CORROSION BEHAVIOURS OF HYDROXYAPATITE COATED BY BIOMIMETIC METHOD OF Ti6Al4V, Ti AND AISI 316L SS SUBSTRATES

Biomimetic method was used to obtain hydroxyapatite (HAP) coatings on Ti6Al4V, Ti and AISI 316L SS substrates. The solutions were prepared as 1.5xSBF and 3.0xSBF similarly to body fluid (SBF). Additionally, three different pretreatment surface operations (HNO3, anodic polarization, base-acid) were applied to the substrates. HAP coatings were successfully deposited on Ti6Al4V and Ti substrates after immersion periods of 14, 21, 35 days in 3.0xSBF. Corrosion behavior of uncoated and HAP coated substrates was examined in the Ringer and 0.9 % NaCl solutions. The SEM-EDS results pointed out that HAP was formed on the substrates. The best of HAP coated surfaces were obtained in 3.0xSBF and 1.5xSBF kept for 35 days. HAP coatings in 1.5xSBF were less thick than those in 3.0xSBF ones but have higher corrosion resistance.