Curing Behavior and Structure of Magnesium Phosphate Chemically Bonded Ceramics with Different MgO to KH2PO4 Ratios

Magnesium phosphate chemically bonded ceramics attracted much attention because of its good biocompatibility. In this work, curing behavior and microstructure of magnesium phosphate chemically bonded ceramics with different MgO to KH2PO4 ratios were investigated. The results showed that the setting time decreased and the maximum temperature during the solidifying process increased as the increase of MgO to KH2PO4 ratio. Phase compositions were different for those samples fabricated with different MgO to KH2PO4 ratios. KH2PO4, MgO, and hydrated product existed in the sample with lower MgO to KH2PO4 ratio because of the incomplete reaction, and numerous acicular polycrystals were found. There were only MgO and hydrated product existed with the higher MgO to KH2PO4 ratio. Besides, a gelatinous structure with lots of cracks was also found. Clearly, the properties of magnesium potassium phosphate chemically bonded ceramics could be controlled by changing the MgO to KH2PO4 ratio. It is better to fabricate magnesium phosphate chemically bonded ceramics with optimal structure and properties suitable for biomedical applications in range of MgO to KH2PO4 ratio from 3:1 to 4:1 in this preparating conditions.