3966

3744

كارشناسي ارشد

شناسايي و انتخاب مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده موتد

1386

نه، 80، [II]ص.: مصور، جدول، نمودار

ص.ع. به: فارسي و انگليسي

محمد حسين فتحي

احمد منشي

26/03/87

رحمت اله عمادي، اميرعباس نوربخش

مهندسي مواد

ID3744

به فارسي و انگليسي: قابل رؤيت در نسخه ديجيتال

AbstractYttria stabilized tetragonal zirconia polycrystals YTZP were introduced to the biomaterialsworld due to its advantageous properties such as superior strength toughness and wearresistance The main application of this ceramic biomaterial is in the manufacture of ballheads for total hip replacements THR and dental restorations In this study 3Y TZPpowders were prepared by a simple sol gel rout and its characteristics were evaluated Appropriate amount of zirconium oxide chloride ZrOC12 8H2O and yttrium nitrate Y NO3 3 6H2O to reach 3mol yttrium oxide in final product were mixed in anhydrousethanol on a magnetic stirrer After drying the obtained gel it was calcined at differenttime and temperatures The thermal behavior of the dried gel was investigated bystimulated thermal analysis STA Phase identification particle size and its distributionand microstructural investigation were performed respectively using X ray diffractiontechnique XRD electron microscope SEM TEM and zeta sizer Nitrogen gasadsorption was also utilized to evaluate the BET specific surface area of the synthesizedpowder The result of thermal analysis of dried gel showed no thermal effect after 600 C sothe optimum calcinations temperature was determined as 600 C The XRD pattern ofdried gel showed that the sample was quasi amorphous while the XRD pattern of calcinedpowders revealed that the diffraction peaks are characteristics of tetragonal zirconia phasewhich shows that TZP has been obtained Crystallite size of the powder evaluated by theScherer equation and x ray diffraction data is about of 20 nm SEM and TEM studiesrespectively confirm the presence of agglomerates in powders with average size about 80nm and crystallites of about 20 nm Increasing the calcination temperature up to 1200 Cdid not cause formation of any new phase in the structure of powder Crystallite growthdue to the increase in calcination temperature was only up to 36 nm These facts show thatthe synthesized powders have a very good thermal stability and remain nano crystal evenat high temperature near sintering one Furthermore results confirmed that the sol gelprocess utilized in this study is capable of development of homogenous distribution ofyttria in the synthesized powder and stabilization of tetragonal phase at higher temperatureof calcinations

محمد حسين فتحي

احمد منشي

رحمت اله عمادي، اميرعباس نوربخش