Ceramic oxide coatings were fabricated on 7075 aluminum alloy via micro-arc oxidation (MAO) in a silicate-phosphate electrolyte under voltages of 250 V, 300 V, and 350 V for 600 s. The effect of the applied voltage on the surface morphology, microstructure, phase composition, microhardness, roughness, coating thickness, and corrosion resistance was systematically studied. The coating obtained at 300 V demonstrated a dense structure with relatively low surface roughness (2.3 μm) and a thickness of approximately 70 μm. This sample also exhibited the most balanced performance, combining relatively high microhardness (~422 HV) and the lowest corrosion current density (6.1 × 10⁻⁷ A/cm²) in a 3.5 wt.% NaCl solution. X-ray diffraction patterns revealed the presence of both γ- and α-Al₂O₃ phases in all coated samples, with a relative increase in α-phase intensity observed at an intermediate voltage. The results demonstrate that the applied voltage plays a critical role in determining the coating structure and performance, offering insights into the surface treatment of high-strength aluminum alloys for engineering applications.

This article is dedicated to investigating the impact of different electrolyte compositions on the development of titanium coatings endowed with superior mechanical, tribological, and corrosion properties. An experimental analysis was conducted on three distinct electrolyte formulations, each contributing unique attributes to the coating's structural formation. Advanced analytical techniques, including scanning electron microscopy, hardness testing, wear resistance evaluation, and corrosion trials in harsh environments, were employed to gauge the mechanical, tribological, and anti-corrosive performance of the coatings. The utilization of scanning electron microscopy, X-ray structural analysis, and additional methodologies enabled an in-depth characterization of the microstructure and elucidated the relationship between the physico-mechanical properties and the electrolyte's chemical makeup. Among the electrolytes examined, the composition containing potassium hydroxide emerged as superior, fostering coatings with a distinctively porous structure that augment mechanical attributes. A considerable degree of porosity coupled with relatively small pore dimensions suggests the potential to engineer structures that exhibit optimal mechanical robustness. Furthermore, research findings related to this specific electrolyte composition revealed enhancements in the friction coefficient and wear resistance, indicating its promising prospects for tribological applications. The study also meticulously addressed the corrosion aspects, revealing that the microarc oxidation-derived coatings substantially improve corrosion resistance by offering more favorable potentials and currents than the bare titanium substrate. The efficacy of microarc oxidation as an avant-garde technique to advance the properties of titanium alloys underscores its prospective utility and practical relevance in contemporary industrial applications.

This work is a study aimed at optimizing the process of superarc metallization, with a focus on the effect of stress on the properties of the spraying coatings. In this work, 30HGSA grade steel wire was used for the coating of 45 steel, widely used in mechanical engineering. The use of supersonic...

Titanium and its alloys are widely used in biomedical implants due to their favorable mechanical properties and corrosion resistance; however, their natural surface lacks sufficient bioactivity and antibacterial performance. Micro-arc oxidation is a promising approach to producing bioactive coatings, and the incorporation of nanoparticles such as TiO₂ may further improve their functionality. This study aimed to determine the optimal TiO₂ nanoparticle concentration in the micro-arc oxidation electrolyte that ensures coating stability and biological safety. Calcium–phosphate coatings were fabricated on commercially pure titanium using micro-arc oxidation with two TiO₂ concentrations: 0.5 wt.% (MAO 1) and 1 wt.% (MAO 2). Surface morphology, porosity, and phase composition were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. Corrosion resistance was evaluated via potentiodynamic polarization in NaCl and Ringer’s solutions, while biocompatibility was assessed in vitro using HOS human osteosarcoma cells and MTT assays. Increasing the TiO₂ content to 1% decreased coating porosity (13.7% vs. 26.3% for MAO 1), enhanced corrosion protection, and reduced the friction coefficient compared to bare titanium. However, MAO 2 exhibited high cytotoxicity (81% cell death) and partial structural degradation in the biological medium. MAO 1 maintained integrity and showed no toxic effects (3% cell death). These results suggest that 0.5% TiO₂ is the optimal concentration, providing a balance between corrosion resistance, mechanical stability, and biocompatibility, supporting the development of safer implant coatings.

This study investigates the effects of electron beam irradiation on the mechanical and tribological properties of polyetheretherketone (PEEK), with particular focus on modifications resulting from the application of Litol-24 lubricant. Samples of pre-treated PEEK were irradiated at doses of 100,...

Cold gas dynamic spraying (CGDS) enables the production of protective coatings without melting or oxidation. In this study, Al–Zn–TiO₂ composite powders were prepared by wet agglomeration with binders and by dry mechanical mixing, and deposited onto mild steel substrates. COMSOL simulations of gas dynamics and particle acceleration identified optimal parameters (0.6 MPa, 600 °C, 15 mm, 90°), which were then validated experimentally. Coatings formed under these conditions exhibited dense microstructures, minimal porosity (~0.5%), and continuous, defect-free interfaces with the substrate. SEM and XRD confirmed solid-state bonding without new phase formation. Corrosion tests in 3.5% NaCl revealed a tenfold reduction in corrosion current density compared to bare steel, resulting from synergistic sacrificial (Zn), barrier (Al), and reinforcing/passivating (TiO₂) effects. Tribological tests demonstrated reduced friction (CoF ≈ 0.4–0.5) and wear volume. Compared with reported Al- or Zn-based cold- and thermal-sprayed coatings, the optimized Al–Zn–TiO₂ system shows superior performance, highlighting its potential for industrial anti-corrosion and wear-resistant applications.