Unification of the Quadratic Model Equations of the Inhibition Characteristics of Acidified Ocimum Basilicum on the Corrosion Behaviour of Mild Steel

Michael O. Nwankwo, Paul A. Nwobasi, Peter O. Offor, Ndubuisi E. Idenyi

Department of Industrial Physics, Ebonyi State University, Abakaliki, Nigeria.
Department of Metallurgical and Materials Engineering, University of Nigeria, Nsukka, Nigeria.
Department of Technology and Vocational Education, Ebonyi State University, Abakaliki, Nigeria.

DOI: 10.4236/jmmce.2013.16057                

Abstract

An attempt has been made at unifying the resulting quadratic models from the study of the correlation behavior of the inhibition characteristics of acidified ocimum basilicum on conventional mild steel. Weight-loss corrosion technique was employed in obtaining the corrosion penetration rate using the equation: cpr = . Subsequently, the quadratic models were developed by using a computer-aided statistical modeling technique (International Business Machine (IBM)’s SPSS version 17.0). The results obtained showed a nearly perfect positive correlation with a correlation coefficient in the range of 0.986 ≤ R ≤ 0.996 which depicts that R ≥ 1. Also, the coefficient of determination fell within the range of 0.972 ≤ R² ≤ 0.992 showing that approximately 97% to 99% of the total variation in passivation rate was accounted for by corresponding variation in exposure time, leaving out only between 3% and 1% to extraneous factors that are not incorporated into the model equations. The equations were further unified into a generalized form using MathCAD 7.0 and the resulting equation was y = 1.032 － 0.002t + 1.899 × 10^-6t² with a R² value of 0.935 indicating a well-correlated relationship. With this, a new frontier on corrosion studies has emerged typifying a classical departure from previously long-held assumption that corrosion behaviours at room temperature were only logarithmic.

Keywords

Corrosion; Inhibition; Ocimum Basilicum; Correlation; Quadratic Models; Passivation

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	M. G. Fontana, “Corrosion Engineering,” Tata McGraw-Hill Publishing Company Ltd., New Delhi, 2005.
[2]	D. J. Duquette and R. E. Schafrik, “Research Opportunities in Corrosion Science and Engineering,” National Academy of Sciences, Washington DC, 2011.
[3]	G2MTLabs, “Cost of Corrosion in 2013 in the United States Exceeds $1 Trillion,” 2011. http://www.g2mtlabs.com/2011/06/nace-cost-of-corrosion-study.update/
[4]	B. D. Craig, R. A. Lane and D. H. Rose, “Corrosion Prevention and Control: A Program Management Guide for Selecting Materials,” Alion Science and Technology, New York, 2006.
[5]	A. Boxer and P. Back, “The Herb Book,” Octopus Books Ltd., London, 1980.
[6]	J. A. Duke, “Culinary Herbs: A Potpourri,” Bouch Magazine Ltd., New York, 1985.
[7]	N. Kumpawat, A. Chaturvedi and R. K. Upadhyay, “Comparative Study of Corrosion Inhibition Efficiency of Naturally Occurring Ecofriendly Varieties of Holy Basil (Tulsi) for Tin in HNO3 Solution,” Open Journal of Metals, Vol. 2, No. 3, 2012, pp. 68-73. http://dx.doi.org/10.4236/ojmetal.2012.23010
[8]	W. C. Muenscher and M. A. Rice, “Garden Spice and Wild Pot-Herbs,” Cornell University Press, New York, 1978.
[9]	T. Stobart, “Herbs, Spices and Flavorings,” The Overbook Press, New York, 1982.
[10]	H. Ashassi-Sorkhabi, B. Shabani, B. Aligholipour and D. Seifzadeh, “The Effect of Some Schiff Bases on the Corrosion of Aluminum in Hydrochloric Acid Solution,” Applied Surface Sciences, Vol. 252, No. 12, 2006, pp. 4039-4047. http://dx.doi.org/10.1016/j.apsusc.2005.02.148
[11]	O. K. Abiola, N. C. Okafor, E. E. Ebenso and N. M. Nwinuka, “Ecofriendly Corrosion Inhibitors: The Inhibitive Actions of Delonix Regia Extract for Corrosion of Aluminum in Acidic Media,” Anticorrosion Methods and Materials, Vol. 54, No. 4, 2007, pp. 219-224. http://dx.doi.org/10.1108/00035590710762357
[12]	N. Kumpawat, A. Chaturvedi and R. K. Upadhyay, “Comparative Study of Corrosion Inhibition Efficiency of Stem and Leaves Extract of Ocimum Sanctum (Holy Basil) for Mild Steel in HCl Solution,” Protection of Metals and Physical Chemistry of Surfaces, Vol. 46, No. 2, 2010, pp. 267-270.
[13]	J. A. Soule, “Father Kino’s Herbs: Growing and Using Them,” Tierra del sol Institute Press, Tucson, 2011.
[14]	C. E. Ekuma and N. E. Idenyi, “Statistical Analysis of the Influence of Environment on Prediction of Corrosion from Its Parameters,” Research Journal of Physics, Vol. 1, No. 1, 2007, pp. 27-34. http://dx.doi.org/10.3923/rjp.2007.27.34
[15]	C. E. Ekuma, N. E. Idenyi and I. O. Owate, “Application of Statistical Technique to the Analysis of Passivation of Al-Zn Alloy Systems in Brine,” Journal of Chemical Engineering and Materials Science, Vol. 1 No. 1, 2010, pp. 1-7.
[16]	C. I. Nwoye, N. E. Idenyi and J. U. Odo, “Predictability of Corrosion Rates of Aluminum-Manganese Alloys Based on Initial Weights and Exposure Time in Atmosphere,” Nigerian Journal of Materials Science and Engineering, Vol. 3, No. 1, 2012, pp. 8-14.
[17]	M. O. Nwankwo, P. A. Nwobasi, S. I. Neife and N. E. Idenyi, “Statistical Studies of the Inhibition Characteristics of Acidified Ocimum Basilicum on Engineering Mild Steel,” Journal of Metallurgical Engineering, Vol. 2, No. 4, 2013, in press.
[18]	C. Nwoye, S. Neife, E. Ameh, A. Nwobasi and N. Idenyi, “Predictability of Al-Mn Alloy Exposure Time Based on Its As-Cast Weight and Corrosion Rate in Sea Water Environment,” Journal of Minerals and Materials Characterization and Engineering, 2013, in press.
[19]	W. D. Callister, “Materials Science and Engineering: An Introduction,” John Wiley and Sons Inc., New York, 1997.
[20]	M. C. N. Ijomah, “Elements of Corrosion and Protection Theory,” Auto-Century Publishing Company Ltd., Enugu, 1991.