Corrosion mitigation of stainless steel in milk by aloevera juice

Abstract

Not only does the corrosion of metals by milk become an economic problem from the point of view of equipment replacement, but it is important also from the marketability and physiological factors involved. Milk is very an essential food for human beings. It is highly rich protein containing substance. Generally People keep milk in stainless steel can. Stainless steel uses pasteurizing, storage and transportation of milk. Milk develop corrosion cell on the surface of metal thus stainless steel starts corroding. Improper equipment may lead to contamination of the milk by the products of corrosion to such an extent that not only is the flavor affected, but also the food value. The flavor may be affected by simple metal contamination, giving the characteristic metallic taste or by the indirect action of the dissolved metals on the microorganisms in the milk, resulting in the "mealy" flavor. Due to electrochemical reaction harmful metal goes into milk hence it is contaminated. The contaminated milk produces several types of diseases. To check such types of corrosion aloevera uses as inhibitors. It produces anticorrosive affect with milk. Its inhibition affects study at different concentrations and temperatures on different interval of times. Aloevera takes as concentrations of 2ml, 4ml and 6ml and temperatures maintain those concentrations 20OC, 25OC, 30OC and 35OC.The corrosion rate of stainless steel determined absence and presence of inhibitor at different concentrations and temperatures with help of gravimetric methods. The corrosion current with and without inhibitors calculated by potentiostatic polarization technique. The use inhibitor decreases the concentration of H+ and produce thin film on metal surface. The surface film adsorption phenomena study with help of Langmuir, Temkin and Arrhenius equation and other parameters are activation energy, free energy, heat adsorption, enthalpy and entropy. The thermodynamical results show that aloevera is bonded with metal by physical adsorption. The inhibition efficiency and surface coverage area increase as concentrations and temperatures of inhibitor increases.