engleski

The impact of essential oils (laurel, basil and dill) on corrosion behaviour of Al-Mg alloy in model solutions

The essential oils have been in use for many years in industries, especially in the pharmaceutical, cosmetic and sanitary industry. Recently, many essential oils are used in culinary and food industry as spices and flavouring agents. Aluminium alloys with magnesium are one of the most important construction materials, especially in shipbuilding, but also for use in the chemical and food industry. Despite the good properties of Al-Mg alloys, they are not perfect materials for engineering applications in all environments, since they suffer from corrosion caused by chemical interactions with their surroundings. For the selection of aluminium and its alloys for the needs of the food industry, their good corrosion resistance to most food products is particularly important. High corrosively environment for aluminium and aluminium alloys in food industry are foodstuffs with pH 3 – 5, such as fruit juices, canned fruits, sauces as well as vegetables and fish pickled in brines with 1 –3 % salt. For this reason, NaCl and acetic acid needs to be taken into corrosion consideration, due to its wide usage in food industry. This study was carried out on AA5754 alloy (aluminium alloy with 3% of magnesium) using gravimetric and potentiodynamic polarization methods, while the alloy surfaces were examined by scanning electron microscopy (SEM). Corrosion study of AA5754 alloy in 3 % NaCl, 1 % CH3COOH and their mixture with addition of 20 ppm laurel, basil and dill essential oils as three very commonly used herbs to improve food flavorings, was conducted in temperature range 25°C to 80°C. Results show that the best inhibitory action on Al-Mg alloy corrosion have basil oil at all investigated temperatures, especially in mixture of 3% NaCl and 1% CH3COOH solutions.

Al-Mg alloy, corrosion, essential oil, inhibition, model solution

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