تاثير مقدار و نوع نانو بيوسراميك تقويت كننده بر خواص مكانيكي كامپوزيت آلياژ پايه كبالت- بيو سراميك نانو متري

چكيده انگليسي :

115 The Effect of Amount and Type of Nanobioceramic on Mechanical Properties of Co based Alloy Composites Reinforced with Nanobioceramics Mojgan Bahrami m bahrami@ma iut ac ir April 20 2011 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiProf Mohammad Hossein Fathi Supervisor Email fathi@cc iut ac irAssist Prof Mahdi Ahmadian Supervisor Email ahmadian@cc iut ac irAbstractProgress in osseous surgery causes to improve biomaterials Among the modern materials used toorthopedic implants cobalt based alloys occupy an important place It is estimated that about 50 of artificial hip prosthesis are made of Co Cr Mo alloys vitallium Short life of current total hipreplacement implants is generally due to the aseptic loosening of the implant which occurs due to i mismatch of elastic modulus between bone and metallic implant materials leading to stress shielding ii poor interfacial bond between the host tissue and the implant due to bioinert surface iii wear induced osteolysis and aseptic loosening in metal on polymer implant In order toincrease the in vivo lifetime of metal implants one can decrease its effective modulus to match thatof bone and increase the interfacial bond between living cells and implant materials compositionalor structural modification Use of nano bioceramics such as fluorapatite hydroxyapatite andforsterite which are biocompatible and bioactive and composite fabrication could be successful In presented research the composite materials based on Co Cr Mo alloy with 10 15 and 20wt offluorapatite hydroxyapatite and forsterite nanopowder as reinforcement were fabricated The effectof type and amount of nano bioceramic reinforcement on the mechanical and bioactivity behaviorof composites were evaluated Composites were fabricated by mixing Co base alloy matrix andbioceramic reinforcement in planetary ball mill for 1hr cold pressing under 750 MPa and thensintering at 1100 C for 4hrs X ray diffraction XRD and scanning electron microscopy SEM were used for characterization and evaluation of the phase composition crystallite size ofreinforcements and particle distribution of composites Density microhardness compressivestrength elastic modulus and bioactivity of fabricated composites were evaluated To assessbioactivity bahavior of composites the immersion test was carried out in a simulated body fluid SBF for 1 28 days Obtained results showed elastic modulus of composite materials based onCo Cr Mo alloy reinforced with 10 15 and 20wt of fluorapatite hydroxyapatite and forsteritenanopowder decreased significantly With increasing in content of the reinforcement elasticmodulus of the composites was decreased which decreases the effect of stress shielding Resultsalso showed that the compressive strength of Co base alloy composites reinforced with 10 15 and20 wt fluorapatite hydroxyapatite and forsterite were lower than cast Co Cr Mo alloy Withincreasing in the content of reinforcement compressive strength of the composites were decreased Microhardness of prepared composites were higher than cast Co Cr Mo alloy With increasing incontent of bioceramic reinforcements microhardness of the composites were increased Ingenerally Co base alloy composites reinforced with 10wt reinforcement showed the maximumdensity microhardness compressive strength and elastic modulus Co base alloy compositesreinforced with forsterite nanopowder have higher mechanical properties Results of bioactivitytests showed that bioinert Co base alloy showed bioactivity behavior by adding bioactivenanoceramics in which apatite was formed on the surface The composites could haveossteointegration ability in comparison with cast Co base alloy The quantity of precipitated bone like apatite crystals on the surface of samples increased as bioceramic reinforcement bioactivephase in the composites content increased Keyword Co Cr Mo alloy fluorapatite nanopowder hydroxyapatite nanopowder forsteritenanopowde

بهرامي، مژگان

تاثير مقدار و نوع نانو بيوسراميك تقويت كننده بر خواص مكانيكي كامپوزيت آلياژ پايه كبالت- بيو سراميك نانو متري

فلوئور آپاتيت نانو متري , هيدروكسي آپاتيت نانو متري , فورستريت نانو متري , كامپوزيت زمينه آلياژ پايه كبالت , زيست فعال