Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

Electron beam melting (EBM) is an additive manufacturing technique, which allows forming customized implants that perfectly fit the loss of the anatomical structure of bone. Implantation efficiency depends not only on the implant’s functional or mechanical properties but also on its surface properties, which are of great importance with regard to such biological processes as bone regeneration or microbial contamination. This work presents the impact of surface modifications (mechanical polishing, sandblasting, and acid-polishing) of EBM-produced Ti6Al4V ELI implants on essential biological parameters. These include wettability, cytotoxicity toward fibroblast and osteoblast cell line, and ability to form biofilm by Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. Obtained results indicated that all prepared surfaces exhibited hydrophilic character and the highest changes of wettability were obtained by chemical modification. All implants displayed no cytotoxicity against osteoblast and fibroblast cell lines regardless of the modification type. In turn, the quantitative microbiological tests and visualization of microbial biofilm by means of electron microscopy showed that type of implant’s modification correlated with the species-specific ability of microbes to form biofilm on it. Thus, the results of the presented study confirm the relationship between such technological aspects as surface modification and biological properties. The provided data are useful with regard to applications of the EBM technology and present a significant step towards personalized, customized implantology practice.

This study presents an analysis of the impact of the oxide layers, prepared utilizing fiber laser radiation (1062 nm) in ambient air with different process parameters, on the corrosion resistance of EN 5754 aluminum alloy. Due to both high corrosion resistance and high fatigue strength, a 5754 alloy is used, among others, in the marine, aerospace, automotive, and chemical industries. Nevertheless, it corrodes in aggressive environments (with high chloride ions concentration). The controlled delivery of laser radiation energy in the oxygen environment allows the formation of the oxide layer on the surface of the material. We have determined that it significantly affects the resistance of these materials to corrosion. As a result of laser irradiation, changes in the chemical structure of the surface layer (chemical composition as well as surface development) can be observed. It may exert both a positive and a negative consequence on the corrosion resistance. The electrochemical corrosion tests (potentiodynamic polarization and electrochemical impedance spectroscopy EIS) have been carried out in an aggressive environment (3% NaCl). Moreover, microscopic examination, chemical tests, and roughness were also performed. The study revealed that appropriate control of the laser process can significantly increase the original corrosion resistance of the 5754 aluminum alloy.

This paper presents the result of the investigation of organically modified silica (ORMOSIL)-zirconia coatings used to enhance their protective properties, namely corrosion and scratch resistance. Two different materials, i.e., SiO₂/ZrO₂ and SiO₂/GPTMS/ZrO₂, were synthesized, measured, and analyzed to find the difference in the used organosilane precursor (dimethyldiethoxysilane and (3-glycidoxypropyl)trimethoxysilane, respectively). SiO₂/ZrO₂ coatings showed higher hardness than SiO₂/GPTMS/ZrO₂. Moreover, the value of polarization resistance (R_p) for SiO₂/GPTMS/ZrO₂ coated 316L steel relative to the uncoated one was obtained. It was nearly 84 times higher. The coating delamination was observed with load 16N. Additionally, the corrosion mitigation for 316L coated by SiO₂/GPTMS/ZrO₂ was observed even after extended exposure to corrosion agents.