Preparation of Nano-sized Hydroxyapatite
Date Issued
2007
Date
2007
Author(s)
Chiu, Chin-Yi
DOI
en-US
Abstract
Stoichiometric hydroxyapatite precipitates with the size of 10~20 nm in diameter and 50~100nm in length were prepared by using a wet method (chemical co-precipitation) from the precursors of phosphate acid and calcium hydroxide. The nano powder was then used to prepare dense HAp body by using pressureless sintering. The present study strived to solve the problem of agglomeration of the nanocrystalline particles. A dispersant was added into the suspension before precipitates formed. The removal of dissolved gas from the slurry is also critical for the preparation of green compact. The nearly agglomeration-free particles were consolidated by centrifugation. If the agglomerates remain in the powder, higher sintering temperature is needed to eliminate inter-agglomerate pores. For the compact formed by the nearly agglomerate-free powder, nearly fully dense hydroxyapatite body could be produced by 1st step sintering at 1200°C and then 2nd step sintering at 1100°C for 20 hrs. The grain size below 400nm is obtained. High resolution X-ray diffraction analysis demonstrates that no decomposition takes place during the sintering at 1200°C.
Subjects
氫氧基磷灰石
膠粒製程
兩段燒結
奈米粉末
hydroxyapatite
colloidal process
two-step sintering
nano-sized particle
Type
thesis
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