M. O. NWANKWO ET AL.

372

Table 9. Model summary and parameter estimates of the unified equation.

Dependent Variable: Y

Model Summary Parameter Estimates

Equation R Square F df1 df2 Sig. Constant b1 b2

Quadratic 0.935 171.551 2 24 0.000 1.032 −0.002 1.889E-6

The independent variable is T.

Regression Equation: 62

1.0320.0021.899 10

tt

.

5. Conclusion

The conclusion that can be drawn from the foregoing

discussions is that ocimum basilicum is a good corrosion

inhibitor since its pH value of 6.7 falls within the region

in which passivation occurs in the Poubaix diagram [20].

Again the quadratic model which fits each with a nearly

perfect correlation suggest in strong terms that room tem-

perature corrosion progression can no longer be said to

be only logarithmic but also has a significant quadratic part

that must be accounted for during corrosion characteriza-

tions. Additionally, the unification of the model equa-

tions into a single generalized form also shows that it is

henceforth possible and accurately so, to use the equation

to make futuristic computations of corrosion penetration

rates for engineering mild steel in acidic environments

with ocimum basilicum serving as a veritable inhibitor.

6. Acknowledgements

The authors wish to acknowledge the Department of In-

dustrial Chemistry of Ebonyi State University for grant-

ing them the permission to use their facilities for the

work. Dr. S. O. Maliki of the Department of Industrial

Mathematics, Ebonyi State University is also acknowl-

edged for his immense contributions.

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 Opportuni-

ties 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-corrosio

n-study.update/

[4] B. D. Craig, R. A. Lane and D. H. Rose, “Corrosion Pre-

vention 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 Maga-

zine 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 Met-

als, 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 Over-

book Press, New York, 1982.

[10] H. Ashassi-Sorkhabi, B. Shabani, B. Aligholipour and D.

Seifzadeh, “The Effect of Some Schiff Bases on the Cor-

rosion of Aluminum in Hydrochloric Acid Solution,” Ap-

plied 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 Inhibi-

tive 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, “Com-

parative 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 En-

gineering 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 Bas-

ed 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.

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