Cooling Conditions Influence on Cortical Bovine Bones Derived Hydroxyapatite

Abstract

The aim of the study is to highlight the influence of the cooling conditions on cortical bovine bones derived hydroxyapatite. Bone samples with thicknes of 50 mm were cut from the central part of the bovine femur with a jigsaw. Then, they were processed in order to remove all the proteins and collagen traces by boiling for 4 hours and heating and holding them at 450°C for 2 hours. They were heat treated at temperatures ranging from 1000° to 1300°C, being held for 3 hours and then rapidly cooled in air atmosphere or ice-water. A natural fracture of the samples appeared after the applied heat treatments, which allowed us to analyse the fragments without a further preparation. The morphological changes that occurred during the sample processing were highlighted using the scanning electron microscopy (SEM) techniques. The morphological changes occurred not only between the heat treated samples at different temperature, but also in samples cooled in different environments. Also, it was noticed that crystals sizes proportionaly increased with temperature, while the porosity considerably decreased and also a condensation of the porous matrix/structure appeared.