Influencia de la temperatura en la compactación hidrotérmica en caliente de polvos de magnesio hidroxiapatita Influence of temperature on hydrothermal hot-pressing of magnesium hydroxyapatite powder

摘要

Preparation of hydrothermal hot-pressed (HHP) compacts of the stoichiometric hydroxyapatite and solid-solution of magnesium hydroxyapatite powders (HAp and Mg-HAp) was carry out at different temperatures 150, 175 and 200 °C, using uniaxial pressure load of 60 MPa for 6 h, with the addition of 10% wt. of deionized water as a solvent. The starting powders were obtained by hydrothermal synthesis at 150 °C for 10 h. The HHP compacts were chemical, physical and mechanically characterized. According to the results, it has been determined that an increase of the HHP temperature stimulate the reaction between the added water and the particles of HAp or Mg-HAp, which results on an increase of crystallinity degree without the formation of any addition products or alteration of the HAp structure. This result is particularly relevant, due to during HHP process, the production of effective packing of the particles which is activate by the dissolution-recrystallization mechanism in presence of added water which allow a densification near of 70%. For the HHP compacts of the HAp and Mg-HAp prepared at 200 °C, with porosity near to 30-36% of open pores, achieve the maximum apparent density value of 3.085 ± 0.138 g/cm3 and 2.792 ± 0.021 g/cm3, respectively, with the maximum tensile strength of 7.10 ± 0.20 and 5.89 ± 0.06 MPa. From these results, the obtained HHP compacts might be useful for orthopedics and/or dentist applications.