (Conclusions) Anticorrosive treatment of products operating in aggressive environments is most effective when two coatings are applied sequentially: anti-corrosion layer by electric arc metallization and subsequent application of a layer of paint and varnish coating. The use of the technology of abrasive blasting and anticorrosive protection of housing and frame structures of agricultural machinery by the method of supersonic electric arc metallization allows extending the service life of these structures for 12 years.

ИССЛЕДОВАНИЕ СТРУКТУРЫ СЛОЖНЫХ ПОВЕРХНОСТЕЙ ДЕТАЛЕЙ ПОСЛЕ ДРОБЕСТРУЙНОЙ ОБРАБОТКИ

The article shows that in order to determine the parameters of the surface structure, it is necessary to use optical research methods. An optoelectronic complex has been developed that allows determining the amplitude and average step of the correlation surface depending on the modes and conditions of shot blasting. A measurement technique and a software package for determining the parameters of the surface structure are proposed. The identification of structural parameters with the roughness parameters of complex surfaces was carried out.

On relationship of processing operating parameters of during shot-impact hardening of machine parts

The article presents the materials for the analytical determination of the flight speed of the shot during pneumatic shot blasting, when the main regime parameter is the pressure of compressed air, which makes it possible to interrelate the technological parameters in the shot hardening of machine parts and reasonably evaluate the state of the surface layer through the energy criterion.

Abrasive blasting of the teeth of linter saws with the aim of their activation

The article presents materials on the effective use of abrasive blasting of the side surfaces of the teeth of saw blades in order to activate them during lightering. The scraping action and cutting of short fibers from seeds is enhanced by microroughnesses of the formed micro profile after impact interaction of an abrasive particle with a metal surface. Using atomic force microscopy, we obtained the height and step parameters of the roughness of the machined tooth surface, which are compared with the transverse dimensions of the cotton fibers, and thus a model for the intensification of the littering process is proposed.

Parametric Characterization of Machined Textured Surfaces

Surface topography in general is not easy to characterize due to a great number of different features that appear on it. It is still more challenging for machined textured surfaces that are of high functional significance for tribological purposes. For practical reasons, there is a need to describe such surfaces using only a small number of parameters. Which of them represent surface details the best is still an open issue. To find out which parameters can be the most suitable in that case, three groups of machined textured surfaces were prepared. They were plateau-honed cylinder surfaces made of gray cast iron, steel, and bronze surfaces with isolated dimples and steel surfaces after abrasive blasting followed by lapping. All of them were measured by means of a white light interferometer. Different parameters and relationships were evaluated and based on them correlation and regression analyses were used. The basic description contained statistically independent parameters that can be used in production control, while the wider description in scientific research. In general, parameters of random surfaces were more intercorrelated than those of surfaces with isolated dimples. As was found for the basic description of random two-process surfaces, five parameters were enough while description of textured surfaces with isolated oil pockets needed six. In wider, scientific description, regardless the surface type seven parameters contained the necessary information about the surface. It was also proved that a pair of parameters, the emptiness coefficient Sp/Sz and Sq/Sa, can describe the shape of the ordinate distribution of machined textured surfaces better than, for example, skewness Ssk and kurtosis Sku, commonly used for that purpose.

Effects of different frequencies of Er:YAG laser on the bonding properties of zirconia ceramic.

The effects of Er:YAG laser with different frequencies on zirconia ceramic's bonding properties were studied. In total, 42 Y-TZP (yttrium-stabilized tetragonal zirconia polycrystals, UPCERA ST) with 3mm × 3mm × 2mm divided into 6 groups (n = 7): control (C), sandblasting (SB), and Er:YAG laser (A1-A4), which the frequencies correspond to 5Hz, 10Hz, 15Hz, and 20Hz, IPS e.max Press ceramics were B. Scanning electron microscope (SEM) images were recorded. The ceramics were bonded to enamel from extracted teeth. After being constantly stored at 37 ℃ for 24h, the shear test was performed with a universal testing machine. Stereomicroscope evaluated fracture modes. Stereomicroscope evaluated fracture modes. Data were analyzed by SPSS26.0 statistical software; the standard was P = 0.05. (1) The SEM showed the surface of A1-A4 became rough compared with C. (2) The shear test showed that the highest bonding strength for B was 13.15 ± 2.97MPa, followed by SB was 7.78 ± 0.97MPa, and A2 was 7.13 ± 0.75MPa. However, there was no significant difference between SB and A2 (P > 0.05). Fracture modes of C were the interface fracture of Y-TZP and resin adhesive; most of A1-A4 and SB also were interface fracture, a few mixed fractures, and cohesion fracture of resin adhesive; B were all mixed fracture. Er:YAG laser with 10Hz could be used as an alternative to sandblasting with Al2O3 for surface modification of Y-TZP to increase the bonding strength.

Repair Bond Strength of Conventionally and Digitally Fabricated Denture Base Resins to Auto-Polymerized Acrylic Resin: Surface Treatment Effects In Vitro.

Denture base fracture is one of the most annoying problems for both prosthodontists and patients. Denture repair is considered to be an appropriate solution rather than fabricating a new denture. Digital denture fabrication is widely spreading nowadays. However, the repair strength of CAD-CAM milled and 3D-printed resins is lacking. This study aimed to evaluate the effect of surface treatment on the shear bond strength (SBS) of conventionally and digitally fabricated denture base resins. One l heat-polymerized (Major base20), two milled (IvoCad, AvaDent), and three 3D-printed (ASIGA, NextDent, FormLabs) denture base resins were used to fabricate 10 × 10 × 3.3 acrylic specimens (N = 180, 30/resin, n = 10). Specimens were divided into three groups according to surface treatment; no treatment (control), monomer application (MMA), or sandblasting (SB) surface treatments were performed. Repair resin was bonded to the resin surface followed by thermocycling (5000 cycles). SBS was tested using a universal testing machine where a load was applied at the resin interface (0.5 mm/min). Data were collected and analyzed using ANOVA and a post hoc Tukey test (α = 0.05). SEM was used for failure type and topography of fractured surfaces analysis. The heat-polymerized and CAD-CAM milled groups showed close SBS values without significance (p > 0.05), while the 3D-printed resin groups showed a significant decrease in SBS (p < 0.0001). SBS increased significantly with monomer application (p < 0.0001) except for the ASIGA and NextDent groups, which showed no significant difference compared to the control groups (p > 0.05). All materials with SB surface treatment showed a significant increase in SBS when compared with the controls and MMA application (p < 0.0001). Adhesive failure type was observed in the control groups, which dramatically changed to cohesive or mixed in groups with surface treatment. The SBS of 3D-printed resin was decreased when compared with the conventional and CAD-CAM milled resin. Regardless of the material type, SB and MMA applications increased the SBS of the repaired resin and SB showed high performance.