EFFECT OF HEAT TREATMENT ON THE SURFACE MORPHOLOGY ON NaOH AND KOH TREATED Ti6Al4V

Abstract

Coating of apatite in biomimetic fluid is an alternative technique in metallic coating. An effective biomimetic apatite coating is depends on the surface material that can be enhancing through a chemical and thermally activated process. In this study, two kinds of alkali with same concentration of 5M NaOH and 5M KOH were used in the surface modification of Ti6Al4V at 60°C for 24h. In general, a passive oxide layer covered on Ti6Al4V surface changed to form alkali (Na/K) titanate layer which is mechanically unstable. Therefore, alkali-treated Ti6Al4V were heat treated at 500-800°C for 1h to consolidate a mechanically stable structure of amorphous alkali titanate layer. Surface morphologies and composition of Ti6Al4V before and after heat treatment were characterized using field emission scanning electron microscope (FESEM), equipped with energy dispersive X-Ray (EDX) probe. While, X-ray diffractometry (XRD) was used to examine surface chemical changes. Different alkali used at initial etching process showed a different morphologies structure which to be thought could enhanced bioactive characteristic. Thermal treatment on alkali treated Ti6Al4V alloy has limitation as heating above 700°C change porous structure to form a dense and solid non-porous networking structure.