13829

12571

كارشناسي ارشد

شناسايي و انتخاب مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

۱۳۹۷

يازده، ۱۰۰ص.: مصور، جدول، نمودار

مهشيد خرازيها، حميدرضا سليمي جزي

مهدي صالحي، شيدا لباف

1397/06/24

كتابنامه

مواد

مهندسي مواد

ID12571

101 Surface modification of Ti6Al4V alloy by using micro texture nanocomposite coating and evaluate its tribological and biological behavior in knee joint replacement application Mahboubeh Sadeghi m sadeghi1512@gmail com Date of submission 2018 06 13Degree M Sc Language FarsiSupervisors Mahshid Kharaziha Assist Prof E mail kharaziha@cc iut ac ir Hamidreza Salimi Jazi Assoc Prof E mail hrjazi@cc iut ac irAbstractRecent development in technology and increasing lifetime age related diseases such asmusculoskeletal disorders have been increasing Accordingly Ti6Al4V alloy could be efficientlyutilized for knee and hip joint replacement Main challenge in applying this alloy could be due toits weak tribological behavior and inert nature Therefore the aim of present research is to improvebiological and tribological properties of Ti6Al4V alloy through changing the surface topography ofimplant by laser and applying layered lubricant coating including graphene oxide polyvinylpyrrolidones PVP onto its surface Primarily micro dimples with different surfacedensities were deposited on the surface through laser the role of scanning rate of laser 0 5 10millimeter per second on mechanical chemical biological and tribological properties wasinvestigated and the optimized sample was selected In this research firstly the effect of solventtype various volume ratios of water ethanol water and Isopropyl alcohol the concentration ofgraphene oxide in the suspension 0 5 and 1 gr l as well as voltage 10 30 60 and 90 V and time 5 and 10 min of electrophoretic process on final coating properties were investigated In thesecond step PVP and tanic acid were coated on the substrate by means of electrophoretic process using a suspension containing various concentrations of polymer 0 3 0 5 and 1 gr l and tanic acid 0 2 0 3 0 5 and 1 gr l and different times 3 5 and 10 min Consequently the optimizedparameters of electrophoretic process were selected based on evaluation of coating morphology Finally the role of both micro dimple formation and two layer coating on the tribological andbiological properties was investigated Our results confirmed that the sample subjected to scanningrate of 5 mm s with diameter and surface density of micro dimples of 190 5 5 m and 21 2 0 56 respectively was the optimized sample in the terms of hardness biological and tribologicalproperties These results showed that the wear mechanism was changed from abrasive and plasticdeformation and delamination to abrasive mechanism at the optimized sample Moreover morestable Coefficient of friction was achieved for laser optimized sample After evaluating grapheneoxide coatings it could be concluded that suspension with 0 5 g l isopropanol and at optimizedelectrophoretic parameters 90 V and 10 min could provide more uniform coating rather than othercoating parameters In following two layer nanocomposite coating was prepared by using two stage electrophoretic process graphene oxide and then PVP The results obtained from 5 days ofcell culture of MG63 cells showed that two layer nanocomposite coating had higher cell viability 185 27 control than that of the on other samples Furthermore friction test results illustratedthat an increase in applying load reduced coefficient of friction in optimal surface modified sample Additionally coefficient of friction of optimal sample was significantly reduced about 11 times compared to control Generally it could be concluded that applying both micro dimple formationand lubricant coating simultaneously accompanied by tribological and biological improvementswhich might be useful in applications of knee joints implants Keywords Knee joint implant Ti6Al4V alloy Tribology Surface modification Electrophoretic

مهشيد خرازيها، حميدرضا سليمي جزي

مهدي صالحي، شيدا لباف