BIOACTIVE SURFACE MODIFICATION BY PLASMA SPRAY COATING PROCESS

摘要

Ti-6Al-4V ELI alloy is normally used for orthopedic and dental prostheses. When the alloy is implanted in the human body, Al is suspected to cause nervous and mental disease. Also, V is suspected to cause serious damage on the surrounding organs and cells. Therefore, titanium alloy of good biocompatibility, mechanical and chemical stability without Al and V has been demanded. In this study, for the purpose of blocking of eluted harmful elements in the human body Ti-6Al-4V ELI alloy was coated with pure Ti by using plasma-spray-coating process. And to improve the bone-bonding ability between Ti-based alloy and living bone, surface modification was performed on the implant by the chemically and thermally activated processes. The surface modification of the implant by alkali and heat treatment (AHT), alkali treated in 10.0M NaOH solution and heat treated in vacuum furnace at 600℃, is reported. After AHT, the effects of the AHT on the bone integration property were evaluated in vitro and bone-bonding strength was studied by pull-out test after in vivo study. Surface morphologies of the implant after AHT were observed by optical microscopy (OM) and scanning electron microscopy (SEM). Chemical compositional surface changes were investigated by energy dispersive spectroscopy (EDS) and electron probe micro analyzer (EPMA). The pull-out strength between living bone and implant was performed by universal testing machine (UTM).