Corrosion behaviour of electrochemically joined aluminum and stainless steel

Two dissimilar metals viz., aluminum and stainless steel (SS) were joined electrochemically by heavy nickel deposition. Potential-time behavior, Tafel extrapolation method and galvanic coupling experiments were conducted to study the corrosion behavior of the three individual metals in 5% aqueous sodium chloride acidified with acetic acid, alone and in combination. The systems behaved differently in simple immersion test and on coupling with each other. In simple immersion test, nickel and SS were nobler to aluminum. Coupling of aluminum and nickel (bi-metallic) resulted in dissolution of both metals, the rate of nickel being lower. Potentiodynamic polarization experiments showed that the aluminum-SS bi-metallic system has the highest corrosion rate than aluminum-Ni or SS-nickel. Aluminum exhibits pitting type corrosion when coupled to nickel. Experiments with electroplated specimens and SEM analysis confirmed that in aluminum-nickel couple both metals corrode, the corrosion of nickel being considerably lower. Formation of elemental nickel on aluminum surface also confirmed the above result

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Not Availablea greater amount of additive genetic variance between lines and permit backcrossing for the transfer of desirable traits. Large number of inbred lines of popular cassava varieties and elite clones developed at Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala were screened for desirable traits and used in heterosis breeding programme. Promising backcross hybrids were developed from elite inbred lines as well as two advanced backcross lines of an interspecific hybrid of cassava with Manihot tristis having higher crude protein (8-10%) on dry weight basis in their roots. The clones exhibited high variation for crude protein in tubers with a range of 1.11% - 10.40% and 0.37% to 2.74% on dry and fresh weight basis respectively. Of the sixteen high protein clones, four clones viz. CPH-75, CPH-105, CPT-88, CPT-109 had crude protein at levels of >2.0% (fresh weight basis). Crude protein content of cassava had high significant negative correlations of -0.4812 and -0.4741 with dry matter and starch contents respectively. Present study revealed high variation for root dry matter (7.57%-49.60% ) and starch content (4.01%-42.00% ) among inbred lines (S2 ) of elite cassava clones. Highly significant positive correlation of 0.8187 was observed between dry matter (DM) percentage and starch in the clonal populations.Not Availabl