Crack-free Surface Research Articles

Effect of Partial Replacement of Wheat Flour by Flour from Extruded Sunflower Seed Kernels on Muffins Quality.

The use of new types of raw materials to improve the quality and nutritional value of products is an important trend in flour confectionery. Flour from extruded sunflower seed kernels (FESSK), the by-product of oil production, was used as a new ingredient in muffin formulation. Analysis of physicochemical and nutritional properties of muffins prepared with FESSK, which was added in the amounts of 5, 10, and 15% to the total weight of mixture of wheat and rye flours, as well as their sensory evaluation, wereperformed. According to the sensory evaluation, the muffins with FESSK had a pleasant, nutty and sunflower aroma, and the best results were shown by muffins with 10% of FESSK. Addition of FESSK, 10%, led to an increase of the content of protein by 24.7%, fat by 16.9%, fiber by 23.3%, ash by 16.9%, and a decrease of content of total carbohydrates by 5.2% and sugars by 16.2%. Enriched muffins had improved texture characteristics, particularly, smooth, crack-free surface, soft, and elastic crumb with well-developed porosity and small, evenly distributed, thin-walled pores. The FESSK could be recommended as an ingredient for improving the nutritional and technological properties of flour confectionery products.

Impact of thick N-polar AlN growth on crystalline quality and electrical properties of N-polar GaN/AlGaN/AlN FET

In this study, we attempted to fabricate N-polar GaN/AlGaN/AlN heterostructure FET by changing the thickness of the AlN layer. An Al-polar tiny-pit AlN layer and a polarity inversion method were used to grow N-polar AlN on vicinal sapphire via the metal-organic vapor phase epitaxy. The samples with an AlN thickness of up to 3.4 μm exhibited a crack-free surface. Additionally, the twist component of the crystal quality improved with an increasing AlN thickness. Consequently, the mobility, sheet conductivity, and surface flatness improved. The FET fabricated from the sample with a thicker AlN layer achieved a higher drain current of 279 mA mm−1 at a gate bias of V G = 3 V.

A study on the performance of super duplex stainless steel cladding over mild steel using a CMT welding

Low carbon steels can be cladded with super-duplex stainless steels to enhance the surface’s mechanical and wear properties. The current study examines the impact of process parameters on weld bead geometry and dilution % during cold metal transfer (CMT) cladding of super duplex stainless steel 2507 over low carbon steel. Response Surface Methodology (RSM) with a Central Composite Design matrix was used to optimize the process parameters (welding current, welding speed, and nozzle to workpiece distance (NTD)). The adequacy of the model was checked using an ANOVA analysis. The optimal bead width, height, penetration, and dilution values were 8.05 mm, 4.52 mm, 1.56 mm and 14.64%, respectively. The ideal input parameters were 200 A of welding current, 4.64 mm/s of welding speed, and 14 mm of NTD. The welding speed is the most dominant parameter, followed by the welding current and NTD. The cladding samples were prepared from the optimal parameters. The CMT-clad layer’s microstructure, microhardness, and wear properties were also evaluated. The results indicate a dense crack-free and non-porous clad surface was obtained under optimal conditions.

Microstructural, mechanical and neutron-attenuation properties of apatite-wollastonite doped by SiO2, Fe2O3, and TiO2

In this study, the preparation, physical characteristics, microstructural attributes, and fast neutron (FN) removal parameters of apatite-wollastonite (AW)-containing GCs doped with 10 % SiO2, Fe2O3, and TiO2 were reported. Glass-ceramics containing the AW crystal structure within the SiO2–CaO–Al2O3–MgO–P2O5–CaF2 glass system were prepared and doped with 10 % SiO2, Fe2O3, and TiO2 by weight. The microstructural and chemical evolution of the glass-ceramics were studied using SEM/EDS. The density and Vicker hardness of the samples were experimentally evaluated, while the fast neutron removal cross-sections (ΣR) were computed using standard equations. The SEM micrograph showed densely crystallised and crack-free surface surfaces. Silicon and titanium additions did not cause a significant increase in density. However, Fe doping had a higher effect on density. The values of ΣR for pristine, SiO2, TiO2, and Fe2O3-doped AW were found to be 0.0796 cm−1, 0.0832 cm−1, 0.0869 cm−1, and 0.0904 cm−1, respectively. Compared to some other materials, such as polymers, AW-10Fe showed better attenuation for fast neutrons. The investigated ceramics could be used in tissue engineering and fast neutron moderation functions.

A comparative study of laser fluence effect on surface modification and hardness profile of austempered ductile iron

The impact of laser transformation hardening (LSH) and Laser surface melting (LSM) on an austempered ductile iron (ADI) alloy was investigated. Various laser fluences (J mm−2) were irradiated on the ADI specimens, obtained by different beam powers and scanning speeds to reach the optimum parameters to attain a surface with a good combination of high hardness and deep hardened depth, together with obtaining minimal distortion and crack-free surface. ADI surfaces were treated by means of high-power Nd:YAG laser in continuous wave mode. A detailed investigation of the obtained microstructure was characterized via optical and scanning electron microscopy attached to an EDX analyzer as well as X-ray diffraction analysis. Such a wide laser fluence range has a considerable effect on the achieved microstructure. A process parameter map was established which indicated that three different laser treatments were induced under such values of laser fluences: a laser transformation hardening, a partial laser melting, and a complete laser melting. The results revealed that to produce a hardened microstructure, specimens have to be operated within a very small range of laser fluence from 9.6 up to 29 J mm−2, achieving surface hardness values around 900 HV0.1 and depths of approximately 184–700 μm, respectively. Meanwhile, partial melting of the treated layer took place at a medium energy density range from 37 to 112 J mm−2, by a further increase in laser fluence (120–360 J mm−2), complete melting occurred which resulted in a deeper treated layer that reached 3.5 mm with an increase in microhardness value to almost 1100 HV0.1 at 360 J mm−2. The obtained microstructure in case of low laser fluence consisted of an austenite dendritic structure with undissolved graphite nodules, however, at medium and high laser fluence, the microstructure contains large cementite plates, iron-silicon carbides, a small area of ledeburite structure, and some retained austenite. The quantitative amounts of such phases directly depend on the applied laser fluence. Such phases were identified by means of EDX analysis.

Cracking mechanisms and microstructure of Co-based surfacing layer during high-temperature impact fatigue

In this paper, high-temperature impact fatigue (HTIF) was carried out on a Co-based surface layer cladded by TIG welding, and cracks emerged at 400-cycle condition. The reasons for cracking were investigated from three aspects: microstructure, stress distribution, and crystal orientation. Crack generation was induced by high stress distribution in eutectic carbides at grain boundaries and the great disparity in orientations between grains on two sides of the crack path. The microstructural advantage for cracking behavior played a key role in emergence of cracks, which was verified by the investigation and comparison of three distances from the weld interface. Moreover, the interface microstructure of Co-based layer and FB2 substrate was characterized by transmission electron microscopy, and the phase composition of the weld interface comprised FeCo and M23C6. The results presented that the addition of Ni-based transition layer caused the acquisition of the crack-free surface layer after HTIF. Finally, microhardness test was conducted on samples with and without a transition layer. The hardness of Co-based surface layer without the transition layer was mainly affected by the transformation of carbides, dilution of Fe, and work hardening during HTIF. The hardness of Co-based surface layer with the transition layer showed minimal change during HTIF, and this finding was attributed to the slight variation in the microstructure.

The electrical and dielectric features of Al/YbFeO3/p-Si/Al and Al/YbFe0.90Co0.10O3/p-Si/Al structures with interfacial perovskite-oxide layer depending on bias voltage and frequency

In this investigation, thin films of YbFeO3, both in its pure form and doped with 10% Co, were fabricated on a p-Si substrate at 500 °C through the radio-frequency magnetron sputtering method. Examination via Scanning Electron Microscopy demonstrated a porous texture for the pure sample, contrasting with a smooth and crack-free surface post-Co doping. Analysis via X-ray photoelectron spectroscopy unveiled Yb’s 3 + oxidation state, alongside the presence of lattice oxygen, oxygen vacancies, and adsorbed oxygen evident in Gaussian fitting curves. Photoluminescence spectroscopy revealed an augmented emission intensity, likely attributed to increased defect initiation in the Co-doped specimen. Moreover, Raman spectroscopy was employed to identify vibration modes in the examined samples, demonstrating shifts in Raman peaks indicative of Co substitution and subsequent distortion in the crystal structure of YbFeO3. Electrical assessments were conducted at room temperature (300 K) under ambient conditions, employing voltage and frequency as variables. Capacitance–voltage measurements illustrated the emergence of an accumulation, with depletion and inversion regions manifesting at different frequencies based on the applied voltage, attributed to the YbFeO3 interfacial layer at the Al and p-Si interface. The conductance-voltage characteristics indicated that the structure exhibited maximum conductance in the accumulation region. Series resistance for these configurations was deduced from capacitance-conductance-voltage measurements, indicating a dependence on both bias voltage and frequency. The doping process led to a reduction in capacitance and series resistance, accompanied by an increase in conductance values. After obtaining corrected capacitance and conductance parameters, it became evident that series resistance significantly influences both parameters. Interface state density (Nss), determined through the Hill-Coleman relation demonstrated a decreasing trend with increasing frequency. The pure sample exhibited higher interface state density compared to the Co-doped sample at each frequency, highlighting that the 10% Co-doped YbFeO3 thin film enhances the quality of the metal–semiconductor interface properties compared to the pure contact.

A spacer-based approach for localized Joule heating in membrane distillation

Membrane distillation (MD) is a versatile low-temperature separation process used for desalinating saline solutions with high salt rejection rates. Its current drawbacks include low flux and high energy demand. This study presents localized electrically induced heating using ceramic-coated metallic spacers to improve MD performance. We coated Ni-Cr spacers with MgO via electrolytic deposition and calcination, optimizing for a crack-free protective surface. Smaller wire diameter Ni-Cr exhibited superior heating. When a periodic current of 0.2 A cm−2 was applied, permeate flux increased by 15% although energy consumption only increased by 4%. Continuous supply of high-grade electrical energy added no further performance improvement as compared to periodic application. Our work highlights a spacer-based approach for localized Joule heating in MD systems without compromising membrane structure, while exploring coating systems to protect conductive spacers and optimizing schemes for electrically controlled performance.

Metallization of polypropylene substrates through surface functionalization and physical vapor deposition of chromium coatings

Physical vapor deposition (PVD) of chromium coatings represents an interesting alternative to electroplating to obtain metallized plastic parts for a variety of manufacturing sectors. This process is however hampered by the limited adhesion of the metallic layer on the underlying polymeric substrates. Within this context, PVD metallization of polypropylene substrates has so far been particularly challenging given the low surface energy and poor wettability of this commodity plastics. To address this issue, a comprehensive approach is proposed here to enable the production of PVD-metallized PP substrates with excellent and stable interlayer adhesion. The adhesive properties of the PP substrate are modified by a selective UV-induced photografting process in which vinyl-, glycidyl- or 2-hydroxyethyl methacrylate species are covalently attached to the PP surface, as confirmed by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and surface wettability measurements. Based on the chemistry of the photografted functionality, different resin systems are selected and investigated for use as primers to enable subsequent chromium deposition, including acrylic, epoxy and polyurethane systems. The effect of the photografting process on the adhesion between PP and the primers is systematically assessed by means of pull-off tests, highlighting a significant improvement of the adhesion force after surface functionalization with appropriate grafting agents. Finally, functionalized PP substrates are chromated through PVD, obtaining homogeneous and crack-free chromium surfaces upon judicious selection of suitable primer-grafting agent combinations. This also led to outstanding interlayer adhesion and micromechanical performance. This work provides the first demonstration of chromium-metallization of PP substrates via PVD for metallized plastic components with excellent surface characteristics, and paves the path for the design of mechanically durable and aesthetically-compliant PVD-metallized PP components.

Corrosion inhibition of mild steel by Praecitrullus fistulosus (tinda fruit and peel) extracts

Metal corrosion has recently emerged as a growing concern, impacting both local and industrial operations and disrupting conventional production methods. The utilization of green inhibitors to mitigate the metal degradation has garnered extensive attention from researchers and industrial professionals due to their prominent advantages: high efficiency, cost-effectiveness, and eco-friendliness. A novel ecofriendly inhibitor was prepared from Praecitrullus fistulosus (tinda fruit and peel) for mild steel (MS) corrosion in 1 M HCl. The presence of phenol, 3,5-bis (1,1-dimethyl ethyl)-, 9-octadecenoic acid, methyl ester, hexadecanoic acid 15-methyl-, methyl ester, 9, 12-octadecadienoic acid, methyl ester, 9, 12, 15-octadecatrienoic acid, methyl ester, (Z,Z,Z-), ascorbic acid, and phytol were identified as major constituent through LC/MS analysis of tinda extracts. The existence of these compounds was further confirmed through FTIR analysis, which shows the presence of various functional groups, such as -OH, CO, C-O-C, CC, and aromatic rings in the tinda extracts. Electrochemical and gravimetric analyses were used to investigate the inhibitory effect of tinda extracts. Outcomes of Tafel analysis revealed that both tinda extracts significantly reduced the corrosion current as compared to blank and achieved 83.73 % and 87.59 % inhibition efficiencies at 200 mg L−1 of tinda peel extract (TPE) and tinda fruit extract (TFE), respectively. The change in corrosion potential (Ecorr) was within an ±85 mV range compared to that of the uninhibited system, indicating that both tinda extracts demonstrated a mixed-type inhibition behavior. During adsorption studies, the best fit was obtained for the Langmuir adsorption model. The obtained values of standard Gibbs free energy (ΔG°ads) for TPE and TFE lie between −20 and − 40 kJ mol−1 but close to −20 kJ mol−1, which reveals preferential physical adsorption of the extracts on the metal surface. Thermodynamic parameters, including activation energy, enthalpy, and entropy, were computed across the temperature range of 303 to 323 K, suggesting that corrosion occurs spontaneously by the endothermic process. FESEM analysis depicted that inhibited systems exhibited smooth and crack-free surfaces as compared to blank system. AFM images demonstrated that surface roughness was significantly reduced for the inhibited system. In EDX analysis, the weight percentage of Cl was reduced in the presence of tinda extracts as compared to blank, and in XRD analysis, iron chloride (FeCl2) peak did not appear in the presence of inhibitor but it was in the uninhibited system. All surface-related findings signify that tinda extracts are adsorbed on the MS surface and form a protective layer that separates the metal from the corrosive solution.

Synergistic performance evaluation of copper–WC-graphene composites: Microstructure, mechanical properties, corrosion, and wear behavior under microwave sintering

This study investigates the synergistic performance of copper–WC–graphene composites fabricated using microwave sintering. Optical Microstructure analysis demonstrated a uniform distribution of reinforcing elements (WC and graphene) within the copper matrix across various compositions (Cu - 5 wt % WC, Cu - 5 wt % WC – 2.5 wt % Graphene, Cu - 5 wt % WC – 5 wt % Graphene, Cu - 5 wt % WC – 7.5 wt % Graphene). The SEM images further revealed controlled porosity and crack-free surfaces. Interfacial bond strength among WC, graphene, and copper was evidenced through SEM and wettability results, affirming successful phase integration. Mechanical property assessments unveiled substantial improvements in compressive strength (31.76%) and hardness (67.21%) after incorporating 5 wt % WC and 7.5 wt % graphene. Corrosion resistance was affirmed through minimal weight loss (0.201 mg) in a 3.5 wt % NaCl solution over 120 h. Wear tests exhibited a noteworthy 81.25% reduction in wear rate for Cu - 5 wt % WC – 7.5 wt % Graphene, emphasizing enhanced wear resistance. The coefficient of friction is determined to be 0.265. XRD analysis validates the composite's composition, featuring copper, copper oxide, copper carbide, tungsten carbide, and carbon phases.

Effect of Yttria-Stabilized Zirconia addition along with Cu in development of titanium based metal matrix composite via FSP technique for the application in biomedical devices

ABSTRACT The present study investigated the effect of incorporating Yttria-Stabilized Zirconia (YSZ) and copper (Cu) in the development of Titanium-Based Metal Matrix Composites (TMCs) using the Friction Stir Processing (FSP) technique. The macrostructure of the TMCs, after adding 5% YSZ and 2% Cu, displayed a defect-free, crack-free, and porosity-free surface, indicating the precision of the FSP method. Microstructure analysis revealed a uniform distribution of reinforcement particles and proper dispersion of grains, key for enhancing mechanical properties. The interfacial bonding between titanium and YSZ was exceptionally strong, devoid of cracks and porosity, attributed to the copper additive’s role. The increase in the number of grains per square inch for the Ti/5% YSZ/2% Cu composite (1176.26 grains per square inch at 500×) signified finer grain structure, contributing to a remarkable 48.04% improvement in tensile strength compared to pure titanium. The uniform distribution of reinforcement and strong bonding between titanium and YSZ are the driving forces behind the 46.34% increased in hardness. Additionally, the wear resistance of the composite improved by approximately 76.66%, a vital characteristic for applications facing abrasive conditions. The corrosion testing demonstrated an 8.33% enhancement in corrosion resistance with the Ti/5% YSZ/2% Cu composite.

The behaviour of AZ91 magnesium-based alloy with Ni–Al2O3 reinforcement

This study focused on fortifying the AZ91 magnesium-based alloy with Ni–Al2O3 particles using the friction stir process. The resultant AZ91–Ni–Al2O3 composite exhibited a crack-free surface with uniform distribution, showcasing strong interfacial bonding. At 500× magnification, the composite displayed 3213.65 grains per square inch. It demonstrated a 51.75% increase in tensile strength and a 45.76% rise in hardness. The introduction of 2 wt-% Ni–5 wt-% Al2O3 led to a remarkable 76.92% reduction in the wear rate. The composite exhibited a coefficient of friction measuring 0.312. X-ray diffraction (XRD) analysis confirmed the presence of Mg, Mg2Al3, Ni and Al2O3. AZ91/5 wt-% Al2O3/2 wt-% Ni composite finds utility in diverse industries in manufacturing components for aerospace, automotive and structural applications.

Determination of total crack free surface area creation and failure in quasi-brittle microcracking solids using 2D GraFEA simulations

One of the long-standing problems in continuum damage mechanics is accurate prediction of damage evolution that accounts for the distribution of microstructural features. This is particularly true for microcracking solids, such as concrete, where non-uniformity in the size and spatial distribution of defects can lead to non-uniqueness in the continuum-averaged energy release rate (and free surface area creation) for cases where local microcrack growth occurs. In this work, a novel theoretical framework for quantifying the crack free surface area creation is formulated and used along with a previously developed non-local numerical technique known as Graph-based Finite Element Analysis (GraFEA). Using the 2D GraFEA approach and its implementation into a finite element code, the invariance of the crack free surface area created and the total amount of energy dissipated due to fracture was demonstrated. This research aims to honor the lifelong accomplishments of Professor Alan Needleman in computational modeling of deformation and fracture.

The role of silica on the superiority of corrosion barrier performance and biological properties of sintered titania-silica composite coating electrophoretically deposited on 316L stainless steel

TiO2 and TiO2–SiO2 composite coatings were electrophoretically deposited on anodized 316L stainless steel substrates and then sintered at 1100 °C. TiO2 coating showed a rutile phase composition involving a cracked surface with a wide diffusion region rich in chromium element near the substrate. While TiO2–SiO2 composite coating showed a crack-free surface with an anatase phase comprising a continuous interlayer. Formation of the dense interlayer prevented the diffusion of substrate elements toward the coating during the sintering and thus inhibited the formation of diffusion region. According to the EIS study after 1 day of immersion in PBS solution, the highest barrier performance belonged to TiO2–SiO2 composite coating where its total faradic resistance (84 MΩ cm2) was 1500 times higher than TiO2 coating and 5.6 times higher than the anodized substrate. This was related to the crack-free surface and the interlayer formed in the composite coating owing to the improving effects of silica. After 28 days of immersion, the total faradic resistance of the TiO2–SiO2 composite coating remained significantly higher (order of 106–107 Ω cm2) than TiO2 coating (∼104 Ω cm2). Furthermore, TiO2–SiO2 composite coating enhanced the apatite formation compared to TiO2 coating or anodized substrate during immersion in SBF solution.

Development of Magnesium Aluminate (MgAl2O4) Nanoparticles for refractory crucible application.

Ceramics are the oxides of metals and nonmetals with excellent compressive strength. Ceramics usually exhibit inert behavior at high temperatures. Magnesium aluminate (MgAl2O4), a member of the ceramic family, possesses a high working temperature up to 2000°C, low thermal conductivity, high strength even at elevated temperatures, and good corrosion resistance. Moreover, Magnesium Aluminate Nanoparticles (MANPs) can be used in the making of refractory crucible applications. This study focuses on the thermal behavior of Magnesium Aluminate Nanoparticles (MANPs) and their application in the making of refractory crucibles. The molten salt method is used to obtain MANPs. The presence of MANPs is seen by XRD peaks ranging from 66° to 67°. The determination of the smallest crystallite size of the sample is achieved by utilizing the Scherrer formula and is found to be 15.3 nm. The SEM micrographs provided further information, indicating an average particle size of 91.2 nm. At 600°C, DSC curves show that only 0.05 W/g heat flows into the material, and the TGA curve shows only 3% weight loss, which is prominent for thermal insulation applications. To investigate the thermal properties, crucibles of pure MANPs and the different compositions of MANPs and pure alumina are prepared. During the sintering, cracks appear on the crucible of pure magnesium aluminate. To explore the reason for crack development, tablets of MgAl2O4 are made and sintered at 1150°C. Ceramography shows the crack-free surfaces of all the tablets. Results confirm the thermal stability of MANPs at high temperatures and their suitability for melting crucible applications.

Impact of selenization with NaCl treatment on the physical properties and solar cell performance of crack-free Cu(In,Ga)Se2 microcrystal absorbers.

In this study, we developed an ink using hexanethiol and Cu(In,Ga)Se2 microcrystals (CIGSe MCs) to make thin films via doctor blade coating. Besides, crack-free thin films were obtained by optimizing CIGSe MC powder concentration and annealing temperature. Subsequently, single-step selenization was performed with and without sodium chloride (NaCl) surface treatment by carefully tuning the temperature. A crack-free surface with densely packed grains was obtained at 500 °C after NaCl treatment. Moreover, the structural parameters of the thin film (annealed at 350 °C) were significantly modified via selenization with NaCl at 500 °C. For instance, the FWHM of the prominent (112) plane reduced from 1.44° to 0.47°, the dislocation density minimized from 13.10 to 1.40 × 1015 lines per m2, and the microstrain decreased from 4.14 to 1.35 × 10-3. Remarkably, these thin films exhibited a high mobility of 26.7 cm2 V-1 s-1 and a low resistivity of 0.03 Ω cm. As a proof of concept, solar cells were engineered with a device structure of SLG/Mo/CIGSe/CdS/i-ZnO/Al-ZnO/Ag, wherein a power conversion efficiency (PCE) of 5.74% was achieved with exceptional reproducibility. Consequently, the outcomes of this investigation revealed the impact of selenization temperature and NaCl treatment on the physical properties and PCE of hexanethiol-based crack-free CIGSe MC ink-coated absorbers, providing new insights into the groundwork of cost-effective solar cells.

Surface and Electrical Characterization of Non-Stoichiometric Semiconducting Thin-Film Coatings Based on Ti-Co Mixed Oxides Obtained by Gas Impulse Magnetron Sputtering

This article presents a detailed investigation of non-stoichiometric (Ti,Co)Ox thin films prepared using the Gas Impulse Magnetron Sputtering (GIMS) technique. The films were prepared with various Co contents (3 at.%, 19 at.%, 44 at.%, and 60 at.%) and characterized for their material composition, microstructure, and electrical properties. The films exhibited an ohmic behavior with linear current-voltage (I-V) characteristics, and their resistivity values ranged from approximately 10−3 to 104 Ω·cm. The highest resistivity was observed in the film with 3 at.% Co content. Thermoelectric measurements revealed that all of the prepared films displayed n-type semiconducting properties, with the Seebeck coefficient (S) tending close to zero. The resistivity of the films decreased as the temperature increased, affirming their semiconducting nature. The activation energy (Ea) values, determined using the Arrhenius formula, ranged from 0.0058 eV to 0.267 eV, with the highest Ea observed for films containing 3 at.% Co. Additionally, the films’ surface topography and microstructure were examined through Atomic Force Microscopy (AFM) and optical profiler techniques. The results showed that the films had smooth, crack-free surfaces with remarkable homogeneity. The surface diversification decreased with the increase in cobalt in the (Ti,Co)Ox films.

Investigating surface integrity, corrosion resistance and biocompatibility of 316L steel using carbon nanotube-assisted EDM process

316L steel employed in biomedical applications has experienced mechanical failure triggered by insufficient biological reactions, a high corrosion rate, and surface impurities. Furthermore, the attenuated surface induced by corrosion and wear releases toxic elements, causing inflammatory effects. The prime aim of this research is to evaluate the carbon nanotube (CNT) based coating for enhancing surface integrity, corrosion resistance, and biological responses. This research also aims to comprehend the relationship between electric discharge machining (EDM) process variables and material properties. Several characterisation techniques, including scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), atomic force microscope (AFM), electron dispersive X-ray (EDX), MTT assays, powder X-ray diffraction (XRD) and potentiodynamic polarisation are utilised. The addition of CNT forms a nanoporous and thin coating of 10.3 μm, resulting in a crack-free surface with an adhesion strength of 23.77 MPa. A low corrosion rate (0.0012 mm/year) and almost 85 % of alive cells are observed on the coated surface of 316L steel. This research shows a method to form carbide and oxide-based coating for biomedical applications.

Highly Conducting Sc and Y co-doped Zirconia Solid Electrolyte Thin Films Prepared via Pulsed Laser Deposition for Solid Oxide Electrochemical Cells Applications

Scandium (Sc) and yttrium (Y) co-doped ZrO2 thin films were fabricated via pulsed laser deposition (PLD). The target material, 4 mol% Sc2O3 and 4 mol% Y2O3 co-doped ZrO2 (ScYSZ), was first synthesized via a solid-state reaction. The ScYSZ thin film was deposited on SiO2-Si substrate by laser ablation, using a Q-switched Nd3+:YAG laser (λ = 266 nm) and substrate temperatures of 600 and 800 oC. Micro-structural and conductivity properties of the resulting as-deposited thin films were investigated. X-ray diffraction (XRD) sample patterns revealed that the as-deposited polycrystalline films can be indexed to a cubic structure. In addition, varying the oxygen partial pressures during the deposition was studied. FE-SEM images revealed dense and crack-free surface morphologies achieved at lower oxygen partial pressures (0.01 Pa and 0.1 Pa) and rough surface with porous morphology at high oxygen partial pressures (1.0 Pa and 10 Pa). The thickness of the film is about 120 nm for the thin film deposited at 800 oC substrate temperature (TS). The total conductivity of the thin film was measured using electrochemical impedance spectroscopy (EIS). Interestingly, the calculated total conductivity of the deposited ScYSZ thin film, 0.1 Pa and TS at 800 oC, revealed about 2.8x10-1 S/cmat 700 oC and with activation energy (Ea) of 0.78 eV from 500 oC to 700 oC. The fabricated as-deposited ScYSZ thin film is one of the highest reported highly conducting solid electrolytes that is a promising material for fuel cell or electrolysis cell applications.