Papers by Keyword: Surface Treatment

Abstract: Adhesive bonding is increasingly used in lightweight structural applications, though its effectiveness for carbon fiber reinforced polymers is often limited by low surface energy. This study investigates the concurrent effect of infrared laser surface texturing and resin pre-coating on the mechanical performance of carbon fiber-reinforced polymer single-lap joints. Using a CO₂ laser system, micro-dimples were generated on the substrate to promote mechanical interlocking, while various concentrations of an epoxy resin (5 wt%, 10 wt%, and 20 wt%) were applied as precoating to enhance surface wetting and interfacial continuity. To validate the experimental findings, a numerical investigation was performed using a Cohesive Zone Model implemented within a finite element framework. This model utilized a bilinear traction-separation law and a quadratic delamination criterion to predict the progressive debonding and failure of the interface. Experimental results indicate that the 10 wt% resin pre-coating concentration provides the highest lap shear strength.

Abstract: PEEK is a thermoplastic polymer widely employed in the orthopedic field for the fabrication of prosthetic devices, owing to its Young’s modulus being comparable to that of cortical human bone. Surface functionalization through biomaterial micropatterning represents an effective strategy to enhance osteointegration. To this end, an innovative vibration-assisted surface embossing process was applied to PEEK samples. The surface patterning was performed using a square punch with a side length of 0.5 [mm], fabricated via CNC milling. The process is enabled by a linear actuator capable of generating controlled vibrations to induce localized sub-Tg heating of the polymer surface. After that, the application of a post-load is required for the embossing stage. This system allows frequency tuning in the range of 1–4 [kHz]. Finally, the patterned surfaces were sonicated through an ultrasound cleaner and characterized through contact angle measurements and white-light interferometry, confirming the feasibility of the process and demonstrating an increase in both the polar component of the surface free energy and the hydrophilicity compared with merely polished specimens. Enhancing the polar component of surface free energy is an effective strategy to improve biomaterial biocompatibility, confirming the relevance of the proposed surface modifications. Slightly hydrophilic surfaces promote preferential osteoblast adhesion and stable cytoskeletal organization, demonstrating the complementary roles of surface topography in shaping cellular responses.

Abstract: This study systematically evaluated nine surface treatment conditions on titanium dental implant fixtures, combining Sandblasted Large Grit Acid-etched (SLA) with anodizing methods. A total of 112 samples were characterized using FESEM, EDAX, MTT, wettability, surface energy, and osseointegration analyses. Among the tested protocols, the SLA+Anodizing process with the following parameters proved most effective: sandblasting with 75 µm particles at 4 bar and 30° angle, acid etching at 75°C for 6 minutes, and anodizing at 100 V for 5 minutes. This optimized surface demonstrated superior outcomes, including 97% cell viability, enhanced osseointegration within twelve days, and a chemical composition consistent with Grade 5 titanium alloy (Ti-6Al-4V), typically comprising approximately 90% Ti, 6% Al, 4% V, and trace amounts of O, Fe, and other elements.

Abstract: This study investigates the effect of different joint designs and surface treatments on the flexural strength of a 3D-printed resin denture base. Seventy specimens of 3D-printed resin were used in this study, these specimens were grouped according to the joint design into four groups (positive control group, butt-joint group, bevel-joint group, and round-joint group) except the positive control group each one of these groups is subgroup into another three groups according to the surface treatment material into heat-cured monomer (MMA), sandblast, and 3-D printed resin. The specimens were cut in the middle according to the joint shape, and the cut surfaces were treated with heat-cured MMA monomer, sandblast, and 3D-printed resin (as a negative control group). Then a silicone mold was used to prepare the specimens with 3D printed resin, using a light-emitting diode, and post-cured with a light-cured unit box. An Instron testing machine examines all specimens. The bevel-joint group repaired with 3D printed resin (G7) had the highest mean flexural strength (85.0483) MPa and a significant difference from the control group. For fixing a fractured denture base made of 3D-printed resin, the bevel-joint design is the most recommended design of the joint, and the best material for treatment is 3D-printed resin. Then a round-joint with heat-cured monomer and the butt-joint with 3D-printed resin treatment.

Abstract: The research presented results on improving the properties of hempcrete and hemp concrete by pretreating the hemp surface using aluminum sulfate with 3 other additives including plasticizers, natural rubber latex, and polymer. The aim of the research was to investigate the changes in the compressive strength of the blocks. Hempcrete samples were produced with a ratio by weight of hemp to lime of 1:12 and a water content of 34.62% by weight. Hemp concrete samples had a ratio of hemp:hydraulic cement:soil of 1:4:8 and a water content of 34.62% by weight. Both samples were formed using a 7.5 x 30 x 10 cm steel mold. Results from the compressive strength test found that the strength for both hempcrete and hemp concrete improved using 10% by weight aluminum sulfate together with polymer had the highest increase in strength in comparison to the other cases in this study. The compressive strength obtained was 1.21 MPa for hempcrete and 2.83 MPa for hemp concrete, resulting in an increase of 55.13% and 194.79%, respectively. These results showed that this method for improving the properties of hemp concrete made its compressive strength higher than the standard for nonloadbearing concrete masonry as required by construction standards.

Abstract: Concrete, a fundamental material in modern construction, is prone to water penetration, which can lead to structural degradation. Conventional waterproofing methods often rely on materials with significant environmental impacts. This study explores the use of wood tar (WT), derived from Eucalyptus wood pyrolysis, as a sustainable waterproofing agent for concrete. The WT was characterized using pH and thermogravimetric analysis (TGA), as well as gas chromatography-mass spectrometry (GC/MS). With a small modification, the WT waterproofing efficacy was tested through contact angle measurements and water absorption by capillary rise within concrete. Results indicated that WT-coated concrete exhibited significantly lower water absorption and demonstrated potential as an eco-friendly alternative to traditional waterproofing methods. Although preliminary results, this research contributes to the development of sustainable building materials, driving innovation to construction practices.

Abstract: This study aims to evaluate the functionality and effectiveness of a new tool for ironing 3D printed components using FDM technology. The ironing process draws inspiration from the ball burnishing process, employing a spherical tool that, by exerting pressure, modifies the component's surface. The process involves heat transfer between the tool and the component to soften and deform the surface more easily. A theoretical analysis of the resulting surface roughness following this process was conducted to identify the parameters at play and their influence. It was found that the two main parameters are the fillet radius and the distance between passes. Additionally, practical tests were carried out to confirm the hypotheses, revealing the influence of three other parameters: tool Z-axis positioning, temperature, and movement speed. The surface after treatment exhibits an average roughness of Ra = 0.378 μm, significantly better than values obtained with ironing performed with the nozzle and with quality comparable to grinding. This lays the groundwork for possible future optimization of parameters based on the component's characteristics and the material used.

Abstract: The paper presents and discusses the durability parameters of concrete (total water absorption, capillary absorption, and compressive strength), which have been monitored over a long-term period of 3 years. The concretes were prepared with recycled brick aggregate of fraction 4/8, the latter being surface treated by different procedures before mixing the concrete. Surface treatments allow the RBA to achieve a lower water absorption capacity (45-82% decrease), thus gaining a potential to optimize the amount of mixing water, and thus improve the quality of the concrete. After 3 years of curing, all samples still show better property values than the initial values at 28 days, indicating good durability over this period.

Abstract: The present paper aimed at investigating the influence of surface treatment on the failure of porcelain coating on Ti6Al4V alloy fabricated by milling and selective laser melting (SLM). The titanium alloy surface was treated by three different ways: sandblasting, application of a layer of bonding agent and combined (sandblasting and subsequent bond layer). A coating of ultra-low fusing ceramic was fabricated on one surface of the samples. The adhesion of the porcelain to the titanium alloy was investigated by standard 3-point bending test and the failure of the coating was evaluated by optical microscopy. It was found that the type of surface treatment of the titanium alloy affects the failure mechanism of porcelain coating on its surface. In case of all samples, the fracture of the ceramics was observed to occur by a mixed adhesion-cohesion mechanism with a difference in the layer of adhesive or cohesive failures. These differences are greater for the milled alloy compared to its SLM-treated counterpart. In the milled sample, adhesive failure occurs along the metal/oxide layer interface and cohesion through the oxide layer. After sandblasting, both adhesion and cohesion fractures were observed between the oxide layer and the porcelain. In the bond-treated samples, adhesive and cohesive failures were found to occur mainly between the oxide layer and the bond. Most of the specimens treated in a combined way failed cohesively by cracking the ceramic coating. In the control and sandblasted subgroups of the SLM-processed alloy, the porcelain coating was destroyed through adhesive-cohesive route: adhesive along the metal/oxide layer interface, and cohesive through the porcelain. Ceramic fracture in the bond- and combined treated subgroups was observed to occur adhesively along the bond/porcelain interface, and cohesively through the bond and porcelain.

Abstract: As a result of the studies of wood flame retardant effect on ignition, the parameters of flame propagation and combustion suppression were established, which makes it possible to influence this process. It has been proven that the creation of a protective layer on the surface of wood prevents it from heating up to a critical temperature. At this moment, a certain amount of combustible gases is released, that is, intense decomposition and ignition occurs. This knowledge makes it possible to establish the dependence of the process of inhibiting the burning rate of wood on the quality of fire protection and the properties of the applied protective mixtures. By experimentally examining wood samples, it was established that the sample without treating caught fire on 52 s and in 100 seconds the flame spread over the entire surface, the sample fire-retardant "FIREWALL-ATTIK" did not catch fire, impregnating solution ВС-13 and "FIREWALL-SV-1", namely a mixture of 271.1 g/m², took 570 and 560 s, the flame spread to the surface only in areas closer to the source, the highest flue gas temperature of 86 and was reached more than 5 times faster, and the flammability index decreased to 4. For the sample protected by "FIREWALL-LAC" ignition occurred in the last second, the flame was recorded at level 0. For the sample fire-protected by "FIREWALL-WOOD" coating no ignition occurred, combustibility index is 0. Due to this, it became possible to determine the conditions for changing the combustion barrier to heat conductivity. Correspondence between the obtained experimental results of the wood burning rate and the analytically calculated equations was found.Taking into account the above, there is a basis for asserting the possibility of purposeful management of the processes of protecting wood from fire by applying fire-retardant mixtures, which under certain conditions are able to create a protective layer on the surface of the material, which restrains the growth of the rate of wood burning.