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A new study about corrosion behavior of CoCrMo alloy used as implant material exposed to the physiological serum and Hank's solution in different temperatures, electrolyte compositions and immersion time were simulated, using open circuit potential (OCP), potentiodynamic polarization curves (PPC) and electrochemical impedance spectroscopy (EIS.) From the results, it can be concluded that CoCrMo biomaterial is influenced by electrolyte composition and temperature, and the passive films were more protective when formed in presence of physiological serum. Comparing the Ecorr for both solutions, it is possible to verify that the Hank's solution presented values more negative for the two studied temperatures (25 and 37 °C), indicating a greater susceptibility to the corrosion process. Regarding the results of potentiodynamic polarization, the ipass, decreased as function of time, indicating a more protective passive film at 25 °C. In regards to the physiological serum, the highest ipass values at 37 ºC evidenced the formation of a less stable passive film. The different behavior of ipass in Hank's solution may be related to the competitiveness between a possible film of D-glucose and oxides of the alloy metals. EIS studies suggest that the film formed in presence of physiological serum is nobler than that with Hank's solution.

It was recently shown that the crystallinity of extracted bone mineral samples from the fin bones of zebrafish could increase over storage time. This would have implications in many studies in which the samples need to be stored until analysis. The aim of this study was to further evaluate if the crystallinity of extracted bone mineral increases over storage time. The extracted mineral was a biological bone-like apatite produced in osteoblast cell cultures. The overall characterization of the mineral was done by energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and high-resolution transmission electron microscopy. In order to evaluate possible changes in crystallinity over storage time, the same sample was analyzed by X-ray diffraction immediately after mineral extraction and after 18 months of storage. In conclusion, no statistically relevant changes were observed over storage time, although the occurrence of a slight increase in crystallinity could be discussed in the stored mineral sample.

In this work, the synthetic hydroxyapatite (HAP) was studied using different preparation routes to decrease the crystal size and to study the temperature effect on the HAP nano-sized hydroxyapatite crystallization. X-ray diffraction (XRD) analysis indicated that all samples were composed by crystalline and amorphous phases . The sample with greater quantity of amorphous phase (40% of total mass) was studied. The nano-sized hydroxyapatite powder was heated and studied at 300, 500, 700, 900 and 1150 °C. All samples were characterized by XRD and their XRD patterns refined using the Rietveld method. The crystallites presented an anisotropic form, being larger in the (001) direction. It was observed that the crystallite size increased continuously with the heating temperature and the eccentricity of the ellipsoidal shape changed from 2.75 at 300 °C to 1.94, 1.43, 1.04 and 1.00 respectively at 500, 700, 900 and 1150 °C. In order to better characterize the morphology of the HAP the samples were also examined using atomic force microscopy (AFM), infrared spectrometry (IR) and thermogravimetric analysis (TGA).