Colombia. A research conducted by a physics engineering student at the National University of Colombia, Manizales Headquarters, analyzed natural corrosion inhibitors such as coriander, avocado, mugwort, bitter sage and Bogota that create protective plates on steel that increase its useful life.
The inhibitors have an efficacy on steels of between 50% and 80% in cases of corrosion (electrochemical attack) and oxidation.
The student Daniel Pineda Hernández, explains that the degree of efficiency of natural products has been achieved from the study in the Plasma Physics laboratory of a new methodology that creates a coating on the steels.
"What we are looking for is that the industry has inhibitors that are not contaminants or toxic," says the researcher, who adds that, for example, the chemical deterioration of 304 stainless steel – which together with 316 are the most common grades – is avoided with the coating of bitter sage.
The contribution is essential to the extent that road and building construction megaprojects will increase demand for steel and this economic sector will increase. For example, the Colombian Committee of Steel Producers estimates that the demand for steel for concrete this year will be 6% and approximately 600,000 tons will be for housing projects subsidized by the Government.
Extraction process
For the method with bitter sage, the researcher took the leaves of the plant and macerated them until a fine powder was obtained. Then, through the Soxhlet extraction technique, he obtained the oil that acts as a plate or corrosion inhibitor. Once the product was obtained, he put it in a Teflon container along with the alloy -Acero 304-. Subsequently, in an Autoclave equipment - which increases the temperature by the action of a heating plate - the internal pressure of the steel increased.
Efficiency
To test the efficiency of the procedure, the coated steel was tested at the Gamry Potentiostat, using electrochemical impedance spectroscopy and potentiodynamic techniques. As a result, a resistance six times greater than that of steel without the inhibitor coating was obtained.
"The corrosion resistance of Steel 304 without an inhibitor is 134.4 ohms (Ω) – a unit of resistance to electric current. With the procedure, a resistance of 855.6 Ω was obtained, which shows that the method is efficient and raises the possibility of making these natural substances a product with commercial projection, "says Pineda Hernández. In this sense, the efficiency of the inhibitor was 84.29%.
Professor Belarmino Segura Giraldo, one of the supervisors of the project, highlights that in the laboratory of the U.N. Manizales Headquarters coatings and biological topics are studied, in the latter biocompatible materials are investigated and corrosion studies are carried out that apply to both industry and medicine.
Source: National University of Colombia.
Leave your comment