2011 YÜksek lisans tez özetleri

Properties And Characterization Of Alumina-Bovine Hydroxyapatite (Bha) Composites Produced By Sol-Gel Method

In this study, production process and characterization analyses of sol-gel derived alumina covered bovine hydroxyapatite (BHA) particles are presented. Sol-gel process is a preferred method in bioceramic material production due to its usage advantages such as in the fabrication of products with high purity, in homogenous mixing at molecular level, at relatively low working temperatures, etc. Bioceramics, an important class of biomaterials, can fulfill the need for a number of implants and prostheses. “Bioinert” alumina and “bioactive” hydroxyapatite are the most frequently used bioceramic materials because of their suitable properties. Since tissue and cell growth/development is easier within their structure, porous materials become more important with respect to their porosity characteristics.

In the first part of this thesis study, boehmit sole (AlOOH) was obtained via sol-gel process by using aluminium isopropoxide (AIP, Al(OC₃H₇)₃) as the starting material. BHA (Ca₁₀(PO₄)₆(OH)₂) powders as % 10, % 20, % 30 and % 50 weight of the starting material were added to each boehmite sole. Natural BHA powders were derived from deproteinizated bovine bones. Also Na-alginate was added to the boehmite sole as the dispersive agent. Subsequently gelation for 3 hours at 110 ºC was applied to each sole mixture. Finally gelled samples were heat treated for 2 hours at 500 ºC, 800 ºC, 1000 ºC and 1300 ºC.

In the second part, characterization studies were performed on the alumina-BHA bioceramic powders that were obtained after heat treatment. DTA-TGA, FTIR, XRF, XRD, SEM-EDS characterization techniques were applied and corresponding outcomes are discussed in this thesis. Results generated by these characterization studies show that porous bioceramic composite structures can be produced through sol-gel process. Using the phase analysis outcomes it can be deduced that corundum (α-alumina), hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) phases exist together. If the scanning electron microscope (SEM) images of these biocompatible phases are carefully observed it can be seen that HA and β-TCP particles are surrounded with needle shaped alumina particles. Since porosity in bioceramic structures is a desirable property for tissue and cell growth/development, high porosity in alumina-BHA composites can be noted as a very interesting and useful result.

In the third and last part of this study, porous alumina-BHA bioceramic powders were pressed with hydrolic manual press in stainless steel folds and formed into pellets. Later these pellets were sintered for 2 hours at 1300 ºC. Physical and mechanic tests such as microhardness, open porosity, bulk density, cold compression strength were applied to the sintered pellets. The evaluation of these test results indicate that a novel alumina-BHA-TCP bioceramic composite material with ~ % 38-44 open porosity has been produced.

YILMAZ Uğur

Danışman : Prof. Dr. Enver OKTAY

Anabilim Dalı : Metalurji ve Malzeme Mühendisliği

Mezuniyet Yılı : 2011

Tez Savunma Jürisi : Prof. Dr. Enver OKTAY

Prof. Dr. İbrahim YUSUFOĞLU

Prof. Dr. Suat YILMAZ

Prof. Dr. Şerafettin EROĞLU,

Prof. Dr. Ercan AÇMA