No abstract

Hydroxyapatite (HAP) has been coated onto Ti6Al4V and 316L SS substrates by sol-gel method. The coating thicknesses for the analysis were about 40 and 72 lm. Adhesion and corrosion tests have been conducted on uncoated and HAP-coated substrates. The coatings were characterized by XRD, SEM, and adhesion analysis. The corrosion resistance was examined in vitro by potentiodynamic polarization technique in RingerÕs solution at room temperature. Electrochemical analysis indicated that the highest corrosion susceptibility was found on 72-lm-coated 316L SS, and the 40-lm HAP-coated Ti6Al4V showed the highest corrosion resistance. It was observed that the coating thickness was an effective parameter on both adhesion and corrosion resistance. It was shown that adhesion and corrosion resistance decreased with increasing coating thickness on both substrates.

No abstract

The influence of age hardening on the corrosion behavior of Al-Si-Mg-based metal matrix composites (MMCs) has been investigated in aerated and deaerated 3.5 wt% aqueous NaCl solutions. Silicon carbide particle (SiC p ) reinforced composites consisting of 10 and 20 vol% SiC p s are produced by the compocasting technique. After the extrusion process, the composites are artificially aged (T6). The corrosion resistances of the aged composites are analyzed by measuring the cyclic potentiodynamic polarization. The surface morphology of the composites before and after the corrosion tests are determined by using metallographic methods and scanning electron microscopy (SEM). In addition, the X-ray diffraction technique (XRD) has been used to determine the phases that occur at the matrix-reinforcement interface. The results demonstrate that the E pit values of unreinforced matrix alloy and composites increase negatively with increasing aging time. It is also observed that corrosion preferentially starts at the interface of Al-Mg 2 Si and Al-SiC p .

No abstract