Papers by Keyword: Hydroxamic Acid

Abstract: Copper and its alloys are part of common used metals in the microelectronic industry. Copper uses, in microelectronic industry include interconnection and electronic packaging. The presence of copper in different alloys creates galvanic cells, which causes rising in corrosion rates. This rising leads to failure of microelectronic devices. The ability of controlling the amount of copper ions Cu (II) bath system has been carried out. The sorption of Cu (II) ions depends on pH, being maximum (73%) at pH=5 and pH=10. In solution of pH 5, the Cu (II) sorption capacity increases with the increase of copper initial concentration, leading to the conclusion that the chelating ion exchanger under study could be used in processes of Cu (II) separation and preconcentration. The Cu (II) ions equilibrium distribution between solution phase and sorbent phase has been described by means Langmuir isotherm model. The calculated value of Gibbs free energy (ΔG=-13.975 KJmol), confirms the affinity of the ion exchange resin with hydroxamic acid and amidoxime groups towards Cu (II) ions. The type of corrosion mechanism and its rate of attach depend on the exact nature of the environment (air, soil, water) in wich the corrosion takes place.

Abstract: Langmuir-Blodgett films (LB) of hydroxamic amphiphiles were used as coating barriers on metal surface against corrosion. Two long-chain hydroxamic acids [CH3(CH2)16CONHOH] monolayers in the presence of some divalent cations (Ca2+, Mg2+, and Cu2+) have been studied at different pH of the subphase. The monolayer was characterized by surface pressure-area isotherms and visualized by Brewster angle microscope (BAM). Compact Langmuir layers were deposited on copper surface, where the modified surfaces were characterized by contact angle measurement as well as by electrochemical techniques. The morphology of LB coated copper surface was visualized by atomic force microscopy (AFM). The coated copper surfaces were tested in corrosive media at acidic and neutral pH. The results show that the multi-molecular LB films of hydroxamic acid salts form good barriers against copper corrosion. The comparison of these results with copper coated by LB layers without divalent cations shows that the presence of divalent cations in the subphase increases the copper corrosion inhibition. The octadecanoyl hydroxamic acid (C18N) results in better and more stable monolayer with cations in the subphase.