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This paper aims to investigate the stability of passive oxide film formed on the surface of 316L stainless steel in 3.5 Wt.% NaCl in the presence of two environmentally non-toxic inhibitors, i.e. leaf extracts of Musa spp. (MS) and Jatropha curcas (JC).

Current transients and potentiodynamic polarization curves were used to explain the stability of the passive film on Current transients and potentiodynamic polarization curves were used to explain the stability of the passive film on 316L stainless steel at both ambient temperature (25 °C) and 70 °C. For the potentiostatic tests, the coupons underwent cathodic stripping to remove the native oxide on their surfaces at −850 mV for 600 s, and a potential of 50 mV was imposed to observe the repassivation for 200 s. For the potentiodynamic tests, the pitting potential measured at 100 μA/cm2, corrosion potential and cathodic current density were obtained for analysis.

The current transients perfectly fitted into the exponential decay curve; i = i_s + i_peak exp(−t/τ), where the decay constant, τ measures the repassivating speed and extent to which the newly formed film heals and stabilizes. The current transients showed that MS and JC help in the repassivating process, especially at 300 ppm and 200 ppm, respectively, both at the lower temperature. The potentiodynamic curves mostly correlated with the current transients except for the hybrid inhibitor. The inhibitors increased the pitting potentials at concentrations that are correlated to their scanning electron micrograph images.

Because they are cheap and environmentally friendly, plant extracts that are proven corrosion inhibitors could be used to aid the formation of passive film on passive alloys in not-so-aggressive environments.

Both MS and JC improve the film stability mostly at intermediate concentrations of 200 and 300 ppm, respectively, at ambient temperature and 70° C.

Using leaf extracts of plants as green inhibitors is considered an environmentally friendly engineering solution.

The leaf extracts are a convenient resource of green inhibitors because their plants are readily available or could be easily naturalized, the processing technique to obtain the extracts is very cheap and the inhibitors are environmentally friendly. In addition, cathodic stripping exposes a relatively larger surface area than that obtained using the most common forms of depassivation; hence, the efficiency of the inhibitor in aiding the formation of the new oxide film to cover the bare surface would be better measured. There is very lean research data on the combined use of green inhibitors and cathodic stripping to study repassivating kinetics of passive alloys.

The purpose of this study is to examine gender and rural economic relations of the Nrobo of Southeastern Nigeria. Specifically, the study was designed to examine the subsistence strategies, gendered role patterns and gender gaps in economic relations of the Nrobo.

This study used ethnographic methods of participant observation – adopting chitchatting and semi-structured interviews. Also, focus group discussion (FGD) was used to cross-check the validity of data from the other instrument.

This study found among other things, that although there is still verbal expression of gendered roles division, it does not mirror what actually obtains in society, except bio-social roles. Ideological superiority of men reflects the patrilineal kinship arrangement of society. Theoretically, some of the hypotheses of gender inequality theory were disputed for lack of adequate explanation of gender and economic relations in an egalitarian-reflected society such as Nrobo.

This study, to the best of my knowledge, is the first attempt to ethnographically examine gender and economic relations among this group. As such it adds to the corpus of ethnographies on the Igbo of Southeastern Nigeria.