Biomaterials are effective alternatives for tissue substitution, including the bone tissue, since they do not pose risks of transmission of diseases or immune rejection. Nowadays, there is an interest in new materials capable of being associated with other substances which favor bone formation, especially natural biopolymers, in particular chitosan, which may present a potential for repairing bone defects and forms films that adhere to metal surfaces. Titanium, despite being a material greatly employed in implants because of its excellent physical properties, does not present bioactive characteristics, making it necessary to use methods of surface modification to enhance its biological response, favoring bone formation. This work aims at studying commercially pure titanium (cp-Ti) coating with chitosan using the biomimetic method and the evaluation of the effects of process variables as substrate surface conditions. Subsequently, the incorporation of AgNO3 was studied and its effects on corrosion resistance were evaluated. To evaluate the coating process, several tests were conducted, such as scanning electron microscopy, X-ray diffraction and infrared spectroscopy. From the results obtained, the efficacy of the chitosan film in inhibiting the corrosion of the metals is concluded, which was the target of this study, thus justifying its use for osseointegration and in several implants.

The development of alternatives for wear protection in surface engineering can be responsible for a significant decrease in energy waste as a large amount of the energy produced in the world is lost due to tribological contact. Dynamic Glancing Angle Deposition has been recently evaluated as a route to produce coatings with improved wear performance. In this technique, the substrate oscillates along with a determined range in front of the sputtering target during the growth of the film. In this study, five oscillatory ranges (0, ±5°, ±10°, ±15°, ±20°) were probed to manufacture nanostructured Cr-Al-N coatings using direct current magnetron sputtering, and their impact was investigated on the grain morphology, phase formation, chemical composition, and performance of the coatings. FEG-SEM revealed the formation of multilayer-like architecture across the grains of the coatings. The deposition rate and hardness improved, and a more than 2-fold decrease in the material loss was observed in a comparison between the stationary-deposited conventional coating and the sample produced under ±10° oscillatory range. This indicated the potential use of this technique in future surface engineering applications.

Mining processes produce a massive amount of waste which, if not treated properly, can cause significant environmental and social impacts. Recently, some studies have focused on the use of mining waste as an alternative raw material. This work developed new sustainable ceramic formulations based on bentonite mining waste (BMW) for applications in porcelain stoneware. The BMW was incorporated into the ceramic masses in different percentages (0, 2.5, 5, 10, 15, 20, 25, and 40 wt.%), in partial replacement to feldspar and total to quartz. X-ray diffraction (XRD), differential thermal calorimetry (DTA), and thermogravimetry analysis (TGA) techniques were used to characterize bentonite waste. Samples (50 mm × 20 mm × 5 mm) were obtained by uniaxial pressing. Such samples were dried and sintered at 1150, 1200, and 1250 °C. The physical–mechanical properties (apparent porosity, water absorption, linear shrinkage, apparent density, and flexural strength) were evaluated for sintered samples. The phases formed after sintering treatments were characterized by XDR and scanning electron microscopy (SEM). The BMW presented a mineralogical composition suitable for use as ceramic raw material. In summary, our results presented that the new sustainable ceramic formulations sintered at 1250 °C have the potential for use in stoneware and porcelain stoneware.

With technological advances in the several areas of knowledge, the constant search for materials with characteristics that meet certain applications has been growing, especially in the chemical and petrochemical industries, where materials capable of withstanding the conditions of corrosion in aggressive environments are required. The aim of this paper was to analyze the influence of the alloy element molybdenum on the microstructure and the resistance to corrosion of two duplex stainless steels identified as A (with molybdenum) and B (without molybdenum), after solution-treated under the following conditions: heating at 1100ºC for 30, 120 and 240 minutes. The steels were characterized by SEM, EDS, DRX and microhardness. The rise in solution treatment time fostered an increase in the volumetric fraction of the ferrite phase, in both steels. The solution treatment at 1100ºC for 120 minutes, for steels A and B, provided good resistance to pit corrosion, as well as the development of a passivating film in the solution of lithium chloride (120,000 ppm of chloride ions).

The high-power impulse magnetron sputtering (HiPIMS) technique was applied to deposit multilayer-like (Cr, Y)N_x coatings on AISI 304L stainless steel, using pendular substrate oscillation and a Cr-Y target and varying the nitrogen flow rate from 10 to 50 sccm. The microstructure, mechanical and tribological properties were investigated by scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, instrumented nano-hardness, and wear tests. The columnar grain structure became highly segmented and nanosized due to pendular substrate oscillation and the addition of yttrium. The deposition rate increased continuously with the growing nitrogen flow rate. The increase in nitrogen flow from 10 to 50 sccm increased the hardness of the coatings (Cr, Y)N_x, with a maximum hardness value of 32.7 GPa for the coating (Cr, Y)N_x with a nitrogen flow of 50 sccm, which greatly surpasses the hardness of CrN films with multilayer-like (Cr, Y)N_x coatings architecture. The best mechanical and tribological performance was achieved for a nitrogen flow rate of 50 sccm. This was enabled by more elevated compressive stresses and impact energies of the impinging ions during film growth, owing to an increase of HiPIMS peak voltage with a rising N2/Ar ratio.