Microstructural corrosion effects on carbon foam-AZ31 magnesium matrix composite surface
Marcin Godzierz, Anita Olszówka-Myalska
Quarterly No. 3, 2018 pages 133-139
DOI:
keywords: magnesium matrix composite, carbon open-celled foam, corrosion, interface, biomaterials
abstract In the article, a new composite was studied as a potential biomaterial. The effects of the interaction of distilled water with the polished surface of an AZ31 magnesium matrix composite reinforced with open-celled glassy carbon foam fabricated by the pressure infiltration method were investigated. The experiment was conducted in the time range of 1 minute - 4 hours and the microstructure was examined by scanning electron microscopy. In the initial unetched material, at the glassy carbonmetal interface, a zone of needle-like phases was detected. After a 1÷10 minute interaction with the water, disintegration of that zone was revealed and that type of material degradation proceeded deeper into the composite as the time increased. Another type of corrosion was observed in microareas of the magnesium alloy matrix, but only after approx. 1 hour when corrosion pits were recorded. The results of X-ray mapping showed an increase in the oxygen concentration in both types of corrosion products, but the reason for the corrosion in the region between the carbon foam and the AZ31 matrix is degradation of the hydrophilic aluminium based carbide phases, while in the composite matrix, typical electrochemical corrosion of magnesium occurred.