Understanding the flash sintering behavior for hydroxyapatite

A study on flash sintering of hydroxyapatite (HA) is presented in this work. Electric fields up to 2000 V cm(-1) were tested, resulting in sintering at furnace temperature as low as 850 degrees C and density in excess to 90%. XRD and FTIR analysis show no decomposition of HA into other phases for conventional as well as for flash sintering. In general, the power (in log scale) versus temperature curve for HA is found to be different from that of other oxide materials and this is attributed to the microstructural changes taking place due to the dehydroxylation reaction occurring during flash sintering. In addition, high furnace temperature and high max power density during flash sintering seems to lead to the partial melting of the samples, giving (002) preferably oriented microstructure.