Sol-gel derived calcium hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂; CHA) thin films were deposited on stainless steel substrates with transverse and longitudinal patterned roughness employing a spin-coating technique. Each layer in the preparation of CHA multilayers was separately annealed at 850 °C in air. Fabricated CHA coatings were placed in simulated body fluid (SBF) for 2, 3, and 4 weeks and investigated after withdrawal. For the evaluation of obtained and treated with SBF coatings, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray diffraction (XRD) analysis, Raman spectroscopy, XPS spectroscopy, scanning electron microscopy (SEM) analysis, and contact angle measurements were used. The tribological properties of the CHA coatings were also investigated in this study.

Aluminum (Al) components of high quality often require an optimal ratio of lightness and favorable mechanical properties. In order to improve the physical-mechanical properties of Al, an aluminum oxide (Al₂O₃) film is usually formed on the surface of Al, which itself is characterized by high strength, hardness, corrosion resistance, and other technical properties. Unfortunately, depending on the conditions, the oxide film may be formed from different crystal phases on the Al surface, which are not always of desirable quality, i.e., the α-Al₂O₃ phase. The present review demonstrates that the properties of the Al₂O₃ film may be improved by Al processing with a laser beam according to the scheme: Al (Al alloy) → electrochemical anodizing → treatment with laser irradiation → α-Al₂O₃. Both Al substrate and the anodizing electrolyte affect the phase transformation of anodic Al₂O₃. Laser irradiation of the Al₂O₃ surface leads to high heating and cooling rates, which may promote the formation of a highly crystalline α-Al₂O₃ phase on anodic Al₂O₃.

Recent advances in ceramic materials, particularly porous alumina (Al₂O₃), have significantly enhanced the safety and efficacy of medical implants by improving biocompatibility and modulating cellular behavior for biomedical applications. Variations in the surface structure and chemical composition of porous Al₂O₃ promote different biological responses and coating stability, underscoring the need for further biological and corrosion research. Traditional methods for producing alumina ceramics from powder are expensive, time-consuming, and limited in their ability to create complex shapes and large structures due to the brittleness of alumina. This study evaluates the biocompatibility of bioceramic-coated aluminum (Al) alloy 6082 as a lightweight and cost-effective alternative for bone osteosynthesis plates. Al₂O₃ coatings were achieved through anodization using phosphoric and sulfuric acids. The untreated and anodized alloys were analyzed for chemical stability and biocompatibility and compared with medical-grade titanium alloy. All specimens exhibited excellent biocompatibility, demonstrating high adhesion and viability of the fibroblast cell line. Corrosion resistance and metal ion release were assessed in simulated body fluid, with all specimens effectively suppressing the release of Fe and toxic Al ions. The untreated Al alloy exhibited a higher release of Mn ions than the coated specimens. Notably, the bioceramic coating obtained in sulfuric acid demonstrated 3 orders of magnitude higher corrosion resistance, indicating its potential suitability for biomedical applications. By addressing the limitations of traditional alumina ceramics, our approach enables the fabrication of products in diverse sizes and shapes, offering a practical solution for creating customized biomedical implants.

The adhesion quality of Ni-P coatings on aluminum is important for mechanical and anticorrosion properties. In this study, the adhesion of Ni-P coatings on nanoporous Al₂O₃ ceramic (NAC) was evaluated by impact testing. NAC was fabricated on AA6061 alloy by anodizing in sulfuric acid. The deposition of Ni-P coating was carried out on NAC with and without zincate pretreatment. It was found that zincate activation of Al₂O₃ accelerates the formation of Ni-P coating. A cross-sectional analysis using energy-dispersive X-ray spectroscopy showed that the mechanical properties and impact resistance of the Ni-P coating are strongly related to the chemical composition in the vicinity of its interface with Al₂O₃. The course of the formation process of Ni-P coating and its mechanisms are also very important. Although the formation of Ni-P coating was slower without zincate treatment, its stronger adhesion to NAC led to superior impact resistance compared to zincate-treated Al₂O₃. Improved durability of items with Ni-P coatings can benefit many applications.