Papers by Author: Niyazi Eruslu

Abstract: Composites of calcinated bovine bone derived hydroxyapatite (HA) with 5 and 10 wt % SrCO3 were prepared by sintering. The production of HA from natural sources is preferred due to money and time saving reasons. In this study scanning electron microscopy (SEM) investigations and together with measurements of microhardness, density, and compression strength were performed. The experimental results indicated that compression strength and microhardness values of HA-Sr-oxide composites decrease when the content of SrCO3 and sintering temperature increase. The best compression strength values were achieved after sintering at 1000°C. It was seen that at higher temperatures the compression strength and the microhardness values decrease due to the pore formation. The pore formation is very important for scaffold formation for tissue engineering purposes.

Abstract: Composites of calcinated bovine bone derived hydroxyapatite (HA) with 5, 7.5 and 10 wt % B2O3 were prepared by sintering. The production of HA from natural sources is preferred due to economical and time saving reasons. In this study scanning electron microscopy (SEM) investigations, microhardness and compression strength measurements were performed on composites. The experimental results indicated that compression strength and microhardness of HA-boron-oxide composites decrease when the content of boric acid and sintering temperature increase. The best mechanical properties achieved for 5 wt % addition of dehydrated boric acid. It was seen that at higher sintering temperatures, the compression strength and the microhardness decrease due to the very intensive pore formation. The results agree fairly well with microstructure analysis.

Abstract: Composites of calcinated bovine bone derived hydroxyapatite (BHA) doped 0.5 and 1 wt% CaF2 were prepared by sintering. The production of BHA from natural sources is preferred due to money and time saving reasons. Scanning electron microscopy (SEM) and X-ray diffraction analysis together with measurements of density and compression strength were carried out in the produced samples. The experimental results indicated that compression strength of the composites increase when sintering temperature increases. The best compression strength was achieved after sintering at 1200°C for 0.5% CaF2 addition. The results are in agreement with densification measurements and microstructure analysis. With regards to the amount of CaF2, the results indicate that small additions of F, lower than 0.5%, can further improve the mechanical properties of HA.

Abstract: Composites of bovine bone derived HA with 5 wt% and 10 wt% of TiO2 were sintered at different temperatures. Their characterization comprised measurements of density, microhardness, and compression strength together with SEM observations and X-ray diffraction analysis. Better densification behaviour was achieved at higher sintering temperatures. The highest microhardness value was measured in the samples sintered at 1300°C. The best compressive strengths of the samples containing 5% and 10% TiO2 were obtained after sintering at 1300°C and 1200°C, respectively.

Abstract: The purpose of this study is to investigate the crystallization behavior and in-vitro bioactivity character of glass ceramics having 3:7 weight ratio of flourapatite (Ca5(PO4)3F) to potassium mica (K2Mg3AlSi3O10F2) as a function of titania addition, and compare the morphology of hydroxycarbonateapatite (HCA) layer formation depending on titania addition on ceramic composition. It is observed from microstructural investigations that there is no morphology change occurred on precipitated HCA layer depending on nucleating agent in glass-ceramics. TF-XRD analysis indicates that after precipitation of initial particulates, crystallization proceeds and crystallization of precipitated HCA phase increases by increasing the time. It is observed that Ca, P ion variation in solution has two stage in terms of precipitation’ first stage represents formation of amorphous HCA and the second stage is related with crystallization. FTIR analysis strongly supports TF-XRD analysis as well.