Biocompatibility of dense hydroxyapatite prepared using an SPS process

Abstract

In the present study, the preparation of dense hydroxyapatite (HAp) materials at relative low temperatures using a spark plasma sintering was carried out. The bioactivity of HAp samples prepared by a spark plasma sintering method was investigated by in vitro tests and compared with HAp obtained by a conventional hot-pressing method. No growth of bone-like HAp crystals on surface of HAp sintered by a conventional hot-pressing method at 1200 degrees C was observed after immersion in a simulated body fluid (SBF) for 2 days. However, many large bone-like HAp crystals were observed on the surface of HAp samples prepared by a spark plasma sintering at 1200 degrees C after 2 days in the SBF immersion test. Especially, the negatively charged surface of the HAp samples prepared by spark plasma sintering was covered with larger HAp crystals compared with the positively charged surface. The electric poling of HAp was measured using a thermally simulated current technique. This rapid growth of bone-like HAp crystals of the HAp samples made by spark plasma sintering was believed to be related with the OH(-) and/or Ca(2(+) ) ion deficiency at the grain boundaries of the HAp matrix grains as well as a small electric poling effect resulting during the spark plasma sintering process.

Zeolite / Apatite Composites: A Long-Term Assurance Material for the Disposal of Radioactive Waste

“…Regarding the perpendicular section, the orientation indexes of 100, 200, 210, 300 and 310 diffractions, corresponding to the a-and b-planes, were much higher than those of other planes. The orientation indexes are much higher than those reported in previous papers 34,35,41 . HAp sintered body with the oriented a,b-axis was fabricated by applying a slip cast in a high magnetic field 34,35 , and that with the oriented c-axis was by sintering HAp aggregates which hydrated from dicalcium phosphate dehydrate (DCPD) using an uniaxial press method 41 .…”

“…Thus, the fabrication of the sintered body has been widely investigated by many researchers [33][34][35][36][37][38][39][40][41] . The dense sintered HAp was fabricated by a conventional method 36,37 and a post sintering method 38 .…”

“…Pulse electric current sintering (PECS) has been applied to the fabrication of sintered bodies, such as SiC, Al 2 O 3 and Si 3 N 4 [42][43][44] . The sintered HAp was also fabricated by the PECS method at different temperatures from 700 °C to 1200 °C [33][34][35] . The specific feature of the PECS method was to fabricate sintered bodies with a relative density of 100 % at lower temperature and for shorter duration due to the rapid heating rate.…”

Transparent .BETA.-Tricalcium Phosphate Ceramics Prepared by Spark Plasma Sintering

“…1)6) The spark plasma sintering (SPS) method is quite effective for producing dense ceramics of calcium phosphates. 7), 8) In the present study, b TCP ceramics were prepared by SPS at temperatures ranging from 800 to 1000 C at a uniaxial pressure of 60 MPa for 10 min with a heating rate of 25 C/min.…”

Geomaterials: their application to environmental remediation

“…A three-component sintered body consisting of I 2 -zeolite A, an HA nanolayer, and hydroxyfluorapatite (HFA) was fabricated at 950 • C by pulsed electric current sintering (PECS) method [136][137][138]; it had a relative density of up to 98.1±2.2%, which was calculated by considering the HFA/zeolite weight ratio. The sintered body was brown owing to the retained iodine ( figure 14(I)).…”