Surface reaction of magnesium in Hank's solutions

As magnesium is an essential element, magnesium implants can be expected to be safety though its corrosion resistance is low. To understand its corrosion behavior in vitro circumstance, for example Hank's solution and to improve its corrosion resistance, the present study was carried out. Specimens of 10×20×(2-4) mm³ were dipped in two kinds of Hank's solutions (without Ca and Mg ions-HBSS(-) and with Ca and Mg ions-HBSS(+)) for various periods (25-625 hours or to 1080 hours). Ratio of change of mass of each specimen was measured, the surface microstructure was observed by a scanning electron microscope, identification of corrosion product was examined by both techniques of an x-ray diffraction and a grazing incident x-ray diffraction. Chemical composition of reacted products was also analyzed by an energy dispersion x-ray technique. AZ91 alloy maintains a good corrosion resistance in both of HBSS(-) and HBSS(+) though AZ31 was completely melted within 4 days. Oxidized commercial pure Mg (3N-Mg) behaved stably good corrosion resistance in HBSS(+) though 3N-Mg did unstably corrosion resistance in HBSS(+). Magnesium reacted with HBSS(+) or (-) and then a certain substance was formed on the specimen surface. The substance consisted of Mg and P in HBSS(-), or of Mg, P, and Ca in HBSS(+). However, x-ray diffraction couldn't unfortunately identify many peaks, which showed the substance in content of Mg, P, or Ca. It can be succeeded to prepare crown and denture for dental use. The present study can conclude that magnesium is possible to apply to a biomaterial in the near future.