Problems With Solar Power System
Steel and iron are the top materials that are being used by the engineers for construction purposes. Since many years, the greatest concern for engineers and corrosion researchers have been to analyze the corrosion causing phenomenon that deteriorates the material especially carbon steel and iron resulting in huge financial loss and disasters every year. Atmospheric corrosion is the deterioration of the material as it starts to react with the environment resulting in serious threats towards personal safety. It is important to figure out the process of atmospheric corrosion so that the corrosion can be controlled as around 80% of the degradation in steel and iron is caused by atmospheric corrosion. Literature has been plagued with ways to find out about the contributory environmental factors that cause carbon steel corrosion and the optimum solution for protecting steel from deterioration. The research has been done using the University database and other journal databases like JSTOR and Springer. This literature review will focus on main causes of carbon steel corrosion which are humidity, temperature and pollutants alongside with their solutions.
Humidity
According to Badea et al. (2011), the foremost cause of carbon steel corrosion is caused by humidity as a thin electrolyte film appears on the metallic surfaces of the steel after certain critical level of humidity has been reached. One of the key factors of corrosion is presence of electrolytes on the corroding surface which is mostly caused due to humidity. Badea et al. (2011) stated that at least 70% of the carbon steel corrodes due to high level of relative humidity. Cao et al. (2015) also conducted various experiments to test the effect of humidity on the corrosion of carbon steel and iron and concluded that as the relative humidity in chambers decreases, the water layers on carbon steel evaporate and become thin or disappear in most cases resulting in decreased corrosion activity. Cao et al. (2013) showed that humidity has the highest grey relational grade when it comes to corrosion as it was determined that in one year atmospheric exposure, relative humidity has the highest impact on the corrosion rate. The wetting of the surface is increased due to increase in humidity and cause Q235 steel to corrode at faster rate as per the results of Cao et al. (2013) experiments. Ye et al. (2015) analyzed the possible candidates for anti-corrosion coating and recommended Graphene due to its unique properties like impermeability, conductivity and inertness. By growing graphene on carbon steel through the Ni elements and Fe alloys, the corrosion can be resisted up to 7 times against corrosions according to Ye et al. (2015).
Temperature
The second main factor of corrosion has been found out to be temperature by Badea et al. (2011). Temperature has a complex effect on the atmospheric corrosion rate of carbon steel as it was analyzed by Badea et al. (2011) that an increase in temperature stimulates the attack by corrosive substances and leads to higher corrosion rate of carbon steel. The relationship between temperature and humidity was also seen to be complex as by increasing temperature, the relative humidity decreases which causes the thin electrolyte layer to evaporate and result in slow corrosion activity as according to Badea et al. (2011). It was also predicted by Badea et al. (2011) that as temperature decreases, the atmospheric corrosion rate increases at faster pace. The solution provided by Ye et al. (2015) was that Graphene can be grown on copper steel can perform really well in resisting the harsh temperature of the environment and other factors. It performs as an anti-corrosion layer and protect steel from corrosion as according to Ye et al. (2015). Similarly the experiments conducted by Park et al. (2014) also indicated the suitability of using Graphene as an anti-corrosive shield. Park et al. (2014) used electrophoretic disposition to grow graphene oxide on carbon steel by using a GO water suspension which formed a barrier layer on the carbon steel to protect it from corroding. The GO and EPD performed together to reduce the corrosion and improve anti-corrosion performance of the steel by acting as a barrier against corrosion of steel. Hence, Graphene can be used to reduce corrosion caused by temperature based on the field studies done by Ye et al. (2015) and Park et al. (2014).
Pollutants
The third main factor of carbon steel corrosion has been found out to be Atmospheric contaminants particularly pollutants like Sulphur dioxide as per according to Badea et al. (2011). The presence of gaseous air pollutants and other environmental factors like Sulphur dioxide and nitrogen accelerate the corrosion activity of carbon steel with the formation of green rust on the surface of carbon steel. Cao et al. (2015) also concluded that sulfide pollutants and chlorides are considered to be the most important factors when it comes to atmospheric corrosion. Another experiment conducted by Cao at al. (2013) showed that sulphur dioxide and precipitated salts were the two most important air pollutants that contributed towards the corrosion of metals as indicated by atmospheric corrosion monitor. A quite different solution is proposed by Emira et al. (2015) as the experiments contained the testing of anti-corrosion performance of inorganic pigments that are found in paints. The experiment conducted by Emira et al. (2015) pointed towards usefulness of five paints to act as an anti-corrosive barriers. Zinc phosphate was found out to be the best material to protect the steel from corroding along with chlorinated rubber as it protected the steel due to its good barrier properties for water and oxygen.
Conclusion
In conclusion, the majority of research and experiments conducted have been examined properly and reflected the core environmental factors that accelerated the corrosion activity in steel and iron. Especially the work of Badea et al. (2011) and Cao et al. (2015) considered the relationship between humidity levels and corrosion activity while the solutions to slow down the corrosion activity was given by Ye et al. (2015) and Park et al. (2014). The effect of pollutants especially Sulphur dioxide and salt particles were also examined by Cao et al. (2013) and holds great potential for further exploration. Bade et al. (2011) also proposed the importance of type of environment (rural, urban, industrial or a mixture) for determining the severity of the atmospheric corrosion in the carbon steel and iron. The study by Emira et al. (2015) also is of great importance as it promotes the usage of paints and pigments to reduce the corrosion in carbon steel. However, due to experimental approach that is used by most of the researchers, the results may differ for any given environment. The corrosion rate depends on several other factors in which the time and degree of protection applied are of great consideration. The time of wetness, different voltages, season and geographic zone are some other important factors that are usually ignored when studying the process of corrosion of carbon steel and iron. However, due to their unavailability for testing in the labs, these variables regardless of their importance are not studied much.
References:
- Badea, G. E, Cret, P, Lolea, M, & Setel, A 2011, ‘Studies of carbon steel corrosion in atmospheric conditions’, Acta technical corviniensis-bulletin of engineering, 4 (4), p. 25-28.
- Cao, X, Deng, H, Lan, W, & Cao, P 2013,‘Electrochemical investigation on atmospheric corrosion of carbon steel under different environmental parameters’, Anti-Corrosion Methods and Materials, 60(4), p. 199-205.
- Cao, X, Deng, H, & Lan, W 2015, ‘Use of the grey relational analysis method to determine the important environmental factors that affect the atmospheric corrosion of Q235 carbon steel’, Anti-Corrosion Methods and Materials, 62(1), p. 7-12.
- Emira, H S, Shakour, A A, Abd El Rehim, S S, Saleh, I A, & El-Hashemy, M A 2012, “Evaluation of corrosion protection of carbon steel by anticorrosive paints”, Anti-Corrosion Methods and Materials, 59 (5), p. 255-262.
- Park, J. H, & Park, J. M 2014,’ Electrophoretic deposition of graphene oxide on mild carbon steel for anti-corrosion application’, Surface and Coatings Technology, 254(1), p. 167-174.
- Ye, X, Lin, Z, Zhang, H, Zhu, H, Liu, Z, & Zhong, M 2015, ‘Protecting carbon steel from corrosion by laser in situ grown graphene films’, Carbon, 94(1), p. 326-334.
