This study investigates Fe-TiC composites containing titanium carbide (TiC) reinforcement at various weight ratios, produced via powder metallurgy. The effects of TiC content on ultrasonic wave velocities (VL, VS), elastic moduli (L, G, K, E), density (rho), Poisson's ratio (mu), acoustic impedance (Z), microhardness, porosity, and grain size were evaluated using ultrasonic testing (UT). Results showed that increasing TiC content improved density, stiffness, and acoustic impedance, while reducing porosity and Poisson's ratio. The Fe-TiC-5 composite exhibited the best combination of properties. The slight negative Poisson's ratio (-0.080) was attributed to local microstructural effects and ultrasonic measurement uncertainty, not true auxetic behavior. The acoustic impedance range (0.027-0.034 MRayl) suggests suitability for acoustic coupling and nondestructive testing applications.
Here, the physical, mechanical, wear, optical, and microstructural properties of sanitaryware glazes doped with gehlenite (Ca2Al2SiO7) crystals were investigated systematically. A two-stage sintering was first used to produce a single-phase Ca2Al2SiO7 from eggshells. Powder gehlenite (pGh) was then incorporated into the reference glaze (R0) at 1, 3, 5, and 7 wt.%. All designed glazes were applied to a sanitaryware body and sintered as a single firing. Based on the X-ray diffraction (XRD) results, the R0 glaze comprised zircon (ZrSiO4), quartz (SiO2), and amorphous phases. Ca2Al2SiO7, together with these phases, was observed in pGh-added glazes. Considering the scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses, the R0 glaze also contained dendritically grown diopside (CaMgSi2O6) crystals. In contrast, R7 (doped with 7 wt.% pGh) glaze included interlocking and elongated Ca2Al2SiO7 crystals. Doping pGh to R0 glaze increased the % water absorption and decreased the bulk density and Vickers hardness values. Compared to the R0, the R7 glaze exhibited 30.95% higher flexural strength, increased whiteness (L=90.39), visually indistinguishable color differences (Delta E=2.27), and a high wear grade (Class 3). The Ca2Al2SiO7 crystals derived from eggshells could be used as a strength-enhancing, opacifying external additive without deteriorating the final properties of sanitaryware glazes.
Hydroxyapatite (HA) derived from catfish bone was successfully coated onto Ti-6Al-4V alloy using the Plasma Electrolytic Oxidation (PEO) method. The coating process was carried out in a strong alkaline electrolyte solution with treatment durations of 10, 20, and 30 minutes (Ti/HA-10, Ti/HA-20, and Ti/HA-30). The coated Ti-6Al-4V samples were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and compressive strength testing. Ti/HA-10 sample exhibited the highest crystallinity, while Ti/HA-10 and Ti/HA-20 showed more homogeneous pore structures with porosity exceeding 60% and thicker oxide layers than Ti/HA-30. The study found that the 30-minute duration was less effective due to the increased electrical resistance of the oxide layer, which hindered HA deposition efficiency and reduced coating thickness. While compressive strengths were below 200 MPa and Young's modulus values (2.6-3.6 GPa) were lower than typical cortical bone, these properties are beneficial for reducing the stress-shielding effect. These findings suggest the potential of HA-coated Ti-6Al-4V for biomedical use.
We developed a stable and scalable strategy for fabricating alumina microspheres by integrating UV-assisted microfluidic droplet templating with a poly(ethylene glycol) diacrylate-pseudoboehmite (PEGDA-PB) hybrid formulation. PEGDA served as a photocurable framework that rapidly formed a three-dimensional network upon UV exposure, immediately immobilizing PB particles and preventing microspheres deformation and collapse during subsequent processing. Using an optimized formulation (10% v/v PEGDA and 15% w/v PB), we produced alumina microspheres in the 100 similar to 300 mu m range with high sphericity, narrow size distribution after calcination. The same formulation was directly extended to large spheres (>700 mu m), which maintained shape fidelity and structural uniformity and exhibited an average crushing strength of 40.39 N without binders or pressure compaction. Mercury intrusion porosimetry confirmed a well-developed porous structure with high accessible porosity, supporting the formation of transport channels and mechanically stable frameworks after calcination. SEM analysis further revealed porous and crack-free structures of alumina microspheres, demonstrating that the sacrificial PEGDA network enables defect-free solidification during calcination. To our knowledge, the use of PEGDA for alumina microsphere fabrication has not been reported previously. This method provides precise size control, high purity, and strong mechanical performance across a broad particle size range, offering a practical route for producing alumina microspheres suitable for catalysis, adsorption, and ceramic support applications.
Porcelain stoneware tiles are widely used in architectural applications due to their low water absorption, high mechanical strength, and standardized durability performance. This work investigates the effect of engineered surface pattern geometries on the durability of porcelain stoneware tiles, using tests aligned with ISO 10545 standards. Industrially representative tile compositions were uniaxially pressed, fired at high temperature, and patterned with linear micro-ridges (PRP) and orthogonal micro-grids (PGP) to maintain consistent surface relief after sintering. Water absorption measurements confirmed porcelain-grade densification. Surface durability was evaluated through deep abrasion resistance and scratch hardness tests, while thermal shock resistance was assessed via residual flexural strength. Results revealed that surface pattern geometry significantly affects mechanical performance: cumulative deep abrasion volumes decreased from 77 mm3 for untextured reference tiles (URT) to 60 mm3 for PRP and 55 mm3 for PGP, representing reductions of 22% and 28.6%, respectively. Scratch resistance testing showed that PGP tiles exhibited a saturation-like response at high loads (>= 6 N), with scratch depth limited to similar to 19.5 mu m, whereas URT reached similar to 25 mu m. Thermal shock testing indicated enhanced performance of patterned tiles, with PGP retaining similar to 41 MPa residual strength after 30 cycles compared with 24 MPa for URT. Mechanistically, micro-patterns redistribute surface stresses, reduce localized micro-chipping, and constrain crack propagation, leading to lower wear rates and improved thermal shock tolerance. Importantly, patterning did not compromise water absorption or bulk vitrification. These findings demonstrate that carefully engineered surface patterns can enhance the durability of porcelain stoneware tiles while maintaining compliance with ISO 10545 requirements, offering a practical strategy to integrate aesthetic design with high-performance functional properties.
The calcination of a kaolin clay at 700-1000 degrees C for various times and its influences on the microstructure and strength of metakaolin phosphate-activated geopolymers (MKPGs) were investigated. The results indicated that the residual water and the structural evolution in metakaolin affected the geopolymerization of MKPGs. The ranges of the calcining processes could be divided into three parts based on the activity of the metakaolin, namely: a pre-active range, active range, and lost-activity range. There was a critical value of c. 8.0% for the residual water, beyond which, the metakaolin could not be activated by phosphoric acid solution. As the calcination temperature or the holding time increased, the residual water content decreased gradually, and the metakaolin could be activated. However, when the kaolin was calcined at 950 degrees C for more than 60 min, or 1000 degrees C for more than 25 min, corresponding to the precipitation of mullite in the kaolin, geopolymerization was not induced, and the slurry of MKPGs could not be hardened.
The demand for lightweight and high-strength materials in modern bicycle frames has driven the development of advanced nano-reinforced composite systems. This study investigates the structural and mechanical performance of carbon fiber/ epoxy hybrid composites reinforced with Hexagonal Boron Nitride (h-BN) particles. In this work, h-BN nanoplatelets are incorporated into the epoxy matrix of Carbon Fiber Reinforced Polymer laminates to improve interfacial bonding, mechanical stability, and load transfer within the composite structure. The hybrid nanocomposite is designed to utilize the high modulus, thermal stability, and chemical resistance of h-BN to enhance the overall performance of the composite system. The results show that the addition of h-BN nanoparticles improves the stiffness and structural stability of the composite while reducing stress concentration and deformation under applied loads. Improved interfacial interactions between the nanofiller, epoxy matrix, and carbon fibers contribute to more efficient load transfer and better mechanical performance. Overall, the findings suggest that h-BN reinforced carbon fiber/epoxy hybrid nanocomposites have strong potential as lightweight and durable materials for next-generation bicycle frame structures requiring improved mechanical reliability and structural efficiency.
This paper investigates the grinding mechanism and optimization of process parameters for spherical surfaces in silicon nitride joint bearings to enhance their grinding precision and efficiency. First, the effects of grinding wheel speed, workpiece speed, feed depth, and abrasive size on surface roughness, material removal rate, and equivalent grinding depth are analyzed based on the abrasive grain trajectory and material removal mechanism. Subsequently, a quadratic function model for the spherical surface grinding evaluation parameters is established using the response surface methodology. Finally, an improved multi-objective particle swarm optimization model is established, incorporating a process constrained discrete sampling strategy for grinding parameters to achieve precise and efficient grinding of spherical surfaces under multi-pass conditions. Experimental results demonstrate that the developed response surface model exhibits high predictive accuracy, with errors for surface roughness, material removal rate, and equivalent grinding depth below 0.0176 mu m, 0.3615 mm3/min, and 3.8 mu m, respectively. The grinding efficiency for the spherical surfaces was increased by 21.22% following the parameters optimization. The results provide a theoretical basis and a practical strategy for the actual grinding process.
Perovskite-type LaFeO3 based oxides are promising electrode materials for Solid oxide fuel cells functioning at intermediate temperatures because of their high thermal stability and mixed ionic and electronic conductivity. In this study, LaFeO3 and LaFe0.9Ti0.1O3 were prepared via sol-gel method to improve compositional uniformity and control the microstructure. The sol-gel process allowed for a uniform distribution of Ti within the LaFeO3 lattice. X-ray diffraction analysis confirms the formation of a phase pure cubic perovskite structure with no detectable secondary phases. Systematic peak shifts indicated successful Ti substitution at the Fe-site. The structural changes suggest lattice distortion and a shift in the defect chemistry. SEM analysis revealed densely packed polycrystalline grains with improved intergranular connectivity due to Ti doping. We observed reduced porosity and improved densification in the doped samples. The TEM images revealed irregular nano crystalline particles with varying grain sizes. The SAED patterns confirmed the polycrystalline nature and maintained the crystallinity of the cubic phase. The microstructural changes indicated improved grain growth and lower grain boundary density. These features help to reduce the grain boundary resistance. Electrical conductivity measurements revealed thermally activated transport behavior. The conduction mechanism follows the small polaron hopping model. An enhancement in electrical conductivity is observed increasing from 0.1509 S. cm-1 for LaFeO3 to 0.1819 S. cm-1 for LaFe0.9Ti0.1O3. This increase in performance can be credited to the shift in the ratio of Fe3+/Fe4+ and the optimal levels of oxygen vacancies. Improved grain connectivity leads to improved conductivity. The cubic perovskite structure was found to be stable even when Ti was added.
Manufacturers in a variety of industries are constantly striving to create structures that are lighter, stronger, good corrosion resistance and other required features better than traditional materials. All of these manufacturers need, can be fulfilled with composite materials. Composites are multi-material structures made up of a range of polymers, metals and ceramics. The specimens are manufactured by Ultrasonic Stir Casting Process by using Al 8090 as a base metal and SiC as reinforcement. ZrO2 and TiO2 are added as hybrid materials. After fabrication of samples, Tensile, Impact and fatigue tests are performed to compute mechanical properties like Tensile strength, Impact strength, fatigue, finally a comparison is done between the mechanical properties of base Al8090 alloy and the fabricated aluminum metal matrix hybrid composites. A larger spectrum of physical, dynamical, and mechanical testing is required to meet ever-increasing performance standards in industries such as aircraft, aerospace, battery, and environmentally sustainable-energy systems.
A full factorial design was employed to evaluate the effects of various preparation conditions for sanitary ware slips. We investigated the relationships between processing conditions, microstructure, and final properties. The results revealed that casting rate, bulk density, and the modulus of rupture of the cast body were all influenced by the preparation conditions. Variations in rheology and the presence of dissolved ions in the mixing water explained the statistically significant effects of the preparation variables, including water temperature, mixing time, water quality, and aging. Preparation variables that increased the thixotropy of the slip promoted the development of a highly porous structure in the cast body, leading to increased casting rate and reduced green bulk density and modulus of rupture. These changes additionally affected the final properties by increasing porosity and reducing the fired modulus of rupture. Based on the findings, we propose optimal conditions for preparing sanitary ware slips while minimizing unnecessary energy consumption.
In this study, monodisperse spherical Fe3O4 magnetic particles were successfully synthesized via a one-step solvothermal method using Fe(NO3)3 & centerdot;9H2O as the iron source, TEA as a mild alkali source, 1,3-PDO as both solvent and reducing agent, and PEG-1500 as a surfactant. The effects of water content and PEG-1500 dosage on the morphology, particle size distribution, and phase composition of the products were systematically investigated. The results indicated that the crystalline water in Fe(NO3)3 & centerdot;9H2O (5 v/v%) promotes the slow and homogeneous hydrolysis of Fe3+, which improves crystallinity and optimizes particle size distribution. Excessive water addition, however, accelerates nucleation, broadens the particle size distribution, and leads to particle agglomeration. Although the addition of PEG-1500 does not alter the crystal structure, it significantly enhances particle dispersibility through steric hindrance effects. The optimal monodispersity was achieved with 1.2 g of PEG-1500, yielding spherical Fe3O4 particles with an average diameter of approximately 264 nm. The as-prepared Fe3O4 particles exhibit good crystallinity, typical soft magnetic properties, a saturation magnetization of up to 80.19 emu & centerdot;g-1, and a hydroxyl-rich surface. Based on these findings, a formation mechanism involving "ionization-reduction-hydrolysis-dehydration-nucleation-growth-crystallization" processes is proposed. This work provides an effective strategy and theoretical foundation for the controllable synthesis of high-performance monodisperse Fe3O4 magnetic particles.
The present study systematically investigates the effects of pentavalent cation doping (M5+ =Nb, Ta, V) on the slag corrosion resistance of calcium hexaaluminate (CA6), with particular emphasis on the evolution of microstructural and physical properties. The incorporation of Nb5+and Ta5+was found to significantly mitigate the dissolution of CA6 in molten slag. This improvement is primarily due to the formation of a dense composite layer of MgAl2O4 (MA) and CaAl4O7 (CA2), which effectively acts as a barrier against further slag penetration and corrosion. The enhanced performance is attributed to the optimized physical properties and decrease of wettability. In contrast, V5+doping resulted in deteriorated performance, manifesting as deeper slag corrosion, which is associated with increased porosity and reduced density. These findings underscore the critical roles of apparent porosity, bulk density, and mechanical strength in determining the slag corrosion behavior of CA6-based materials. Consequently, strategic selection of high-valence cation additives presents a promising route for enhancing the overall slag resistance of CA6 refractories.
Bone implants are urgently required to restore structural integrity and functionality in patients with fractures, trauma, or degenerative bone disorders, especially in light of the rising global prevalence of bone-related injuries. This study developed polyetheretherketone (PEEK) composites with hydroxyapatite (HA) derived from pearl shells for bone implant applications. HA was synthesized via precipitation and mechanically mixed with PEEK at concentrations of 0, 10, 20, 35, and 50% w/w. Characterization using X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), and microhardness testing was performed. XRD analysis confirmed the presence of both PEEK and HA crystalline phases, with crystallinity increasing from 63.9% to 70.8% with HA addition. FTIR spectroscopy further verified the composite's composition by identifying characteristic functional groups of both PEEK and HA (PO43-), indicating a stable physical mixture. SEM analysis revealed that higher HA content created a denser surface, reducing porosity from 46.8% to 33.1% and pore size from 80.5 to 57.5 nm. Consequently, microhardness improved from 29.3 to 35.2 HV. The PEEK/HA10 composite demonstrated the optimal balance of properties, aligning with bone-implant standards.
Electrochemical discharge machining (ECDM) is a micromachining process involving brittle, electrically, conductive, and non-conductive materials. The interrelationship of the parameters has made it difficult to determine an ideal parametric combination for micro drilling in high-carbon steel. In this investigation, a Royal Enfield bike chain link made of CRC high-carbon steel was used as a specimen to make a micro drill using electrochemical discharge machining, with sodium hydroxide as the electrolyte. An indigenously developed electrochemical discharge turning (ECDT) setup was used in this experimental work. During ECDM, the impacts of different process factors such as voltage, electrolyte concentration, and duty cycle are analyzed. The maximum material removal occurs at 90v and 20g of electrolyte concentration. Maximum material removal takes place with duty cycles of 40 and 50%. The surface characteristics of the machined specimens were determined using a scanning electron microscope, and the size of the micro drill was measured. The response surface methodology was used to develop the mathematical models for material removal rate and tool wear.
Metal-organic frameworks (MOFs) are crystalline and porous materials that have emerged as promising candidates for water treatment applications due to their high surface area and tunable pore structures. Zirconium fumarate (Fu-Zr) was synthesized by a precipitation method using formic acid as a coordination modulator and evaluated for fluoride removal from drinking water. The materials, prepared at 60 degrees C, 70 degrees C, and 100 degrees C, were characterized by nitrogen physisorption, X-ray diffraction (XRD), thermogravimetric analysis (TGA-DTA), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). All samples exhibited a microporous crystalline structure with type I adsorption-desorption isotherms. The sample synthesized at 70 degrees C showed the highest BET surface area (730 m2 g-1), whereas the material synthesized at 100 degrees C exhibited enhanced surface chemical accessibility. Batch adsorption experiments showed that Fu-Zr synthesized at 100 degrees C exhibited the highest fluoride removal efficiency (87%) and a maximum adsorption capacity of 238 mg g-1 at 30 degrees C. Equilibrium data were better described by the Freundlich isotherm, indicating adsorption on a heterogeneous surface, whereas kinetic studies followed a pseudo-second-order model, suggesting surface-controlled interactions. Fluoride removal remained effective over a wide pH range (4-10), and fluoride concentrations were reduced below drinking water limits under optimized conditions. Thermodynamic analysis confirmed that fluoride adsorption onto Fu-Zr is spontaneous, with optimal performance at moderate temperatures. These results demonstrate that precipitation-synthesized Fu-Zr, particularly when prepared at 100 degrees C, is a highly effective adsorbent for fluoride-contaminated water, where adsorption is governed primarily by surface chemistry rather than surface area alone.
Etched Ni-Cu-P coatings were fabricated by electroless plating followed by HNO3 etching and used as supercapacitor electrodes. The as-deposited nickel-rich Ni-Cu-P coating presents an amorphous phase, whereas the low-phosphorus copper-rich coating exhibits a polycrystalline phase. The actual Cu/Ni ratio in the coating is higher than that in the plating solution and shows a linear relationship between them. The deposition rate shows an inverse trend with copper sulfate concentration. The specific capacitance of the as-deposited coating slightly increased with higher nickel content. After etching, the coating shows increased nickel and phosphorus contents, accompanied by a reduction in copper content. Coatings with higher copper content show free etching behavior, leading to a smaller increase in specific capacitance. In contrast, the etched coatings with low Cu content show trenches or pores on the surface. The specific capacitance of the coating deposited at a copper sulfate concentration of 2 g L-1 after etching increased from 13.3 to 290 F g-1 at 10 mV s-1. The capacitive contribution of the as-deposited coating increases with increasing scan rate and copper sulfate concentration. After etching, coatings with low Cu content show a transition in the charge storage mechanism from surface-controlled to diffusion-controlled processes.
In order to realize the efficient use of resources of industrial solid waste, this paper investigates the synergistic effect of carbonated steel slag and gold tailings on the mechanical and microstructural properties of composites. Taking the carbonation pressure during carbonation and the mass ratio of steel slag and gold tailing as variables, we systematically studied its effect on the compressive performance by means of compression test, nanoindentation test, XRD, SEM, MIP, etc. When the carbonation pressure was 0.25 MPa, and the mass ratio of steel slag and gold tailing was 7:3, abundant CaCO3 formed, the pore filling and pore size refinement were realized, the compressive strength reached 90.03 MPa, increased by 45.11% compared to that of control specimens (A1). The micropore (<10 nm) content increased, macroporosity (>1000 nm) decreased, specific surface area was maximized (27.09 m(2)/g), average pore diameter was minimized (4.24 nm), and densification due to the filling role of gold tailings, compacting the pore structure, and enhancing mechanical properties. Excessive tailings led to FeS2 oxidation reaction generated gypsum (CaSO4 & centerdot;2H(2)O), causing pore coarsening and damage to the microscopic structure, which reduced mechanical properties. These findings provide insights for sustainable utilization of steel slag and gold tailings in construction materials.
Polished or glazed 4 mol% yttria-partially stabilized zirconia (4Y-PSZ) and lithium disilicate (LD) dental ceramics are of considerable importance for intraoral use, as they have a major impact on the cytocompatibility and antibiofilm resistance. In this study, two glazes were applied-that is, Arte (Hass Co., Ltd., Gangneung, Gangwon State, Republic of Korea) and Insync (Jensen Dental, North Haven, CT, USA). Subsequently, the human gingival fibroblast (HGF-1) response and biofilm formation of polished versus glazed 4Y-PSZ and LD ceramics were evaluated. For the glazed 4Y-PSZ and LD samples, a low bulk density and water contact angle, essential for biological performance, were evident. Moreover, the viability of the HGF-1 cells was greater than 98% in all samples. The highest cell densities were observed on the Arte-glazed 4Y-PSZ and LD ceramics. Conversely, the Arte-glazed 4Y-PSZ and Insync-glazed LD specimens exhibited the lowest biothickness. The Insync-glazed 4Y-PSZ and Arte-glazed LD samples exhibited the lowest biofilm biomass, indicating improved bacterial resistance compared to the polished samples. Although polishing may be clinically useful as it improves the cell response and reduces biofilm formation, glazing exhibited superior efficacy regardless of the glaze type.
This study investigates the effects of potassium (K) and lanthanum (La) co-doping on mesoporous bioactive glass (BG), revealing significant modifications in its structural, thermal, and textural properties. X-ray diffraction patterns demonstrate enhanced crystallinity in K/La-BG, with prominent peaks at 33.6 degrees and 34.2 degrees corresponding to the (024) and (220) crystal planes, respectively. Scanning electron microscopy reveals a transition from a porous network structure in BG to densely packed, irregularly shaped particle aggregates in K/La-BG. Fourier transform infrared spectroscopy highlights changes in the Si-O-Si network (1400 cm(-1)), Si-O bonding (800-1100 cm(-1)), and P-O domain (600-800 cm(-1)) regions upon doping. Thermogravimetric analysis shows improved thermal stability in K/La-BG, with a total weight loss of approximately 80% across the temperature range of 30-714 degrees C. Brunauer-Emmett-Teller analysis reveals a reduction in surface area from 11.54 m(2)/g in BG to 8.23 m(2)/g in K/La-BG, along with decreased pore volume (from 0.025 cc/g to 0.021 cc/g) and pore diameter (from 31.35 & Aring; to 25.15 & Aring;). These findings collectively demonstrate that K and La co-doping significantly alters the physicochemical properties of BG, potentially influencing its dissolution kinetics, bone-bonding capabilities, and overall bioactive performance in bone tissue engineering applications.
