A comprehensive review on natural compounds as corrosion inhibitors for aluminium and aluminium alloys in different solutions is presented.

The aim of this review is to summarise the research work published in the last two decades on the use of organic compounds as corrosion inhibitors for aluminium and its alloys in acidic solutions. The focus is on HCl and H₂SO₄ solutions due to their extensive use in different applications, such as chemical and electrochemical etching, acid cleaning, anodising, and acid pickling of aluminium. Other acids are also reviewed. The inhibition effectiveness of numerous organic compounds and their possible inhibition type and mechanism are also discussed. Electrochemistry is mainly used to investigate inhibitor performance.

The properties of emulsions stabilized by nanosized cellulose particles (denominated also microfibrillated cellulose; MFC) were investigated. The wettability (hydrophobicity) of the MFC was changed through surface modification with chlorodimethyl isopropylsilane. The modified MFC was characterized with Fourier transform infrared spectroscopy (FTIR), and x-ray photoelectron spectroscopy (XPS). Using MFC of intermediate hydrophobicity resulted in water-in-oil emulsions within a range of oil/water ratios. The emulsifying capacity of the MFC was found to be proportional to both the relative amount of MFC used and its wettability (degree of surface substitution; DSS). The emulsions separated rapidly from the excess oil phase; the separated emulsion layers were highly stable towards gravity-induced sedimentation and, once a stable MFC network was formed, were also stable towards coalescence. The influence of the oil/water ratio, the concentration and DSS of the MFC on the stability of the emulsions toward coalescence, and the inversion to oil-in-water emulsions was also investigated. The results verify that MFC can be efficiently used as a stabilizer of oil/water emulsions within a range of oil/water ratios and particle concentrations.