Surface Mechanical Properties Research Articles

Nanomaterial-Enhanced Sizings: Design and Optimisation of a Pilot-Scale Fibre Sizing Line

This study focuses on the development of a pilot-scale sizing line, including its initial design and installation, operational phases, and optimization of key process parameters. The primary objective is the identification of critical parameters for achieving a uniform sizing onto the fibres and the determination of optimal conditions for maximum production efficiency. This investigation focused on adjusting the furnace desizing temperature for the removal of commercial sizing, adjusting the drying temperature, as well as optimizing the corresponding residence time of carbon fibres passing through the furnaces. The highest production rate, reaching 1 m sized carbon fibres per minute, was achieved by employing a desizing temperature of 550 °C, a drying temperature of 250 °C, and a residence time of 1 min. Furthermore, a range of sizing solutions was investigated and formulated, exploring carbon-based nanomaterial types with different surface functionalizations and concentrations, to evaluate their impact on the surface morphology and mechanical properties of carbon fibres. In-depth analyses, including scanning electron microscopy and contact angle goniometry, revealed the achievement of a uniform coating on the carbon fibre surface, leading to an enhanced affinity between fibres and the polymeric epoxy matrix. The incorporation of nanomaterials, specifically N2-plasma-functionalized carbon nanotubes and few-layer graphene, demonstrated notable improvements in the interfacial shear properties (90% increase), verified by mechanical and push-out tests.

Surface-Modified Diopside-Reinforced PCL Biopolymer Composites with Enhanced Interfacial Strength and Mechanical Properties for Orthopedic Applications.

The phase separation of ceramics in a biopolymer matrix makes it challenging to achieve satisfactory mechanical properties required for orthopedic applications. It has been found that silane coupling agents can modify the surface of the bioceramic phase by forming a molecular bridge between the polymer and the ceramic, resulting in improved interfacial strength and adhesion. Therefore, in the present study, silane-modified diopside (DI) ceramic and ε-polycaprolactone (PCL) biopolymer composites were fabricated by injection molding method. The silane modification of DI resulted in their uniform dispersion in the PCL matrix, whereas agglomeration was found in composites containing unmodified DI. The thermal stability of the silane-modified DI-containing composites also increased. The Young's modulus of the composite containing 50% w/w DI modified by 3% w/w silane increased by 103% compared to composites containing 50% w/w unmodified DI. The biodegradation of the unmodified composites was significantly high, indicating their weak interfacial strength with the PCL matrix (p ≤ 0.001). The osteoconductive behavior of the composites was also validated by in vitro cell-material studies. Overall, our findings supported that the silane-modified composites have improved surface roughness, mechanical, and osteoconductive properties compared to the unmodified composite and have the potential for orthopedic applications.

Morphological and functional characterization of electroplated Ni-graphene composite coatings

Composite coatings (CECs) are providing a unique technological advantage for improving mechanical and tribological surface properties. Among different methods, electrodeposition is one of the most exploited to produce composite surface coatings on metal substrates. However, the process parameters affect graphene distribution, coating morphology and performance. This paper investigates how different deposition conditions influence the inclusion of large Graphene nanoplates (GnPs) in a Nickel matrix and the coating morphology and tribological performance. Set the process condition such as electrical parameters and the galvanic bath, the work focuses on the stirring rate effect. To this end, Ni-GnP coatings were obtained by a laboratory setup and evaluated through surface profilometry, SEM characterization and a dry-sliding linear reciprocating wear test. The results highlight the influence of stirring on coating uniformity. The low stirring rate allows larger particles to be embedded, which are not thoroughly covered; however, they act as a solid lubricant and reduce the friction coefficient.

Investigation on Enhanced Machinability of SiC Ceramics through Photocatalytic Vibration Composite Polishing.

The problems of low polishing efficiency and serious surface damage in the processing of silicon carbide (SiC) ceramics are well-known. In view of the above problems, a new method of photocatalytic vibration composite polishing (PVCP) combined with a compound control strategy was proposed. A vibration-assisted device was developed, and a compound control system was designed for the device to improve the trajectory tracking accuracy. Experiments were carried out to verify the effectiveness of the vibration-assisted device and the compound control system. In addition, methyl orange degradation and fading experiments, redox potential measurement experiments, and SiC ceramic surface hardness characterization experiments were carried out to reveal the effects of vibration and photocatalytic parameters on polishing solution oxidation and SiC ceramic surface mechanical properties. Finally, the effects of photocatalysis, vibration frequency, amplitude, and the compound control system on the polishing effect were analyzed. The results show that when the UV intensity is 100%, the polishing force is 3-4N, the vibration frequency is 400 Hz, the amplitude is 15 μm, and the surface roughness of SiC ceramics is reduced by about 11 nm after the introduction of the compound control system, which verifies the effectiveness of the combination of the compound control system and PVCP.

A Study on Surface Quality and Mechanical Property Improvement Through Mechanical Surface Treatment of Amorphous Metal

A Study on Surface Quality and Mechanical Property Improvement Through Mechanical Surface Treatment of Amorphous Metal

TIG assisted surface finish enhancement in MIG-based wire arc additive manufacturing

TIG arc treatment was explored to enhance the surface finish of wire arc additive manufactured (WAAM) parts, addressing issues of waviness and roughness. It offers precise control over input parameters providing an economical solution for selective thermal surface treatment. This study investigates the influence of peak current on surface finish and associated impact on hardness. A hybrid MIG-TIG process was employed which minimised the waviness efficiently, however resulted in low hardness, requiring further treatment to restore hardness. This approach reduced surface roughness by ∼ 40 %, offering efficient and cost-effective selective treatment, with the potential to improve surface quality and mechanical properties.

Effect of Different Disinfectant Solutions on the Properties of Gutta Percha Cones

The purposes of this study was to investigate the effect of sodium hypochlorite (SH) and chlorhexidine (CH) disinfectant solusions on surface texture and mechanical properties of gutta percha (GP) cones at different concentrations and time intervals. In this study, 190 GP cones size 100 were used. SH solutions at (1%, 2.5%, 5.25%) and CH solutions at (1%, 1.5%, 2%) were used for GP cones disinfection by submerging cones for (10 min, 15 min, 20 min) in each of the solutions to be tested, in which 10 cones were used for each disinfectant solution at every time interval, and 10 cones remain fresh as a control. Surface texture determined by stereomicroscope. Mechanical properties measured by digital universal testing machine. SH solutions at (2.5% and 5.25%) decrease tensile strength, increase modulus of elasticity, decrease percentage of elongation , and left a numerous pitting on GP cones after (10, 15, 20) minutes of disinfection which were significantly different from fresh control cones, 1% SH , and CH at (1%, 1.5%, 2%).Within the limitation s of this study, SH at 1% and CH at (1%, 1.5%, 2%) concentrati ons can be considered the most safe solutions for disinfection of GP cones.

Study on wear resistance and toughness of calcium ion crosslinked cellulose nanofibers/multi-walled carbon nanotubes/hexagonal boron nitride hybrid reinforced Ni[sbnd]B composite coatings on N80 steel

This study developed a novel NiB/Ca-CNFs/MWCNTs/h-BN coating on N80 steel. The disadvantages of hexagonal boron nitride (h-BN) were improved by creatively combining multi-walled carbon nanotubes (MWCNTs), cellulose nanofibers (CNFs), and calcium ion cross-linking strategies. This led to the creation of Ca-CNFs/MWCNTs/h-BN hybrids, which were then doped into NiB coatings by varying pulse current densities. The results demonstrated that the surface morphology, mechanical properties, and toughness of the composite coating are all influenced by the Ca-CNFs/MWCNTs/h-BN doped at various current densities. Meanwhile, the NiB/Ca-CNFs/MWCNTs/h-BN (4 A/dm2) coating has the greatest microhardness (902.42 Hv) and the smallest friction coefficient (0.487) under reciprocating dry sliding friction conditions of Si3N4 friction balls. In addition, the results of nanoindentation and tensile tests show that the elastic modulus of NiB/Ca-CNFs/MWCNTs/h-BN (4 A/dm2) composite coating is 194.096 MPa and the tensile elongation is 12.2 %.

Development of Mucoadhesive Buccal Films Containing Triamcinolone Acetonide by using Co-solvent Systems

This work aimed to develop mucoadhesive buccal films containing triamcinolone acetonide (TA), which shows local anti-inflammatory activity. A thin film layer was formulated from polyvinyl alcohol (PVA) by the solvent casting method. The solubility of TA and the ability of the co-solvents to produce films were evaluated. The optimal co-solvents were chosen to prepare the film. Pharmaceutical properties of the film, including uniformity of weight, thickness, mechanical property, wetting time, mucoadhesion, TA content, and release, were evaluated. Furthermore, the cytotoxicity and scratch assay were assessed for the in vitro cell line. Among the co-solvents, the system consisted of ethanol, distilled water, and an individual plasticizer (glycerin and polyethylene glycol 400 (PEG 400)), which showed promising co-solvents for TA solubility and film formation. The films were clear and colorless, with a smooth surface and good mechanical properties. PEG 400-contained film formulation had higher mechanical properties and faster wetting time than glycerin. Both films had similar mucoadhesive properties, although the TA content differed slightly, and a rapid release of TA from the films was observed. However, PEG 400-contained film offered a slightly faster TA release than glycerin. The films were non-toxic to gingival fibroblast cells. However, they decreased the cell growth and migration compared to the control. According to this research, co-solvents increased TA solubility and produced good characteristic buccal mucoadhesive films containing TA. Keywords: Triamcinolone acetonide, Co-solvents, Film, Mucoadhesive property

Preparation of Ni–Mo/GO composite coatings with strengthened mechanical properties and enhanced corrosion resistance

Ni–Mo/GO coatings in thickness of 1.5–3 μm were electrodeposited from a citrate bath containing nickel sulfate, sodium molybdate, GO and SDS. The impacts of GO nanosheets on the surface morphology, structure, mechanical properties and corrosion resistance of the Ni-Mo matrix were explored. Ni-Mo alloy shows an amorphous phase with a smooth and compact surface. The codeposited graphene oxide can refine Ni-Mo microstructure, but also can lead to rougher surfaces with defects. Coefficient of friction (COF) of Ni-Mo matrix decreased, and wear resistance and hardness increased in the presence of GO. The corrosion resistance of Ni–Mo/GO would be improved only if GO concentration exceeded 0.2 g L−1. The preferred concentration of GO was 0.2–0.3 g L−1, which showed satisfactory anti-corrosion performance. The corrosion resistance depends not only the amount of GO present but also its dispersed arrangement and distribution. A higher content of GO, a dispersion of particles parallel to the substrate and uniform GO distribution in the metallic matrix can hinder the diffusion of corrosive species, leading to an improved corrosion resistance.

Enhancing mechanical properties and surface quality of FDM-printed ABS: A comprehensive study on cold acetone vapor treatment

The development of additive manufacturing (AM) technologies has significantly advanced fabrication capabilities, yet achieving optimal surface quality and mechanical properties in end-use products is challenging. The primary objective of this study is to improve specific characteristics of 3D-printed components by employing a chemical post-processing technique including acetone. This technique is specifically applied to acrylonitrile butadiene styrene (ABS) material, utilizing a customized mechanical cold-vapor system. A complete investigation was undertaken to assess the effects of treatment on many factors, such as temperature, solvent volume, and exposure duration, on the tensile strength, physical dimensions, and mass of the ABS samples. Acetone post-processing has notably improved tensile strength, influenced by treatment duration and temperature and has led to dimensional changes such as a slight length reduction and increases in width and thickness. Furthermore, the mass of the samples exhibited variability upon acetone treatment, which was shown to be dependent on both the ambient temperature and the duration of solvent exposure. The tensile strength was assessed under various conditions, showing a significant enhancement at higher temperatures and longer exposure times. These results, demonstrating smoother surfaces and a tensile strength increase of up to 20% at 65 °C, underscore the efficacy of our techniques in modifying the mechanical and physical properties of 3D-printed ABS components. This innovative approach provides valuable insights into the relationship between post-processing conditions and ABS properties, enriching the body of knowledge in AM technology.

Investigation of Surface Residual Stress, Mechanical Properties, and Metallurgical Characterization of Inconel 625 Multilayer Thin-Wall Component Using Cold Metal Transfer Technique

Investigation of Surface Residual Stress, Mechanical Properties, and Metallurgical Characterization of Inconel 625 Multilayer Thin-Wall Component Using Cold Metal Transfer Technique

Mechanical properties and oxidation corrosion resistance of phosphate ceramic coating enhanced by SiO2‐BNNSs material

AbstractA method of preparing SiO2‐BNNSs hybrid material by surface modification of boron nitride nanosheets (BNNSs) with SiO2 was proposed to improve the dispersion of BNNSs in the coatings. Then, phosphate ceramic coatings with BNNSs and SiO2‐BNNSs were prepared on stainless steel (304) by spraying. Characterization of BNNSs and SiO2‐BNNSs by X‐ray diffraction, Fourier transform‐infrared, Raman, and scanning electron microscopy proved the success of hybridization. The surface morphology and mechanical properties were conducted to characterize the protective performance of the coating. Simultaneously, the phase composition and electrochemical properties of the coatings after high‐temperature oxidation were studied. The results showed that ceramic coatings had low surface energy with a contact angle of 102.41° when .4 wt.% SiO2‐BNNSs was added. Compared with BNNSs coating, the mechanical properties of SiO2‐BNNSs coating were significantly enhanced, the hardness of .4 wt.%SiO2‐BNNSs coating was as high as 170 HV, and the interface bonding strength was 12.24 MPa. For the oxidation corrosion resistance, .4 wt.% SiO2‐BNNSs coating under oxidation at 400°C for 50 h had the minimum corrosion current density and maximum impedance, which were .864 μA/cm2 and 177 kΩ/cm2, respectively, this indicated that SiO2‐BNNSs coating could still maintain excellent oxidation corrosion resistance under high‐temperature conditions for a long time.

Effects of laying angles on stainless steel fabricated by selective laser melting

This study aimed to investigate the effects of laying angles (0°, 15°, 30°, 45°, 60°, 75° and 90°) on surface roughness, density behaviour, residual stress, and mechanical properties of 316L stainless steel components fabricated by selective laser melting. The findings revealed that the 15° samples exhibited the best surface quality, while the 90° samples had a roughness of up to 18μm due to the staircase effect and balling behaviour. The residual stress of the samples decreased gradually as the laying angle increased. The density of the 0° samples reached 99.92%, whereas the 90° samples were only 99.62%. The 90° components exhibited a good tensile strength of 678 MPa, while the 0° samples had lower tensile strength.

Preparation and Modification of Collagen/Sodium Alginate-Based Biomedical Materials and Their Characteristics.

(1) Background: Collagen and sodium alginate are commonly used in the field of biomedical materials due to their excellent biocompatibility. This study focuses on the preparation, modification, and characterization of collagen/sodium alginate (C/SA)-based biomedical materials. (2) Methods: The characteristics, including surface chemistry, mechanical properties, hygroscopicity, and porosity, were analyzed. The hemostatic activity in vitro was measured using a blood clotting assay and dynamic blood clotting assay. (3) Results: The results from microstructure and porosity measurement revealed that all of the sponges exhibited a porosity of more than 95 percent. The sponge cross-linked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) showed better tensile strength and lower elongation at break. The sponges cross-linked with EDC/NHS and oxidized sodium alginate (OSA) exhibited the highest hygroscopicity in comparison with the uncross-linked sponge. (4) Conclusions: Our study demonstrated that the C/SA-based material we prepared exhibited a high level of porosity, enabling efficient absorption of tissue exudate and blood. Additionally, the materials revealed excellent hemocompatibility, making them suitable for use as a hemostatic dressing in the field of biomedical materials.

Characteristics of novel cycloaliphatic epoxides based on UV-induced cationic ring-opening polymerization for plastic coatings

Cationic ring-opening polymerization (CROP)-capable cycloaliphatic epoxide monomers bearing a benzyl ether group (CE-BEs) were developed as glass-replacement plastic coatings for lightweight automobiles. Three different monomers of bis(((7-oxabicyclo[4,1,0]heptan-3-yl)methoxy)methyl)benzene isomers were synthesized to provide the cycloaliphatic epoxide functional groups. 1H and 13C nuclear magnetic resonance and Fourier transform infrared (FT-IR) spectroscopic analyses confirmed that the monomers were successfully synthesized. The shear viscosity and real-time crosslinking behavior of the CROP coatings were investigated using a rheometer. In particular, the release of thermal energy via CROP under UV irradiation was monitored using differential scanning photocalorimetry. The reaction conversion of cycloaliphatic epoxides by CROP before and after UV irradiation was verified using FT-IR spectroscopy. The transparency of the CROP coating films cured on a polycarbonate substrate was measured using an ultraviolet–visible spectrophotometer, and their adhesion was confirmed using cross-cut tests. For characterization of the surface mechanical properties, a nanoindentation tester and a nanoscratch tester were used in conjunction with an atomic force microscope to evaluate the surface hardness and scratch resistance, respectively. In addition, the thermomechanical properties of the cured CROP coating films were investigated using a rigid-body pendulum tester operated in dynamic physical mode. The ternary coating systems with CE-BEs were found to exhibit high photoreactivity, a dense crosslinking density, a transparent appearance, and enhanced adhesion and mechanical properties, making it suitable for glass-replacement plastic coatings.

Vickers Hardness Mechanical Models and Thermoplastic Polymer Injection-Molded Products’ Static Friction Coefficients

The surface mechanical properties of thermoplastics are crucially important for evaluating molded products’ vulnerability to scratching. Because surface mechanical properties reflect material performance directly in terms of durability and frictional behavior, understanding and modeling them is important for industry and research. This emphasizes the surface mechanical properties of Vickers hardness and the static friction coefficient, with attempts to model them as functions of stress at yield initiation. Vickers hardness can be related to the compressive stress at yield initiation. The static friction coefficient can be modeled as a function of the surface shear strength and Vickers hardness. This research has improved our understanding of thermoplastics’ surface mechanical properties and has enabled the prediction of the scratch performance of molded products and the provision of effective indicators for material design.

Fabrication of a novel aesthetic orthodontic bracket and evaluation of friction properties between PEEK and stainless steel wires.

Polyetheretherketone (PEEK) is a polyaromatic semi-crystalline thermoplastic polymer with mechanical and lubrication properties favorable for biomedical applications. Despite of its aesthetic appearance, ceramic brackets are unsatisfactory in brittleness and thickness, while PEEK is a potential material for aesthetic orthodontic brackets. To fabricate a novel aesthetic orthodontic bracket and evaluate friction properties of PEEK and stainless steel wires. All polyether ether ketone (PEEK) and ceramic samples disks were made into disks (diameter, 5 mm; thickness, 2mm). The tested surfaces of PEEK were ground with #600, #800 and #1200 SiC papers, followed by polishing with Sof-Lex kit (3M ESPE, USA). The surface roughness was tested using a laser profilometer device (VK-X200, Keyence, Japan). The COFs of the specimens and stainless steel (SS) archwires were tested using a Universal Micro-Tribotester (UMT-3, Bruker, USA). The wear scratches on the materials' surfaces were examined by using a scanning electron microscope (SEM) (Hitachi SU8010). The elastic modulus and hardness of samples were examined with a nano-indenter (XP, Keysight Technologies, USA). The mean surface roughness of PEEK and Ceramic are 0.320 ± 0.028 μm and 0.343 ± 0.044 μm, respectively. PEEK has a lower Friction coefficient than Ceramic and the difference between the two groups was statistically significant (P< 0.05). The abrasive wear of Ceramic was the main wear style and was characterized by the observation of chipping fractures, while PEEK surface looked smooth without obvious scale-like desquamations and granular debris, indicating adhesive wear. Within the limitations of the present study, PEEK shows lower coefficient of friction than ceramic. PEEK has excellent properties such as low friction coefficient, smooth surface and good mechanical properties, and thus meets the requirements for orthodontic brackets. It is considered as a potential bracket material with both low friction and aesthetic performance.

Effect of Hirtisation treatment on surface quality and mechanical properties of AlSi10Mg samples produced by laser powder bed fusion

Laser Powder Bed Fusion (L-PBF) provides a larger design freedom than conventional manufacturing techniques. Surface post-processing is widely investigated to improve the roughness of as built L-PBF parts by reducing powder sintered to the surface and the staircase effect, but it becomes even more important to guarantee a smooth surface if support structures are included for tilted overhanging structures. This study focuses on L-PBF AlSi10Mg samples with a building angle of 30° with respect to the baseplate. This building angle inevitably requires support structures. The study investigates if a hybrid surface treatment combining chemical and electrochemical polishing, called Hirtisation®, removes the support structure and to what extent it improves the surface roughness of samples with a 30° building angle. Currently, the results of surface treatments are mostly reported on vertically built samples while down-facing areas of samples with a lower building angle are typically the roughest areas of the samples causing crack initiation in fatigue. Roughness, defect population, residual stresses, microstructure, fatigue, and tensile properties are studied to investigate correlations with the physical effect of Hirtisation. A porous zone is observed in the down-facing area close to the support structures of as built samples. Hirtisation removed successfully the support and the porous area. In the down-facing roughest area, the average values of the average roughness, mean roughness depth and deepest valley depth are reduced by respectively 56,5%, 58,7% and 51,5% by Hirtisation compared to the as built state. The deepest valley measured reduced from 155,5 µm to 74,4 µm. Hirtisation combined with annealing increased the fatigue resistance at a stress amplitude of 120 MPa with a factor 3,1 compared to the as built state and with a factor 2,7 compared to the annealing state. The improved fatigue resistance is linked to halving the deepest valley depth as well as a change in the residual stress at the outer surface from tensile stresses after annealing to a small compressive stress after Hirtisation which counteracts the tensile load in fatigue. Hence, Hirtisation reduces roughness, inverses a tensile residual stress at the outer surface to a small compressive residual stress. In addition, the chemical-electrochemical process allows to access areas which are impossible to post-process with e.g. sandblasting or vibratory polishing. These conclusions make Hirtisation interesting for further investigations for future applications, however the deepest valley depth could be reduced more by increasing the material removal in the process to improve the fatigue life more.

Water drops on nanofiber-coated substrates: Influence of wall temperature and coating thickness on hydrodynamics and wall heat flux distribution

Heat and mass transport during drop impact or a gentle deposition onto a heated substrate depends on the surface chemistry, morphology, thermal and mechanical properties of the substrate, as well as the substrate temperature. In particular, if a substrate is coated with a porous layer of a wettable material, the drop spreading is accompanied by the imbibition of a liquid into the layer. The wetted area is significantly enhanced in comparison with the area which can be covered by a drop spreading over a bare substrate. As a result, the liquid evaporation rate increases and the evaporation time decreases. Understanding the interaction between the liquid spreading, imbibition and evaporation is important, both for enhancement of heat transfer in cooling applications and for functionalizing of porous media. In our experimental studies, a disk of infrared-transparent calcium fluoride is used as the base substrate. The disk is coated with a submicrometer layer of black chromium nitride and an electrically conductive chromium layer, used for heating of the substrate by electrical current. Nanofiber coating layers are applied on top of the chromium layer using electrospinning. The dynamics of drop spreading is captured by a high-speed camera in a side view, the imbibition is observed with a top view camera, and the temperature distribution at the substrate-coating interface is captured by an infrared camera. Based on the transient temperature field, corresponding heat flux distributions are determined. For the detailed analysis of the interplay between hydrodynamics and heat transfer, the nanofiber coating thickness and substrate temperature have been varied. It has been found that the drop drying time and maximal imbibed area depend non-monotonously on the coating thickness. Changing the initial wall temperature leads to qualitatively different distribution of the heat flux at the substrate surface.