Use of cycles of compression to characterize the behaviour of apatitic phosphate powders

A method has been developed to analyse the bulk and mechanical properties of powders under pressure using a uniaxial press. This easy-to-use and rapid method requires small amounts of material and allows different compression parameters to be assessed. Classical parameters, e.g. compaction ratio and tensile strength, are determined. The recording of the compression and rupture cycles allows the energies of compression and of rupture to be calculated. The flowability of the powder is determined during the compression experiment. The energy of compression is linked with the elastic energy to help to explain the energy consumption during compression. It is also correlated to the rupture energy to evaluate the ability of the material to convert the energy of compaction into cohesion. This simple method has been applied to apatitic calcium phosphate powders differing in Ca/P molar ratio and/or crystallinity. It allowed to study the relation between chemical nature and compressibility.