Porosity determinations in thermally sprayed hydroxyapatite coatings

The porosity of various thermally sprayed coatings was determined using an Archimedian Method. The method relies on density determinations and buoyanc y effects. First, measurements were carried out on standard samples in orde r to verify the accuracy and reliability of the Archimedian method. Then, p orosity measurements were taken for hydroxyapatite samples and correlated t o its physical properties. The results from the experiments show that as th e crystallinity of the HAp increases, the porosity increases. Also, as the amorphous content increases, porosity decreases. Other relationships indica ted that the porosity decreased as the stand off distance increased and it decreased with a power increase. (C) 2001 Kluwer Academic Publishers.