An overview is reported about the history of prevailing magnesium alloys as orthopedic biodegradable materials. Important features of the effect of alloying additions, along with surface treatments for corrosion protection of magnesium alloys, are described. Hydroxyapatite (HA), the promising coat deposited by different direct and electrochemical methods to tailor corrosion resistance and biocompatibility, is discussed. Surface modifications, such as microarc oxidation or anodization which lead to nanostructures fabricated to provide better adhesion for HA coatings, are presented.

No abstract

No abstract

A new method was proposed for the application of azole corrosion inhibitors on the surface of copper. This method depends on the vacuum pyrolysis of the inhibitor in the presence of copper specimens. Three azole inhibitors namely; benzotriazole (Azole (1) (2)) and N-[Benzotriazol-1-yl-(4-methoxy-phenyl)-methylene]-N-phenyl-hydrazine (Azole (3)) were tested. After pyrolysis copper samples were electrochemically tested in sulfide polluted salt water and compared to the behavior of copper tested in the sulfide polluted salt water containing dissolved benzotriazole. Results showed that copper specimens treated in the presence of Azoles (2) and (3) exhibit excellent corrosion resistance. Those samples could resist the poisoning effect of sulfide ions. Azole (1) shows good resistance at low sulfide concentration and failed at the high concentration. Surface investigation support the results of electrochemical tests.

No abstract

No abstract

This paper treats the electrochemical oxidation of sulfide ions on platinum using cyclic voltametry.  An electrolyte of 3.5% NaCl containing sulfide ions was used as the testing medium.  The effects of scan rate, concentration of sulfide ions and temperature on the cyclic voltamograms were investigated.

Cyclic voltamograms show small currents in the absence of sulfide ions.  In the presence of sulfide ions, the magnitude of the anodic currents in the forward sweep is much more than these in the reverse sweep.  Cyclic voltamograms show three features appear in the forward sweep at potentials of  -0.1, 0.475 and 1.0 V vs Ag/AgCl, respectively.  Peaks currents are increased upon the increase of either the scan rate or temperature.  These peaks are explained to show the possible formed species and the possible electrochemical oxidation reactions at the electrode surface. 

No abstract