Institute of Fundamental Technological Research
Polish Academy of Sciences

Partners

Nnaji Nnaemeka


Recent publications
1.  Nnaemeka N., Nwaji N., John M., Tebello N., Ball-type phthalocyanines and reduced graphene oxide nanoparticles as separate and combined corrosion inhibitors of aluminium in HCl, Journal of molecular structure, ISSN: 0022-2860, DOI: 10.1016/j.molstruc.2021.130279, Vol.1236, pp.1-12, 2021

Abstract:
Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were
investigated for reduced graphene oxide nanosheets (rGONS), tetrakis-[4,4
-((4-(benzo[d]thiazol-2-yl)-
1,2-bis(phenoxy)] (diphthalocyaninato gallium (III) chloride) (2) and tetrakis-4-(hexadecane-1,2-dioxyl)-
bis(phthalocyaninato gallium(III) chloride) (1). Corrosion inhibition effects of rGONS, 1 and 2 were evaluated alone and in combination in 1.0 M hydrochloric acid solution using electrochemical techniques. The
mechanism of aluminum corrosion inhibition revealed predominantly anodic character for rGONS and
predominantly cathodic character for 1, 2, and conjugates with rGONS . The polarization technique gave
inhibition efficiency values of 96.5% and 96.9% respectively for 1 and 2, which increased in the presence
of rGONS to 97.4% and 98.1%, respectively, for the highest concentrations of 1 and 2. Scanning electron
microscopy revealed effective metal surface protection by the inhibitors by formation of protective films

Affiliations:
Nnaemeka N. - other affiliation
Nwaji N. - IPPT PAN
John M. - other affiliation
Tebello N. - other affiliation
2.  Nnaemeka N., Nwaji N., Gertrude F., John M., Tebello N., Inhibition of Aluminium Corrosion Using Benzothiazole and Its Phthalocyanine Derivative, Electrocatlysis, ISSN: 1868-5994, DOI: 10.1007/s12678-019-00538-1, Vol.10, pp.445-458, 2019

Abstract:
Cyclic voltammetry and potentiodynamic polarization techniques were used to study the effects of 4-[4-(1,3-benzothiazol-
2yl)phenoxy] phthalonitrile (BT) and tetrakis[(benzo[d]thiazol-2ylphenoxy) phthalocyaninato] gallium(III)chloride
(ClGaBTPc) as aluminium corrosion inhibitors in 1.0 M hydrochloric acid. The presence of the inhibitors in the concentration
range of 2 to 10 μM was found to retard the aluminium corrosion process such that the inhibition efficiency was found to range
from 28.2 to 76.1%for BTand from 71.5 to 82.7%for ClGaBTPc. The latter was a better inhibitor. Scanning electronmicroscopy
and energy-dispersive X-ray measurements reveal effective metal surface protection by the inhibitors, most probably by shielding
it from the corrosion attacks of Cl− from the acid. The calculated quantum chemical parameters agreed with experimental results

Affiliations:
Nnaemeka N. - other affiliation
Nwaji N. - IPPT PAN
Gertrude F. - other affiliation
John M. - other affiliation
Tebello N. - other affiliation
3.  Nnaemeka N., Nwaji N., John M., Tebello N., Corrosion Resistance of Aluminum against Acid Activation: Impact of Benzothiazole-Substituted Gallium Phthalocyanine, Molecules, ISSN: 1420-3049, DOI: 10.3390/molecules24010207, Vol.24, pp.4-22, 2019

Abstract:
This study describes the adsorption behavior of organic inhibitors at the aluminum-HCl
solution interface and their corrosion inhibition performance. The organic inhibitors employed are:
4-(benzo [d]thiazol-2ylthio)phthalonitrile (BTThio) and tetrakis[(benzo[d]thiazol-2-yl-thio)phthalocyaninato]
gallium(III) chloride (ClGaBTThioPc). The corrosion behavior of these inhibitors is
investigated using electrochemical and computational techniques. Open circuit potential results
reveal predominant cathodic character for the mechanism of aluminum corrosion inhibition by the
inhibitors. Inhibition efficiency values from potentiodynamic polarization measurements increase
from 46.9 to 70.8% for BTThio and 59.7 to 81.0% for ClGaBTThioPc within the concentration range of
2 to 10 M. Scanning electron microscopy (SEM) measurements reveal protection of the metal surface
from acid attack, in the presence of the inhibitors and energy dispersive X-ray (EDX) measurements
show that the most probable way by which the inhibitors protect the metal surface would be
by shielding it from the corrosion attacks of Cl

Affiliations:
Nnaemeka N. - other affiliation
Nwaji N. - IPPT PAN
John M. - other affiliation
Tebello N. - other affiliation

Category A Plus

IPPT PAN

logo ippt            Pawińskiego 5B, 02-106 Warsaw
  +48 22 826 12 81 (central)
  +48 22 826 98 15
 

Find Us

mapka
© Institute of Fundamental Technological Research Polish Academy of Sciences 2024