Silicon nitride is one of the materials that has high potential to be utilized in biomaterials field due to its superior properties like high strength, good chemical stability, high fracture toughness, high hardness, low friction coefficient and good wear resistance.
In my doctoral thesis, that was conducted within the framework of a bilateral project between the Slovak Academy of Sciences (SAS) and Marmara Research Center (MRC) of the Scientific and Technological Research Council of Turkey (TUBITAK), the aim was to develop a composite ceramic biomaterial similar to human bone with defined porosity. Porous Si3N4 ceramics having “bone-like” micro and macro pores were produced using tape casting method by the project team at the Materials Institute of TUBITAK MRC.
A number of prescriptions were tried to produce the bone-like functionally graded porous Si3N4 ceramics by using different alcohols and adding various dispersing agents, binders, plasticizers and pore-forming agents. Tapes produced by tape casting method were laminated and pressed according to their properties and sintered at different temperatures after the removal of binder. Porous Si3N4 material was then coated with hydroxyapatite and its interaction was investigated. Microstructural examination, 3D tomography, mechanical and biological tests were carried on the final samples and the results were evaluated. Eventually a bioceramic material, with bone-like microstructure, based on silicon nitride, containing micro-and micro pores with gradual transition was developed. The studies are still in progress and the product is expected to respond to the special needs of patients in need of orthopedics and spine surgery.
Green samples (with varying porosity) produced by tape casting
Dr. Yasemin Tabak
TUBITAK Marmara Research Center