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.
