Aluminum alloys are extensively used to manufacture mechanical components. However, when exposed to alkaline environments, like lubricants, refrigerants, or detergents, they can be corroded, reducing their durability. For this reason, the aim of this study is to investigate the influence of aggressive alkaline solutions (i.e., pH and presence of chlorides) on the corrosion resistance of three aluminum alloys (AA 5083-H111, AA 6082-T6, and AA 7075-T6) with and without anodizing treatments. Open circuit potential (E_OCP) and anodic polarization measurements were carried out and typical corrosion parameters such as corrosion current density (i_cor) and corrosion rate (CR) were determined. Morphology of the corrosion attack and samples microstructure were investigated by scanning electron microscope. Results show that corrosion behavior of the three investigated alloys is influenced by (i) the aggressiveness of the testing environments; (ii) the thickness of the anodizing treatment; (iii) the alloy chemical composition; (iv) the distribution of intermetallic phases in the aluminum matrix. Moreover, three galvanic series have been built also testing other metallic alloys commonly used in mechanical applications, i.e., carbon steel (C40), stainless-steel (AISI 304), and Cu-based alloys (Cu-Ni alloy and CW 617 N, respectively). Results clearly indicate that galvanic series play a fundamental role when it is necessary to select an alloy for a specific environment, highlighting the thermodynamic conditions for corrosion occurrence. On the other hand, kinetic measurements and microstructural studies carried out on the three aluminum alloys stress the importance of the surface treatments and relevant thickness as well as the effect of metal exposure. Future work will involve the study of other surface treatments on aluminum alloys and the evaluation of their corrosion behavior in acidic environments.

The aim of the work is to design and validate a characterization protocol for glazes used in the ceramic tile industry to lead manufacturers and researchers towards the formulation of glazes with enhanced wear resistance properties. The focus of the protocol is addressed to determine surface parameters that strongly depend on glaze formulation and firing temperature. This protocol includes analytical (e.g., thermal analysis, Vickers microhardness, microstructural investigation, etc.) and technological tests (i.e., impact resistance and surface abrasion resistance test), the latter carried out on ceramic tile samples where four different glazes have been applied. The characterization protocol set in this paper highlights the importance of using both analytical and technological tests for glaze investigations and provides threshold values for specific parameters useful in developing glass-ceramic glazes with enhanced mechanical and tribological properties.